Abstracts of the 1st International Online Conference on Gels ^†

1. Session 1: The Supramolecular Structure and Properties of Gels

1.1. Ascorbyl Palmitate Coagels (Coa-ASC16 _PEG): Easy-to-Prepare Delivery Systems with Optimal Rheology for Controlled Release

• Franco Maslovski ¹, Sofía Brignone ², Bruno Barrientos ^3,4, Santiago Palma ^3,4, Belkys Maletto ^5,6, Laura Leiva ^1,7 and Luciano Fusco ^1,7

¹ 

Instituto de Química Básica y Aplicada del Nordeste Argentino (IQUIBA-NEA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Corrientes W3400, Argentina

² 

Department of Pharmacy, University of Pisa, Via Bonanno 6, Pisa 56126, Italy

³ 

Departamento de Ciencias Farmacéuticas, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba X5000, Argentina

⁴ 

Unidad de Investigación y Desarrollo en Tecnología Farmacéutica (UNITEFA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba X5000, Argentina

⁵ 

Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba X5000, Argentina

⁶ 

Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba X5000, Argentina

⁷ 

Facultad de Ciencias Exactas y Naturales y Agrimensura, Universidad Nacional del Nordeste, Corrientes W3400, Argentina

Introduction: Hydrogels have received increasing attention as versatile platforms for bioactive compounds delivery, due to their viscoelasticity, injectability, and to provide sustained release. Among them, systems based on ascorbyl palmitate (ASC16) have exhibited shear-thinning behavior, biocompatibility, and the ability to form stable coagels, although their preparation requires relatively high formulation temperatures. It is known that the incorporation of polyethylene glycol 400 (PEG₄₀₀) significantly lowers the critical micelle temperature, enhancing their potential for biomedical applications.

Objective: This study aimed to develop and characterise an ASC16 coagel (Coa-ASC16) in PEG₄₀₀ (Coa-ASC16_PEG) through a novel formulation procedure, distinct from previously reported methods, as a low-cost and easy-to-prepare matrix for the encapsulation and controlled release of biomolecules, using ophidian venom proteins (OVPs) as a model.

Methods: Coa-ASC16_PEG was prepared at 2.5% (w/v) using a mixture of PEG₄₀₀ and water in a 4:1 ratio. ASC16 was dissolved in PEG₄₀₀ in glass tubes and heated to 64 °C until complete solubilization was achieved (≤2 min). The mixture was then cooled to 40 °C and allowed to reach thermal equilibrium, after which OVPs dissolved in water were added and mixed for 10 s (Coa-ASC16_PEG/OVP). The formulation was characterized using dynamic rotational rheology tests, a three-interval thixotropy test (3ITT), encapsulation efficiency measurements, and in vitro release assays.

Results: Coa-ASC16_PEG/OVP demonstrated high encapsulation efficiency (96.42 ± 1.06%), retained stability under protein overload, and enabled a sustained release of OVP over time (23.41 ± 6.12% at 360 min). Rheological analyses confirmed its viscoelastic behavior, while 3ITT revealed a robust capacity to recover the original viscosity following mechanical stress.

Conclusions: Coa-ASC16_PEG represents a simple, low-cost platform with favorable rheological properties and high protein loading capacity. Its ability to withstand mechanical stress while providing sustained release highlights its potential as a controlled-release system for biomolecules, with potential applications in biomedical research.

1.2. Gelation of Solvents with Amphiphilic Amino-Acid Derivatives: Use of Molecular Spectroscopy to Elucidate Self-Assembly Process

• Geraldine Rangel ¹, Marie-Christine Averlant-Petit ², Loïc Stefan ², Alain Durand ² and Guillaume Pickaert ²

¹ 

UR1268 BIA, INRAE, 44300 Nantes, France

² 

LCPM, Université de Lorraine, CNRS, F-54000 Nancy, France

Molecular gels are materials that have been growing in popularity over the last twenty years. In addition to their potential applications in cosmetics, pharmacology, cell culture, and catalysis [1], their intrinsic physicochemical properties make them fascinating objects of study. The gelators used are low-molecular-weight molecules (less than 2000 gmol⁻¹) capable of self-assembling via weak interactions to generate a fiber-like three-dimensional solid network, in which solvent molecules are trapped [1,2]. Changes to the chemical structure of gelators, as well as the nature of the solvent to be immobilized, can induce spectacular changes in the mechanical properties of the final gel. Thus, they are crucial parameters to consider during the various stages of the sequential self-assembly process, particularly during the first one: nucleation. These molecular gels can be viewed as crystallizations that have gone wrong. Instead of having well-defined crystals, crystallization occurs randomly throughout the volume of solvent. This raises the following question: What is the real impact of the chemical structure of gelling agents, and the resulting intermolecular interactions, on the macroscopic properties of the materials obtained?

In our group, we work on amphiphilic amino acid (leucine, phenylalanine, and lysine [3])-based gelators. Those molecules bear an alkyl chain of different length at the N-terminal extremity and a carboxylic acid or derivatives (ester, hydrazide…) at the C-terminal extremity. With these gelators, we can immobilise, among a wide range of various fluids, alkanes, DMSO/water mixtures, or oils. Using molecular analysis techniques, such as FT-IR and NMR, we examine the behaviour of gelling agents at the molecular level in different solvents.

• References

• Raeburn, J.; Adams, D. Multicomponent low molecular weight gelators. Chem. Communication. 2015, 51, 5170–5180. https://doi.org/10.1039/C4CC08626K.
• Collin, D.; Covis RAllix, F.; Jamart-Gregroire, B.; Martinoty, P. Jamming transition in solutions containing organogelator molecules of amino-acid type: rheological and calorimetry experiments†. Soft Matter. 2013, 9, 2947–2958. https://doi.org/10.1039/C2SM26091C.
• Rangel Euzcateguy, G.; Parajua-Sejil, C.; Marchal, P.; Chapron, D.; Averlant-Petit, M.-C.; Stefan, L.; Pickaert, G.; Durand, A. Rheological investigation of supramolecular physical gels in water/dimethylsulfoxide mixtures by lysine derivatives. Polym. Int. 2021, 70, 256–268. https://doi.org/10.1002/pi.6179.

1.3. Low-Molecular-Weight Peptide-Based Formulations: From Hydrogels to Nanogels

• Carlo Diaferia ¹, Elisabetta Rosa ², Mariangela Rosa ², Giancarlo Morelli ² and Antonella Accardo ²

¹ 

Department of Pharmacy, University of Naples “Federico II” and CIRPeB (Centro Interuniversitario di Ricerca sui Peptide Bioattivi “Carlo Pedone”), 80145 Naples, Italy

² 

Department of Pharmacy, University of Naples «Federico II», Via D. Montesano 49, 80131 Naples, Italy

Peptide-based supramolecular low-molecular-weight gelators have emerged as promising materials across various fields, including healthcare, cosmetics, and bioanalysis. Their advance highlights the increasing importance of gels as foundational elements and tools in next-generation technologies. Advances in the structural, functional, and production-related aspects of peptide-based gels—combined with their biocompatibility, responsiveness to chemical modifications, and suitability for rational de novo design—are accelerating their adoption in pharmaceutical science, too. Among recent innovations, peptide-based nanogels have gained particular interest. These injectable, nanoscale objects are closely related to hydrogel organization in their core and are stabilized by a surfactant shell. Formulated using self-assembling ultrashort peptides (e.g., Fmoc-FF), they are produced through a refined top-down approach that enables precise control over particle characteristics. This optimized methodology has positioned peptide nanogels as versatile platforms for expanding the scope of gel-based applications. These formulations have demonstrated an ability to encapsulate a wide range of active pharmaceutical ingredients (APIs), such as doxorubicin, dexamethasone, short interfering RNA (siRNA), gadolinium-based contrast agents, and chemical exchange saturation transfer (CEST) agents. Their colloidal stability, capacity for drug inclusion, controlled release profiles, and selective targeting potential underline their functionality in therapeutic and diagnostic contexts. Overall, peptide-based nanogels represent a significant advance in the formulation of responsive, biocompatible delivery systems, offering new possibilities in targeted drug delivery and biomedical imaging.

1.4. Minimalistic Tryptophan-Based Supramolecular Hydrogel as a Versatile Catalytic Scaffold

• Ipsita Sahu and Priyadarshi Chakraborty
• Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, Sangareddy 502284, Telangana, India

Single amino acids and their derivatives possess a remarkable propensity to self-assemble into ordered nanostructures that can exhibit catalytic functions [1,2]. Although there are numerous instances of catalysis using peptide nanostructures inspired by amyloid fibres [3,4], hydrogel-based catalysts produced from a single amino acid are few. In this study, we demonstrate the self-assembly of N-fluorenylmethyloxycarbonyl-L-tryptophan (FT) into a nanofibrous hydrogel capable of catalyzing the hydrolysis of p-nitrophenyl acetate. The FT hydrogel exhibits pathway complexity, progressing from kinetically trapped nanofibers to thermodynamically stable semicrystalline aggregates with improved catalytic efficiency, as evidenced by comparative studies with the monomers and the gel fibers⁵. Functional attributes were further improved by nanoengineering the FT network with graphene oxide and graphene quantum dots, yielding composites with enhanced mechanical strength and enzyme-like hydrolase activity, supported by Michaelis–Menten kinetic analysis. Furthermore, in situ reduction of Au³⁺ within the FT gel scaffold produced AuNPs without external reducing agents, leveraging the reductive capability of the indole moiety. This FT/AuNP nanohybrid gel enables rapid reductive degradation of both cationic and anionic dyes in aqueous media. For enhanced handling and practical applications, we fabricated alginate-supported FT/AuNPs core-shell hydrogel beads, which retained structural integrity and high catalytic efficiency, achieving more than 90% dye removal with a single 20 µL bead [5]. Altogether, this showcases the potential of single amino acid-derived self-assembled hydrogels/semicrystalline aggregates and their nanohybrids as effective, tunable, and sustainable catalytic systems for both synthetic and environmental applications.

• References

• Makam, P.; Yamijala, S.S.; Bhadram, V.S.; Shimon, L.J.; Wong, B.M.; Gazit, E. Single amino acid bionanozyme for environmental remediation. Nat. Commun. 2022, 13, 1505. https://doi.org/10.1038/s41467-022-28942-0.
• Makhlynets, O.V.; Korendovych, I.V. A single amino acid enzyme. Nat. Catal. 2019, 2, 949–950. https://doi.org/10.1038/s41929-019-0379-3.
• Chatterjee, A.; Reja, A.; Pal, P.; Das, D. Systems chemistry of peptide-assemblies for biochemical transformations. Chem. Soc. Rev. 2022, 51, 3047–3070. https://doi.org/10.1039/D1CS01178B.
• Smith, K. Supramolecular Gels as Active Tools for Reaction Engineering. Angew. Chem. 2025, 64, e202502053. https://doi.org/10.1002/anie.202502053.
• Sahu, D.; Saha, S.; Pande, D, Verma, J.; Chakraborty, P. Single Amino Acid Derived Rudimentary Catalytic Hydrogel for Reaction Engineering. ACS Appl. Mater. Interfaces 2025, 17, 48240–48256. https://doi.org/10.1021/acsami.5c09633.

1.5. Supramolecular Gels and Their Modification for Electrochemical Application

• Debolina Saha and Priyadarshi Chakrobarty
• Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, Sangareddy 502285, Telangana, India

Supramolecular gels with tailored optoelectronic behavior are of increasing interest for applications in soft electronics, sensing, and energy-related devices. In this study, we examined the donor–acceptor interactions of three aromatic amine donors, 2-aminoanthracene, 1-aminopyrene, and 2-aminonaphthalene, with diphenylalanine as the acceptor in both solution and gel phases. In solution, molar ratio studies revealed that the 2-aminoanthracene–diphenylalanine system displayed the strongest charge-transfer interaction, evident from a pronounced color change within 24 h. The pyrene and naphthalene systems showed weaker responses under identical conditions. By increasing the gelator concentration, stable supramolecular gels were obtained, where similar charge-transfer trends were observed. Anthracene–diphenylalanine gels exhibited the fastest and most prominent optical and spectroscopic changes, followed by pyrene and then naphthalene. The mechanical strength of the gels was evaluated, and structural characterization by PXRD, FTIR, TEM, and fluorescence microscopy confirmed the presence of crystalline fibrous networks across all systems. Conductivity and photocurrent measurements further demonstrated that anthracene–diphenylalanine gels possessed superior electronic performance compared to the other donor–acceptor assemblies. To further enhance the functional properties, nanomaterials such as graphene oxide (GO), graphene quantum dots (GQDs), and carbon nanotubes (CNTs) were incorporated into the gels. Notably, CNT-doped gels exhibited the most significant improvements, showing enhanced conductivity and electron storage capacity. This enhancement is attributed to improved charge delocalization and the creation of efficient transport pathways within the fibrous matrix.

In summary, this work establishes diphenylalanine based donor–acceptor gels, particularly those incorporating 2-aminoanthracene, as versatile materials with promising optoelectronic features. The incorporation of CNT provides a simple yet effective strategy to boost conductivity and energy storage performance, opening new opportunities for developing soft, hybrid materials for advanced electronic and energy applications.

1.6. Supramolecularly Reinforced Hydrogel Scaffolds for Advanced Tissue Engineering

• Shreya Pande ¹, Priyadarshi Chakraborty ² and Falguni Pati ¹

¹ 

Department of Biomedical Engineering, Indian Institute of Technology Hyderabad, Sangareddy 502285, Telangana, India

² 

Department of Chemistry, Indian Institute of Technology Hyderabad, Sangareeddy 502285, Telangana, India

The regeneration of articular cartilage is hindered by the absence of intrinsic repair mechanisms and the lack of scaffolds that integrate both biochemical functionality and mechanical resilience. Conventional hydrogels capture certain aspects of the native niche yet remain limited by weak supramolecular cohesion and insufficient load-bearing capacity. To overcome these barriers, a hybrid hydrogel was engineered by coupling decellularized cartilage extracellular matrix (dECM) with the self-assembling peptide: fluorenylmethoxycarbonyl-modified amino acids (Fmoc-xx). Hydrogels derived from dECM retain native proteins and signaling motifs but typically collapse under physiological stresses, restricting their therapeutic value. While dECM offers native adhesion sites and instructive biochemical cues, Fmoc-xx nanofibers form a supramolecular framework that interpenetrates ECM macromolecules through hydrogen bonding and aromatic π–π stacking. These cooperative interactions generate a hierarchically organized network that transforms the mechanically fragile dECM hydrogel into a resilient, load-bearing construct. This molecular reinforcement elevated the storage modulus by nearly three orders (~1000 fold increase) of magnitude while preserving hydration and network stability. Furthermore, the hybrid scaffold provided a cell-compatible niche that enabled rapid chondrocyte adhesion as well as sustained proliferation. The hybrid hydrogel could maintain the chondrogenic phenotype, underscoring the synergy between structural resilience and biological fidelity. By uniting supramolecular self-assembly with native matrix bioactivity, this work advances a materials strategy that converts fragile dECM gels into robust, functional scaffolds. Such reinforced hydrogels do not merely mimic tissue microenvironments but actively integrate strength with bioactivity, positioning them as next-generation platforms for cartilage regeneration and broader tissue engineering applications.

1.7. The Spectral Viscoelasticity of Gels, Fast and Slow

• Horst Henning Winter
• Department of Chemical Engineering and Department of Polymer Science and Engineering, University of Massachusetts Amherst, Amherst, MA 01003, USA

Gels uniquely combine elasticity and viscosity, making them effective for damping, impact absorption, and noise control. In adhesives, this duality provides both structural strength and vibration management. Viscoelastic behavior arises from two contributions: permanent elasticity, described by the equilibrium modulus G₀, and a spectrum of transient relaxation modes (eigenmodes) with relaxation times that range from milliseconds to the longest relaxation time τ_max extending hours or longer. The fast/slow interplay of eigenmodes governs applications of viscoelastic materials yet often remains obscured in classical rheology. We address this limitation with the SCOPE framework (Spectral Characterization of Process and Eigenmodes). To each eigenmode, SCOPE assigns a spectral Deborah function D and spectral Weissenberg function W, which provide natural, physically transparent criteria for gel classification.

The Deborah function (Winter, Rheologica Acta 2025) compares an eigenmode’s relaxation time with the characteristic timescales of a process. When D1, the eigenmode relaxes before the process is completed, giving rise to a predominantly viscous response. When D > 1, relaxation is incomplete, and the eigenmode contributes predominantly to elastic behavior.

The Weissenberg function, by contrast, spectroscopically measures the strain accumulated during a relaxation time τ. It quantifies how much deformation an eigenmode “remembers” before relaxing. For W > 1, deformation grows more rapidly than relaxation can erase memory, separating eigenmodes that generate secondary flow effects (e.g., rod climbing in shear, strain hardening in extension) from those that do not. In addition, W provides a spectroscopic criterion for the onset of nonlinearity: when W exceeds a critical strain γ_c, the specific eigenmode leaves the linear regime. The condition W/γ_c = 1 therefore marks the threshold between linear and nonlinear eigenmodes.

Interactions of G₀, D, and W within SCOPE offer complementary spectroscopic perspectives on gel behavior. This will be demonstrated using IRIS Rheo-Hub, a machine learning tool for rheology data analysis, modeling, and visualization.

2. Session 2: Hydrogels, Organogels, Xerogels, and Aerogels

2.1. Development of a Janus Nanocomposite Hydrogel Based on Lignin and Polyelectrolyte sIPN for Enhanced Wastewater Treatment via Interfacial Solar Steam Generation

• Aboulfazl Barati
• Center for Materials and Manufacturing Sciences, Department of Chemistry and Physics, Troy University, Troy, AL, USA

Introduction:

• This study aims to develop a multifunctional Janus hydrogel composed of lignin, fumed silica nanoparticles, and a polyelectrolyte semi-interpenetrating network (sIPN) for interfacial solar steam generation (ISSG) and ion exchange-based wastewater treatment. Addressing salt fouling and low contaminant removal efficiency in current ISSG systems, the proposed Janus hydrogel integrates both hydrophilic and hydrophobic domains to optimize water transport, evaporation, and contaminant rejection.

Methods:

• The Janus hydrogel was synthesized by integrating lignin as a bio-based functional filler and fumed silica as a nanostructured backbone into an sIPN composed of partially neutralized acrylic acid. The hydrophilic layer was designed using covalently crosslinked polyelectrolytes rich in carboxyl and hydroxyl groups, while the opposing hydrophobic layer was fabricated by surface-modifying fumed silica using long-chain alkyl silanes. The Janus interface was formed via controlled casting to ensure a stable interface between the two layers. Characterization techniques included FTIR, SEM, AFM, the swelling ratio, ion exchange capacity, and water evaporation efficiency under simulated solar irradiation.

Results:

• The hydrogel demonstrated a swelling capacity exceeding 1000%, an ion exchange capacity of 3.1 mmol/g, and over 90% heavy metal ion removal efficiency. The Janus structure enabled directional water transport and minimized salt accumulation at the surface. Solar steam generation efficiency reached 87% under 1 sun, with stable performance in saline and heavy metal-contaminated wastewater.

Conclusions:

• This novel Janus nanocomposite hydrogel offers a promising platform for sustainable wastewater treatment by combining lignin’s functional versatility, silica’s structural reinforcement, and the sIPN’s tunable transport properties. The approach supports efficient and eco-friendly water purification using solar energy, aligned with global water sustainability goals.

2.2. Structural, Textural, and Rheological Attributes of Emulgels for Cocoa Butter Replacement

• Jiana Rebeca Matamoros, Lina Casale Aragon-Alegro and Roberta Claro da Silva
• Department of Family and Consumer Sciences, North Carolina Agricultural and Technical State University, Greensboro, NC 27411, USA

Cocoa butter is an essential component in chocolate production, contributing to its texture, crystallization, and sensory attributes. However, its fatty composition and high production costs, sustainability concerns, and health issues have led to the search for alternatives to partially replace this fat. Understanding the rheological and textural characteristics of cocoa butter is essential to ensure the stability of the final product. This research aimed to evaluate the structural, rheological, and textural attributes of emulgels for partial cocoa butter substitution in chocolate production. A total of nine distinct emulgels were created using coconut oil, high oleic sunflower oil, rice bran wax, and monoglycerides as the foundational components of the formulations. These were combined with hydrocolloids, including pectin (P), gelatin (G), or xanthan gum (X), at concentrations of 1%, 2%, and 3% in the aqueous phase, maintaining a ratio of 8:2 (v/v). Analyses such as rheology, texture, and visual were performed. The visual analysis revealed a homogeneous, solid-like material with no signs of phase separation in all samples. The microscopy analyses confirmed that the samples presented well-formed crystalline networks with small homogeneous crystals. Emulsions containing G exhibited higher viscoelasticity compared to those containing P and X. However, an important observation was that samples containing more than 2% hydrocolloid displayed black spots resembling holes in the micrographs. These structural discontinuities suggest the presence of voids or phase separation, which likely disrupted the integrity of the crystal–polymer network. Consistently, these samples showed a direct impact on their rheological parameters, indicating that excessive hydrocolloid concentrations negatively influenced the uniformity and stability of the matrix. The sample containing 2% rice bran wax, 5% monoglycerides, and 3% gelatin showed good oil entrapment and good rheological and texture characteristics and is an excellent candidate for partially replacing cocoa butter in chocolate manufacturing.

2.3. Cellulose-in-Cellulose 3D-Printed Hydrogels and Aerogels for Soft Tissue Engineering

• Ana Iglesias-Mejuto ^1,2,3, Sergi Díaz ¹, Carlos A. García González ², Catarina Pinto Reis ^3,4, Anna Roig ¹ and Anna Laromaine ¹

¹ 

Institute of Materials Science of Barcelona, ICMAB-CSIC, Campus UAB, 08193 Bellaterra, Spain

² 

Department of Pharmacology, Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, iMATUS and Health Research Institute of Santiago de Compostela (IDIS), University of Santiago de Compostela, E-15782 Santiago de Compostela, Spain

³ 

Research Institute for Medicines (iMed. ULisboa), Faculty of Pharmacy, University of Lisbon, Av. Professor Gama Pinto, 1649-003 Lisbon, Portugal

⁴ 

Institute of Biophysics and Biomedical Engineering (IBEB), Faculty of Sciences, University of Lisbon, Campo Grande, 1749-016 Lisbon, Portugal

Introduction

Bacterial cellulose is one of the cellulose derivatives with the greatest purity and porosity, so it has sparked interest in the regenerative medicine field [1]. Nevertheless, the addition of bacterial cellulose nanofibers modifies the rheological properties of 3D printing inks, so certain applications of nanocellulose as part of 3D-printed gels have barely been explored.

Methodology

In this work, bacterial cellulose nanofibers are obtained through a well-established protocol from the bacterial strain K. xylinus [1,2,3] and were added into methylcellulose inks to manufacture 3D-printed hydrogels and aerogels. Polyurea crosslinking was explored as a method to enhance the performance of the cellulose-in-cellulose gels. Scanning and transmission electron microscopies as well as printing fidelity measurements were employed to characterize the gels. Cell studies and hemolytic activity tests were conducted to ensure the absence of toxicity of the formulations.

Results and Discussion

Bacterial cellulose nanofibers were obtained with a diameter close to 50 nm and were incorporated into methylcellulose inks, with shear-thinning properties adequate for 3D printing. Nanocellulose added into gels decreased their volume shrinkage and increased their printing fidelity. Polyurea crosslinking yielded biocompatible gels with enhanced structural properties. The results obtained encourage future research on these gels as soft tissue grafts.

Conclusions

Bacterial cellulose nanofibers were incorporated into 3D-printed methylcellulose hydrogels and aerogels, yielding structures with morphological properties suitable for soft tissue engineering. The polyurea crosslinking of the cellulose-in-cellulose gels enhanced their physicochemical performance, resulting in promising formulations for regenerative medicine.

Acknowledgments

This work was funded by MICIU/AEI/10.13039/501100011033 [grants PID2023-151340OBI00, PDC2022-133526-I00, and PDC2023-145826-I00], Xunta de Galicia [ED431C2022/2023], ERDF/EU, and European Union NextGenerationEU/PRTR. A. I.-M. acknowledges Xunta de Galicia for her postdoctoral fellowship [ED481B-2025/032].

• References

• Malandain, N.; Sanz-Fraile, H.; Farré, R.; Otero, J.; Roig, A.; Laromaine, A. Cell-Laden 3D Hydrogels of Type I Collagen Incorporating Bacterial Nanocellulose Fibers. ACS Appl. Bio. Mater. 2023, 6, 3638–3647. https://doi.org/10.1021/acsabm.3c00126.
• Iglesias-Mejuto, A.; Malandain, N.; Ferreira-Gonçalves, T.; Ardao, I.; Reis, C.P.; Laromaine, A.; Roig, A.; García-González, C.A. Cellulose-in-cellulose 3D-printed bioaerogels for bone tissue engineering. Cellulose 2024, 31, 515–534. https://doi.org/10.1007/s10570-023-05601-1.
• Iglesias-Mejuto, A.; Raptopoulos, G.; Malandain, N.; Neves Amaral, M.; Ardao, I.; Finšgar, M.; Laromaine, A.; Roig, A.; Pinto Reis, C.; García-González, C.A.; et al. 3D-Printed Cellulose Aerogels Minimally Cross-Linked with Polyurea: A Robust Strategy for Tissue Engineering. ACS Appl. Mater. Interfaces 2025, 17, 34444–34457. https://doi.org/10.1021/acsami.5c08389.

2.4. Preparation of Elastic PVA/PAAm Double-Network Hydrogel for Application in Artificial Blood Vessel Materials

• Akemi Nagao ¹, Masatoshi Iriki-in ¹, Kenta Tanaka ¹, Masakazu Muto ² and Kazuya U. Kobayashi ¹

¹ 

Faculty of Fundamental Engineering, Nipppon Institute of Technology, Saitama Prifecture, 345-8501, 4-1 gakuendai miyashiro-cho saitama-gun, Japan

² 

Graduate School of Electrical and Mechanical Engineering, The Nagoya Institute of Technology, Aich Prifecture, 466-0061, gokiso-cho, atuta-shi, sowa-ku, Japan

It is well known that polyvinyl alcohol (PVA) forms hydrogels in aqueous solutions, and its application in the field of biomaterials has long been anticipated. Recently a PVA–polyacrylamide (PAAm) double-network (DN) hydrogel has been developed through a repeated freeze–thaw cycle method to achieve sufficient mechanical strength. However, the DN gels are sometimes not sufficiently transparent due to the preparation process and because of crystallization, and their fields of application are limited. In this study, we developed a simple preparation process of thick and transparent PVA/PAAm DN hydrogels. The DN gel was synthesized from crushed PVA gel (the first gel)and an AAm solution (the monomer of the second gel). In total, 1.32 g of PVA (saponification degree 98~99 mol%) was dissolved in DMSO–water (with a mass ratio of 2:8) and the total weight was adjusted to 30 g. The solution was then heated at 90 °C under stirring until the PVA was fully dissolved and cooled at −40 °C for 24 h.

The resulting PVA gel was finely ground with a mortar and pestle while mixing with 300 g of water solution containing 21.3 g of AAm, 0.04 g of the polymerization initiator 2-oxoglutaric acid (OA), and 0.04 g of the crosslinker N,N′ methylenebisacrylamide (MBAA). This mixture was poured into a cubic mold (25 mm per side) made of slide glass, and ultraviolet UV (365 nm) irradiation was applied to initiate the radical polymerization of the AAm. Through this process, a transparent and elastic PVA/PAAm DN hydrogel was obtained. Although the Young’s modulus of the DN gel (0.012 MPa) slightly failed to fall within this range for human blood vessels (0.02~3 MPa), its transparency may allow for the measurement of stress interactions between blood flow and vessel walls using photoelasticity. The thick and transparent DN gel made using PVA—produced at low cost—is also expected to be applied as a biomimetic material.

2.5. Biobased Derivatives from Olive Oil for Tuning Physically Crosslinked Poly(Vinyl alcohol) Hydrogel Properties

• Francisca Werlinger ¹, Valentino Cárdenas-Toledo ², Pablo Uribe ², Silvia Oyarzo-Aro ², Victor Mayorga ², Jose Luis Obando ³, Anibal Concha-Meyer ³, Alfredo Pereira ⁴, Javier Martinez ⁵, Oleksandra S. Trofymchuk ⁵ and Mario E. Flores ²

¹ 

Department of Organic Chemistry, Faculty of Chemical Sciences, University of Concepción, Concepción 4030000, Chile

² 

Institute of Chemical Sciences, Faculty of Sciences, Austral University of Chile, Valdivia 5090000, Chile

³ 

Institute of Food Science and Technology, Faculty of Agricultural and Food Sciences, Austral University of Chile, Valdivia 5090000, Chile

⁴ 

Faculty of Engineering, University of San Sebastián, Santiago 8320000, Chile

⁵ 

Department of Organic and Physical Chemistry, Faculty of Chemical and Pharmaceutical Sciences, University of Chile, Santiago 8380492, Chile

Vegetable oils, commonly discarded by kitchens and restaurants, comprise unsaturated triglycerides, and the double bonds present in triglyceride units can be readily converted into interesting precursors through various synthetic methods. In this contribution, we present a straightforward chemical methodology for the revalorization of cooking oil, towards using waste vegetable oil as a source to produce new building blocks for various applications. Specifically, the epoxidation of olive oil primarily yields an epoxidized oil derivative. This same epoxidation pathway can be applied to generate hydroxylated derivatives, such as diols.

These oil-based derivatives were then incorporated into the formulation of physically crosslinked PVA hydrogels. Notably, hydrogels containing a 5 wt% diol derivative exhibited the highest compressive Young’s modulus, suggesting a significant interaction between PVA and the diol.

Although no apparent changes were observed in the spectroscopic response of the PVA-based hydrogels, molecular dynamics simulations indicated a profound interaction between PVA and diol molecules. Additionally, all synthesized PVA-based hydrogels demonstrated a bacteriostatic effect against L. monocytogenes, compared to pristine PVA hydrogel. This suggests that PVA-based hydrogels containing olive oil derivatives could have promising applications in various fields, including the tailored control of diol structures to modulate not only the mechanical properties of the hydrogels but also their antibacterial properties.

2.6. Design and Development of an Injectable Hydrogel for Cartilage Repair

• Arjan Atwal ^1,2, Ali Mahnavi ^1,2, Martyn Snow ³, Nicholas R. Forsyth ⁴ and Pooya Davoodi ^1,2

¹ 

Guy Hilton Research Centre, Keele University, Staffordshire ST4 7QB, UK

² 

School of Allied Health Professions and Pharmacy, Keele University, Staffordshire ST5 5BG, UK

³ 

Department of Arthroscopy, Royal Orthopaedic Hospital NHS Foundation Trust, Birmingham B31 2AP, UK

⁴ 

Vice Principals’ Office, University of Aberdeen, Kings College, Aberdeen AB24 3FX, UK

Articular cartilage injuries present a significant clinical challenge due to the tissue’s limited intrinsic capacity for self-repair. Without effective treatment, such defects progress to osteoarthritis, severely impacting the patient’s mobility and quality of life. Existing clinical strategies, including microfracture and autologous chondrocyte implantation (ACI), are often associated with complications such as fibrocartilage formation and donor site morbidity. Injectable hydrogels offer a minimally invasive strategy with defect-conforming properties with the ability to deliver bioactive cues, yet conventional bulk ‘filler’ hydrogels are hindered by nanoporosity that limits nutrient transport and cell migration.

To overcome these limitations, a granular injectable hydrogel system was developed, composed of microparticles assembled from fragmented bulk hydrogels, thereby introducing interstitial microporosity to enhance cellular interactions and tissue integration. The hydrogel formulation was composed of gelatin methacryloyl-, hyaluronic acid methacryloyl-, and methacryloyl-modified platelet lysate. Bulk formulations were first optimized through live/dead viability assays, DNA and glycosaminoglycan quantification, and immunofluorescent staining for hyaline cartilage-specific markers. Granular hydrogels were fabricated by extruding and fragmenting the optimized bulk gels into microparticles, followed by centrifugation and photoannealing (λ = 365 nm). These constructs were evaluated using the same in vitro assays and further tested in an ex vivo osteochondral defect model.

Fabrication yielded large and small microparticles of 230 ± 82 µm and 46 ± 18 µm, respectively, with interstitial porosity ranging from 3–11% depending on centrifugation speed. While the optimized bulk hydrogel supported chondrocyte viability (+90%) and hyaline-like matrix production, granular hydrogels substantially improved repair outcomes. By day 31, GAG/DNA ratios reached 0.79 and 0.72 for small particle and large particle groups, compared to 0.677 for bulk gels. We report enhanced microporosity facilitated cell infiltration, more extracellular matrix deposition, and better integration with host cartilage. Immunostaining confirmed that the regenerated tissue was rich in type II collagen and aggrecan, resembling native hyaline cartilage.

2.7. Green and Sustainable Energy Storage Using Borax–Chitosan Hydrogel Electrolytes in EDLCs

• Dipankar Hazarika
• Department of Chemistry, Nagaland University, Lumami, Zunheboto, Nagaland, India

The growing concerns over chemical pollution and the rapid accumulation of microplastics necessitate the development of sustainable and high-performance energy storage systems. Among these, electrical double-layer capacitors (EDLCs) stand out for their remarkable cycling stability, yet their practical utility is often limited by their low energy density and their reliance on environmentally harmful liquid electrolytes. In this work, we present a facile, eco-friendly synthesis of a borax-crosslinked chitosan hydrogel membrane electrolyte (BCCHME). Borax simultaneously facilitates ionic and covalent crosslinking, thereby reinforcing the mechanical strength and enhancing ion mobility within the membrane. The optimized BCCHME demonstrates a 182% water uptake, 14.65% dissolution ratio, and a semi-crystalline framework with 16.59% crystallinity, supported by a uniform porous morphology. Structural verification through FTIR confirms the dual crosslinking, while elemental mapping reveals the presence of Na, B, C, N, and O. Electrochemical evaluation shows a high dielectric constant, an ionic conductivity of 7.03 × 10⁻⁴ S cm⁻¹, an ion transference number of 0.93, a diffusion coefficient of 4.19 × 10⁻⁹ m²s⁻¹, and electrochemical stability up to 2.24 V. A solid-state EDLC fabricated using BCCHME and Black Pearls’ carbon (BPC) electrodes achieves an areal capacitance of 378 mF cm⁻², an energy density of 52.5 µWh cm⁻², and a power density of 5000 µW cm⁻² at 5 mA cm⁻². The device also exhibits outstanding cycle life, maintaining performance for 53,000 cycles at 2 mA cm⁻² and 30,000 cycles at 5 mA cm⁻². Furthermore, a prototype configuration powered a 1 V LED for 1.83 min. Overall, this study demonstrates BCCHME as a biodegradable and non-toxic hydrogel electrolyte, merging sustainability with practical device-level performance for next-generation supercapacitors.

2.8. Hydrophobic Eutectics-Based Supramolecular Gels and Cellulose-Based Nanosponges: Breakthrough Solutions for Water Remediation

• Gloria Nicastro, Chiara Carotti, Arianna Rossetti, Alberto Mannu, Grazia Isa C. Righetti, Francesco Briatico-Vangosa, Andrea Mele, Carlo Punta, Laura Riva and Maria Enrica Di Pietro
• Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”, Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133 Milano, Italy

Clean water is a fundamental goal of the 2030 Agenda for Sustainable Development [1] and the European Green Deal’s Zero Pollution Action Plan [2], making water remediation a critical focus in research. Conventional extraction techniques like dispersive liquid–liquid and solid–liquid microextraction face challenges, including the use of volatile organic solvents and non-sustainable sorbents with limited capacity.

This study addresses these challenges by introducing new classes of sustainable materials based on hydrophobic non-ionic eutectic solvents (HESs) [3]. HESs offer several advantages, including being chloride-free and easy to prepare from natural precursors, 100% atom economy, and high sustainability [4]. To expand their use, two innovative HES-based materials are developed: hydrophobic eutectogels (HEGs) and HES-loaded cellulose nanosponges (HECSs).

HEGs are supramolecular gels formed by the rapid thermoreversible self-assembly of low molecular weight gelators [3]. HECSs are materials obtained by combination of HESs with peculiar aerogels composed of derivatized cellulose [5], a crosslinker (either a branched polyethyleneimine or gelatin) and a co-crosslinker [6,7].

The materials’ properties are being investigated both morphologically and mechanically by a multi-technique approach.

Preliminary studies with HEGs and HECSs have demonstrated promising extraction abilities in water remediation. In particular, HEGs and HECSs were used to extract bisphenol A from water, obtaining extraction efficiencies >90%, while menthol leaching rates appeared to be limited (0.35%).

This comprehensive materials study allows for precise control over their properties, making our systems highly adaptable for various applications.

The development of HEGs and HECSs marks a breakthrough in sustainable water treatment. By overcoming the limitations of current extraction methods, this research offers a safer, more efficient, and eco-friendly solution for removing harmful contaminants. The easy production, combined with easy recovery from the medium, pave the way to possible large-scale use. These materials have the potential to play a crucial role in achieving global clean water goals and advancing the field of green chemistry.

• References

• United Nations, “The 2030 Agenda for Sustainable Development,” Available online: https://sdgs.un.org/goals.
• European Commission, “Zero Pollution Action Plan,”. Available online: https://environment.ec.europa.eu/strategy/zero-pollution-action-plan_en.
• e Souza, G.D.A.L.; Di Pietro, M.E.; Vanoli, V.; Panzeri, W.; Briatico-Vangosa, F.; Castiglione, F.; Mele, A. Hydrophobic eutectogels: a new outfit for non-ionic eutectic solvents. Mater. Today Chem. 2023, 29, 101402. https://doi.org/10.1016/j.mtchem.2023.101402.
• Abranches, D.O.; Coutinho, J. A. P. Type V deep eutectic solvents: Design and applications. Curr. Opin. Green Sustain. Chem. 2022, 35, 100612. https://doi.org/10.1016/j.cogsc.2022.100612.
• Riva, L.; Dotti, A.; Iucci, G.; Venditti, I.; Meneghini, C.; Corsi, I.; Khalakhan, I.; Nicastro, G.; Punta, C.; Battocchio, C. Silver Nanoparticles Supported onto TEMPO-Oxidized Cellulose Nanofibers for Promoting Cd²⁺ Cation Adsorption. ACS Appl. Nano Mater. 2024, 7, 2401–2413. https://doi.org/10.1021/acsanm.3c06052.
• Fiorati, A.; Grassi, G.; Graziano, A.; Liberatori, G.; Pastori, N.; Melone, L.; Bonciani, L.; Pontorno, L.; Punta, C.; Corsi, I. Eco-design of nanostructured cellulose sponges for sea-water decontamination from heavy metal ions. J. Clean. Prod. 2020, 246, 119009. https://doi.org/10.1016/j.jclepro.2019.119009.
• Riva, L.; Nicastro, G.; Liu, M.; Battocchio, C.; Punta, C.; Sacchetti, A. Pd-Loaded Cellulose NanoSponge as a Heterogeneous Catalyst for Suzuki–Miyaura Coupling Reactions. Gels 2022, 8, 789. https://doi.org/10.3390/gels8120789.

2.9. Impact of Storage on the Structure Stability of Starch-Based HPP Hydrogels Loaded with Natural Extracts

• Katerina Koshenaj and Giovanna Ferrari

¹ 

Department of Industrial Engineering, University of Salerno, 84084 Fisciano, Italy

² 

ProdAl Scarl, University of Salerno, 84084 Fisciano, Italy

Starch-based hydrogels have garnered significant interest in recent years due to their potential applications in various fields. Their characteristic stable structure enables functionalization, allowing their use as smart carriers of the bioactive compounds of natural extracts. In this study, the physical stability of starch-based hydrogels loaded with natural extract produced via high-pressure processing (HPP) was evaluated. For this purpose, stability measurements, including swelling power, texture, pH, and organoleptic properties, were determined at various time intervals during storage at 5 °C and 25 °C. Hydrogels were developed using tapioca starch, which contains approximately 20.2% amylose. Tapioca starch was suspended in distilled water to prepare a 20% (w/w) suspension containing 2% (w/w) natural extract. The mixture was then subjected to high-pressure processing (HPP) at 600 MPa for 15 min to induce starch gelatinization and facilitate hydrogel formation. The results showed that during storage, a decrease was observed in swelling power from 1.35 to 0.28 g/g, indicating a reduction in the hydrogel’s ability to retain water, likely due to the structural rearrangements of polymer chains. Additionally, texture analyses revealed an initial decrease in hardness, cohesiveness, and springiness values at 15 days, followed by their increase after 30 days. These changes may be related to hydrogel reorganization, where initial relaxation reduces texture properties but longer-term polymer chain rearrangement or crosslinking enhances stability. Furthermore, changes in color parameters (L*, a*, and b*) suggest ongoing chemical transformations within the hydrogel matrix. Throughout the storage period, pH values remained stable at approximately 5, indicating limited acid–base interaction within the hydrogel system. Based on these findings, it can be concluded that more research is warranted to clarify molecular mechanisms and optimize release behavior for targeted nutraceutical and functional food applications.

2.10. Influence of the Dimethylsulfoxide–Water Mixtures on the Properties of Poly(Vinyl alcohol) Cryogels

• Olga Yu. Kolosova, Lada V. Barannikova and Vladimir I. Lozinsky
• A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilov Street 28, Building 1, 119334 Moscow, Russia

Introduction.

Poly(vinyl alcohol) cryogels (PVACGs) are the noncovalent macroporous gels formed as a result of freeze–thaw processing of concentrated PVA solutions. Such cryogels are widely used as biomedical materials due to their mechanical durability, biocompatibility and also viscoelastic properties similar to those of soft biological tissues.

In some cases, the application of PVACGs is limited by the yet insufficient rigidity of these materials. There are several ways to enhance the physico-mechanical properties of PVACGs, e.g., by increasing the initial polymer concentration, by inserting kosmotropic additives, by performing additional “freezing–thawing” cycles. We suggested another decision for increasing the elasticity of PVACGs by their treatment with water-DMSO mixed solutions.

Methods.

PVACGs were prepared by the “freezing–thawing” technique originating from the 100 g/L aqueous solutions of this polymer that have been frozen and incubated at −20 °C for 12 h. Furthermore, the temperature was raised to 20 °C at the rate of 0.03 °C/min. The resultant samples were than saturated with the water–DMSO mixed solutions of different volumetric ratio: 100/0, 75/25, 50/50, 25/75 and 0/100. Following this, Young’s modulus and the fusion temperature values of the resultant cryogels were measured.

Results.

It was shown that the rigidity grew with an increase in DMSO share in mixed solutions. In addition, the highest gel strength and heat endurance were reported for PVACGs saturated with the 50/50 (v/v) water–DMSO mixture. Young’s modulus increased by ~30 times (up to 235 ± 4 kPa) compared to the PVA cryogel (7.5 ± 0.6 kPa) prepared from the aqueous polymer solution. After rinsing “saturated” cryogels with pure water, their rigidity decreased (till 79 ± 2 kPa), but not critically so the high rigidity of PVA cryogels was preserved. Tf values of the corresponding samples were as follows: 92.6 ± 0.9 °C and 77.8 ± 0.8 °C.

Conclusion

The results of this study suggest that these materials based on such PVA cryogels could be of interest in various areas of application.

2.11. Light-Crafted Landscapes: Maskless Photosculpting of Hydrogels

• Mirko D’Urso ¹, Maaike Bril ¹, Mario Prejanò ², Matteo Costantini ³, Livia Angeloni ¹ and Nicholas Kurniawan ¹

¹ 

Biomedical engineering, Technische Universiteit Eindhoven, 5612 AE Eindhoven, The Netherlands

² 

Department of Chemistry and Chemical Technologies, University of Calabria, Cosenza, Italy

³ 

Department of Chemistry, Scripps Research, La Jolla, CA, USA

Introduction: Engineering physiologically relevant cell culture substrates requires decoupling multiple environmental cues, such as substrate stiffness and surface topography. Existing hydrogel patterning approaches are limited by complex fabrication, inflexible design space, and feature collapse on soft substrates. Here, we introduce a maskless, contact-free UV-sculpting technique that enables fully programmable microscale topographies (from 2 µm to DMD dimensions as the limit) directly onto a wide range of hydrogels, both synthetic (e.g., pAA, pNIPAM, PEG) and natural (GelMA, gelatin), with tunable resolution and topographical amplitude using digital designs and adjustable UV exposure or photoinitiator concentration.

Method: This approach leverages a digital micromirror device (DMD) to project any grayscale mask pattern onto hydrogel surfaces pre-treated with a photoactivator. Within minutes, spatially defined chemical modifications induce sculpting with micrometric fidelity. Feature height or depth (z-scale) can be precisely controlled by varying technique parameters, enabling rapid exploration of design structure relationships across hydrogel properties and physical cues.

Results: As representative benchmarks, GelMA exhibits extrusions of 2.877 ± 0.405 μm and pNIPAM 2.140 ± 0.426 μm, while pAA and PEG show invaginations of 0.117 ± 0.050 μm and 0.286 ± 0.043 μm, respectively, under standard exposure, and GelMA height scales with dose up to 1500 mJ/mm². Design flexibility is demonstrated with arbitrary shapes and grayscale gradients faithfully reproduced on hydrogels with stiffnesses from ~1.6 to 200 kPa, enabling independent tuning of topography and mechanics.

Conclusions: This technology provides a fast (5 min fabrication), digital, versatile, and high-throughput platform for generating multi-cue hydrogel substrates. The ability to independently tune mechanical and topographical parameters enables systematic studies in more physiologically relevant microenvironments. Future applications could extend to dynamic platforms, further enhancing spatiotemporal control over cell material interactions.

2.12. Nanofibrous Hyaluronic Acid/Gelatin Methacrylate Hydrogels Enhance Cartilage Regeneration

• Ali Mahnavi, Arjan Atwal, Ava Carroll, Ying Yang and Pooya Davoodi

¹ 

School of Allied Health Professions and Pharmacy, Keele University, Staffordshire ST5 5BG, UK

² 

Guy Hilton Research Centre, School of Life Science, Keele University, Staffordshire ST4 7QB, UK

Introduction Various forms of hyaluronic acid (HA)-based hydrogels are widely utilized in cartilage tissue engineering due to their intrinsic bioactivity, biocompatibility, and anti-inflammatory properties. However, the high viscosity of HA solutions limits their processability into fibrous structures that mimic the nanofibrous nature of the hyaline cartilage extracellular matrix. To address this, gelatin is often incorporated to improve electrospinnability while simultaneously providing bioactive cell adhesion motifs and enhanced mechanical properties. In this study, a hyaluronic acid methacrylate/gelatin methacryloyl nanofibrous hydrogel was developed to mimic native ECM architecture and promote chondrogenic activity for cartilage regeneration.

Materials and Methods HA (200–500 kDa) and gelatin were methacrylated, achieving degrees of modification of approximately 18% and 60%, respectively, as confirmed by NMR. Lyophilized HAMA (1, 1.5 and 2% w/v) and GelMA (5, 7.5 and 10% w/v) were dissolved in hexafluoroisopropanol and assessed using the Box–Benkhen design of experiments model combined with rheological analysis to identify suitable concentrations and optimize electrospinning parameters. The optimized formulations were mixed with Irgacure 2959, electrospun into mats (~10 mm × 10 mm at ~2 mm thickness), and UV-crosslinked following immersion in pure ethanol. After crosslinking, the mats were rinsed with PBS and prepared for cell culture.

Results and Discussion SEM images showed the morphology of nanofibers, with diameters of approximately 300 nm for low-HAMA/high-GelMA formulations, whereas higher HAMA content resulted in thicker fibers in the 400–600 nm range. Confocal microscopy demonstrated the stability of mats for at least 21 days and high chondrocyte viability (>80%), indicating the absence of cytotoxic residues. Finally, GAG/DNA quantification and immunofluorescence staining confirmed the expression of type II collagen and aggrecan, resembling native hyaline cartilage.

Conclusion The results indicate that the HAMA/GelMA fibrous hydrogel represents a promising strategy for cartilage tissue engineering by combining the bioactivity of HAMA with the mechanical and cell-interactive properties of GelMA.

2.13. Phenylalanine-Based Low-Molecular-Weight Gelators: Synthesis, Supramolecular Characterization and Multicomponent Gelation

• Edgard Alejandro Rivas ^1,2 and Pablo Hector Di Chenna ^1,2

¹ 

Department of Organic Chemistry, Faculty of Exact and Natural Sciences, University of Buenos Aires, Buenos Aires C1428EGA, Argentina

² 

UMYMFOR-Faculty of Exact and Natural Sciences, CONICET-University of Buenos Aires, Buenos Aires C1428EGA, Argentina

L-Phenylalanine (Phe), a neutral and nonpolar essential amino acid, serves as a key building block for supramolecular assemblies. Several low-molecular-weight gelators (LMWGs) containing Phe have been developed, with potential applications in different areas such as drug delivery, tissue engineering, and oil spill recovery. Similarly, vicinal dialkylamides have also demonstrated LMWG-forming capabilities, being promising materials for future research and development. In this context, the study of potential gelators was carried out with the synthesis of four Phe derivatives using 4,5-bromo-1,2-phenylenediamine (BPD) or (1R,2R)-(−)-1,2-diaminocyclohexane (DAC) as scaffolds. N-tert-butoxycarbonyl (Boc)-protected Phe was reacted with BPD or DAC (2:1 molar ratio) to yield BPD-1 and DAC-1, respectively. Subsequent deprotection afforded BPD-2 and DAC-2. The gelation ability of the synthesized compounds was tested in a range of solvents by means of the inverted test tube method. Minimum gelation concentration (MGC) and sol–gel temperature (Tg) were determined for the resulting gels. Additionally, gels were characterized morphologically (SEM), rheologically, and by circular dichroism (CD) spectroscopy at low concentrations. Although not all derivatives prepared could form any gels in common solvents, BPD-1 was found to produce stable gels in carbon tetrachloride, whereas DAC-2 generated an unstable gel in tetrahydrofuran. A multicomponent stable gel in carbon tetrachloride (M1BDP-1) was also achieved by combining BPD-1 with a previously reported LMWG with the same scaffold. SEM revealed fibrous three-dimensional network structures composed of fibers in BPD-1 and M1BDP-1 xerogels. Also, CD spectra display signals that suggest chiral supramolecular aggregation in BDP-1 gels. The L-Phenylalanine-based gelator BPD-1 can form stable physical gels on its own, as well as multicomponent gels with a structurally related gelator through a co-assembly process mediated by amide hydrogen bonds. The results indicate that combining L-Phenylalanine with known LMWG fragments can yield new gelating derivatives, highlighting their potential for functional material design.

2.14. State Diagrams for Binary Monoglyceride Mixtures

• Maria Eugenia Charo-Alvarado and Jorge Fernando Toro-Vazquez
• Faculty of Chemical Sciences, Autonomous University of San Luis Potosí, San Luis Potosí 78240, Mexico

Organogels are a unique type of gel formed by trapping an organic solvent within a supramolecular network. In a system like this, a three-dimensional structure occurs from the spontaneous self-assembly of low-molecular-weight gelator molecules (typically 3000 Da); this usually happens at temperatures below the solubility limit of the gelator in the chosen solvent (i.e., mineral or vegetable oil). Monoglycerides (MGs) have been previously studied and recognized for their ability to act as organogelator molecules. In the present study, state diagrams were constructed for binary mixtures of 1-stearoyl glycerol (C18) with 1-myristoyl (C14), 1-palmitoyl (C16), or 1-monobehenin glycerol (C22) in both vegetable and mineral oils. In all cases, the total monoglyceride (MG) concentration was constant at 8% (wt/wt) while varying the molar ratios of the components. Across all systems, a mixed lamellar (Lα) phase was observed, with the transition temperature not affected by changes in the C18 molar fraction, regardless of oil type or MG pairing. On the other hand, the sub-α crystalline phase showed a clear eutectic point at a specific MG molar fraction common to both oils for each MG pair. This eutectic composition might suggest that the disparity in alkyl chain lengths within the lamellar structures led to inefficient molecular packing compared to the compositions outside the eutectic range. MG oleogels formed at these eutectic compositions demonstrated significantly higher elasticity (G′ at 5 °C ≈ between 150 × 10³ and 690 × 10³ Pa) than those formed at other ratios. This behavior is attributed to the sub-α phase’s disordered packing, which likely facilitates greater oil entrapment within the gel network. The results highlight specifically that reduced chain packing efficiency at the eutectic point correlates with improved oil retention and mechanical strength, offering insights into optimizing gel formulations using MG binary systems in various oil media.

2.15. Structurally Stable Aerogel from Marine Biopolymers for the Functional Delivery of Virgin Fish Oil

• Bambang Riyanto, Rusty Rosalina Simatupang, Wini Trilaksani and Wahyu Ramadhan
• Department of Aquatic Product Technology, Faculty of Fisheries and Marine Science, IPB University, Bogor 16680, Indonesia

Virgin fish oil (VFO) is a high-quality source of omega-3 polyunsaturated fatty acids, particularly EPA and DHA, which offer significant health benefits. However, its application remains limited due to poor oxidative stability and undesirable sensory characteristics. Aerogel-based oleogelation presents an innovative non-thermal approach to address these challenges by forming a semi-solid structure that protects bioactive compounds while enhancing formulation flexibility. This study aimed to develop and optimize a marine biopolymer-based aerogel with superior structural capacity for VFO delivery using the Response Surface Methodology (RSM). Optimization was performed using a Box–Behnken experimental design. Three marine biopolymers—κ-carrageenan (0.5–3.0% w/v), chitosan (0.5–4.0% w/v), and gelatin (2–15% w/v)—were evaluated based on two key responses: gel fraction and swelling ratio. The optimized hydrogel was then freeze-dried to produce aerogel. Characterization was conducted using Scanning Electron Microscopy (SEM) for pore morphology, Brunauer–Emmett–Teller (BET) analysis for surface area, Differential Scanning Calorimetry (DSC) for thermal stability, and rheological analysis (frequency sweep) to evaluate oil absorption capacity and viscoelastic behavior. The optimal formula consisted of 0.90% κ-carrageenan, 0.5% chitosan, and 2.02% gelatin, resulting in a gel fraction of 54.50% and a swelling ratio of 23.07%. The resulting aerogel exhibited a mesoporous structure (3–7 nm), a specific surface area of 21.87 m²/g, and an oil absorption capacity of 17.2 g/g. DSC analysis revealed a thermal phase transition peak at 114.2 °C and an enthalpy of 80.54 J/g. Rheological testing showed dominant elastic behavior (G′ > G″, tan δ 1), indicating strong mechanical stability. The formulated marine biopolymer-based aerogel proved effective as a structurally and thermally stable VFO delivery system. This innovation shows strong potential for application in functional food products and supports the use of sustainable, clean-label marine-derived materials.

2.16. Synthesis of Chitosan–Alginate–Gelatin Aerogel Using Freeze Drying and Dehydrator Techniques as a Matrix for Virgin Fish Oil-Based Oleogel

• Bambang Riyanto, Natasya Aura Nur Fadillah, Wini Trilaksani and Wahyu Ramadhan

¹ 

Department of Aquatic Product Technology, Faculty of Fisheries and Marine Sciences, IPB University, Bogor 16680, Indonesia

² 

Center for Coastal and Marine Resources Studies (PKSPL), International Research Institute for Maritime, Ocean and Fisheries (i-MAR), IPB University, Bogor 16127, Indonesia

³ 

Aquatic Gels for Future Advanced Materials and Technologies Research Unit, IPB University, Bogor 16680, Indonesia

Omega-3 fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are essential components that play a crucial role in maintaining cardiovascular health, brain function, and neurological development; however, their consumption through fish oil faces challenges such as low solubility in aqueous matrices, oxidative instability, and an undesirable odor. Oleogelation using porous aerogels is considered a promising approach to enhance the stability and bioavailability of fish oil. This study aims to develop and evaluate dried aerogels based on chitosan, alginate, and gelatin as templates for the synthesis of fish oil oleogels, as well as to compare the effects of two drying methods on the structure and oil absorption capacity of the resulting aerogels. The methods focused on the preparation and characterization of chitosan–alginate–gelatin aerogels using freeze drying and dehydrator drying, as well as their ability to absorb virgin fish oil. Freeze-dried aerogels exhibited an open three-dimensional porous structure with an average pore size of 4.701 nm, whereas dehydrator-dried aerogels displayed a denser (closed-pore) structure with an average pore size of 4.450 nm. The freeze-dried aerogels demonstrated a high oil absorption capacity of 4.48 ± 0.21 g/g and an oil-binding capacity of 85.59 ± 3.73%, while the dehydrator-dried aerogels showed no detectable oil absorption and an oil-binding capacity that was negligible or close to zero.

2.17. Tuning the Viscoelastic Properties of Hydrogels to Mimic Prostatic Cancer Microenvironment

• Fabiana Cavarzan ¹, Matteo Cremonesi ¹, Giuseppe Guagliano ², Elisa Restivo ³, Francesco Briatico Vangosa ¹, Paola Chiarugi ⁴, Elisa Giannoni ⁴, Marta Iozzo ⁴, Giulia Gangarossa ⁴, Nora Bloise ³ and Paola Petrini ¹

¹ 

Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”, Polytechnic University of Milan, 20133 Milan, Italy

² 

Department of Molecular Biotechnology and Health Sciences, University of Turin, 10126 Turin, Italy

³ 

Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy

⁴ 

Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, 50134 Florence, Italy

Introduction

Three-dimensional hydrogels are increasingly being proposed¹ to mimic biological tissues and micromechanical environments, owing to their tunability. Understanding structure–composition relationships is crucial for tailoring their properties. A prostate cancer (PCa) model was developed using an internally crosslinked² alginate/gelatin hydrogel, designed to mimic the micromechanical environment and optimized for bioprinting with human PCa cells.

Methods

Hydrogels were prepared by sequentially mixing solutions/suspensions in 22Rv1 culture medium (final composition of 2% w/v gelatin, 6% w/v alginate, 0.7% w/v CaCO₃, 3.74% w/v GDL, and 3 × 10⁶ 22Rv1 cells/mL). Hydrogels were then covered with an equal volume of buffered medium. Frequency sweep tests were performed at 20–0.1 Hz at 20 °C, 37 °C, and 50 °C using a rotational rheometer. Gelation time was evaluated by time sweep tests.

Results

The hydrogel formed a semi-IPN showing in frequency sweep tests higher G″ at 20 °C and no G′ variations upon temperature changes. The timing of the medium addition (t_add) was used to control the viscoelastic properties. At 37 °C, 24 h after crosslinking onset, with t_add of 60 min, G′ reached 5.5 kPa (at 1.05 Hz), within the PCa stiffness range (5–10 kPa)³, and G″ was 240 Pa. Printability was a priori assessed by rheological analyses and then with a pneumatic 3D bioprinter^2,4. The best performance (printability coefficient 1.17) was obtained 30 min after crosslinking onset, with a 25G conical nozzle, 10 mm/s speed, and 70 kPa pressure. After 72 h, cell viability and metabolic activity increased compared to 1 h incubation (slightly below 2- and 1.5-fold, respectively). The initial pH (~6.5) gradually reached neutrality within 2 h (t_add 60 min; one medium change after 1 h).

Conclusions

Our study shows how composition and experimental parameters influence the properties of an alginate/gelatin hydrogel, providing a versatile approach for advanced 3D models and other hydrogel-based systems.

3. Session 3: Gels in Agriculture and Food

3.1. Development of Cottonseed Oil–Carnauba Wax–Pectin Emulsion Gels as Innovative Fat Replacers in Processed Meat Products

• Sudipta Talukder, Lina Casale Aragon Alegro and Roberta Claro Da Silva
• Department of Family and Consumer Sciences, North Carolina A&T State University, Greensboro, NC 27411, USA

Currently, fat substitutes using unsaturated oils and emulsifiers are limited, particularly due to thermal instability at processing temperatures above 85 °C, which results in emulsion breakdown, phase separation, and loss of functionality. Our objective was to develop and characterize novel emulgels consisting of cottonseed oil structured with carnauba wax (10% w/w of oil) and pectin (0–10% w/w of oil) as healthy alternative fats for meat products. Emulgels were prepared by mixing heated cottonseed oil–carnauba wax oleogel with glycerol monostearate (2% w/w) containing pectin solutions (0, 2%, 4%, 6%, 8% and 10% concentration). Processing was achieved by controlled temperature processes (oleogel preparation at 85 °C, dehydration at 50 °C to 25–28% humidity) followed by a subsequent 24-h stabilization process at 4 °C. The systems were evaluated by differential scanning calorimetry, rheology, polarized light microscopy, and oil binding capacity. Even at low concentrations of pectin, onset of melting was delayed. In addition, low concentrations of pectin also improved the viscoelastic characteristics of the emulsions. The oil-binding capacity of the emulsions decreased when 4% or more pectin was added. The 2% pectin emulgel exhibited a high onset temperature (101.71 °C) and OBC (95.76%), as well as an improved storage modulus (125.74 kPa), indicating very good structural strength. Cottonseed oil–carnauba wax–pectin emulgels represent an innovation in sustainable fat replacement technology for processed meat. Looking into the microstructure of the emulgels, it is evident that the crystalline structure is maintained with the addition of 2% pectin, resulting in improved rheological properties while preserving gel stability compared to the control (no pectin). However, when pectin is added at levels higher than 2%, a decrease in the bright crystalline structures is observed. This novel approach has the potential to provide the food industry with an innovative solution for developing healthier processed meat products while addressing consumer demands for natural and sustainable ingredients.

3.2. Active Edible Coatings for Fresh Food as a Suitable Alternative to Plastic

• Beatriz Gutiérrez Portal ¹, Andrés Felipe Vélez Linares ¹, Leire Ruiz Rubio ^1,2, Leyre Pérez Álvarez ^1,2 and Estibaliz Hernaez Laviña ¹

¹ 

Innovative Macromolecular Materials (Imacromat), Department of Physical Chemistry, University of the Basque Country UPV/EHU, 48940 Leioa, Spain

² 

Basque Center for Materials, Applications and Nanostructures, UPV/EHU Science Park, 48940 Leioa, Spain

Nowadays, it is well-known that plastic is a global problem that affects both the environment and human health. For this reason, different institutions encourage the reduction of plastic use. One way to reduce single-use plastic is to use edible gels. These edible coatings serve the purpose of protecting and preserving fruit. This way, the use of petroleum-based plastic will no longer be necessary.

To determine the effect ofedible coatings, fresh tomatoes were used as samples. These were covered with different edible coating solutions, and their evolution was analysed over time. The effects of the concentration of active compounds were studied at 0.5%, 1.0%, and 1.5% in 0.5% chitosan solutions, crosslinked with a subsequent immersion in sodium triphosphate pentabasic solution, with the active compounds being carvacrol, curcumin, and polyphenolic extracts obtained from strawberries and red algae (Gelidium sesquipedale). Also, coatings were formulated with β-cyclodextrin inclusion complexes of curcumin and carvacrol. Both complexes were characterised by FTIR spectroscopy to confirm their formation. The tomatoes were stored in a refrigerator at 4 °C.

Through visual analysis, it was determined that the tomatoes coated with curcumin did not show mould proliferation. In contrast, those coated with carvacrol developed mould. In addition, different decomposition processes were observed depending on the type of active compound used. Compared to the control tomatoes, it was noticed that the coatings delayed their decomposition, with the β-cyclodextrin complexes resulting in the longest-lasting tomatoes, followed by the polyphenolic compounds at higher concentrations.

Through this work, the importance of the composition of the coatings in protecting and preserving fresh foods like tomatoes, as well as the influence of the proportions of the active compounds, was determined. Nevertheless, it is advisable to carry out further studies, such as biological analyses, to determine the chemical interactions of coatings with food.

3.3. Advancing Sustainable Agri-Food Systems with Biopolymer Hydrogels: From Soil Enhancement to Edible Applications

• Abid Hussain
• Department of Biological Sciences, Thal Univeristy Bhakkar, Bhakkar 30000, Punjab, Pakistan

Biopolymer hydrogels are synthesized from natural polymers such as chitosan, alginate, cellulose, and starch, each contributing distinct functional properties. Chitosan provides antimicrobial and film-forming abilities, alginate ensures ionic crosslinking and gel stability, and cellulose enhances structural reinforcement and water retention, while starch offers biodegradability and tunable swelling capacity, collectively making these hydrogels promising sustainable materials for agri-food systems. These hydrogels are synthesized through cross-linking strategies such as chemical grafting and ionic interactions, which impart tailored network architectures. As a result, they exhibit remarkable water retention (up to 400× their dry weight) and controlled-release capabilities, positioning them as effective materials for soil conditioning and nutrient delivery. Recent studies have demonstrated the efficacy of biopolymer hydrogels in agriculture, particularly in improving soil and nutrient management. For example, crosslinked xanthan guar gum hydrogels sustained soil water retention across 12 wet and dry cycles, while starch polyacrylamide hybrids increased nitrogen use efficiency in wheat by 20 to 30 percent and reduced fertilizer leaching. In food systems, chitosan–thyme oil hydrogel coatings extended the shelf life of fresh-cut fruits by 3–5 days by mitigating moisture loss and oxidative spoilage, and alginate-chitosan encapsulation boosted probiotic survival by 2–3 log units during digestion. Environmental benefits include a 30–50% reduction in greenhouse gas emissions compared to synthetic polymers, alongside biodegradability and waste valorization potential (e.g., dairy by-products acid whey used in hydrogel synthesis). Future research should prioritize large-scale field trials to validate long-term agroecological impacts and optimize cost-effective production methods for global scalability. Despite challenges like variable mechanical strength, advancements in stimuli-responsive (pH/temperature-sensitive) hydrogels and precision agriculture integration promise to further optimize their performance. Collectively, biopolymer hydrogels represent a transformative approach to sustainable agri-food systems, balancing ecological and economic demands while aligning with global sustainability goals.

3.4. Characterization of Mozzarella Cheese Analogue with Reduced Saturated Fats Using Soybean Oil and Beeswax Oleogels

• Zoha Ali and Farzana Siddique
• Institute of food science and nutrition, University of Sargodha, Sargodha 40100, Pakistan

The excessive consumption of saturated fats has been linked to an increased risk of non-communicable diseases such as cardiovascular disease and type II diabetes. As a result, consumers increasingly seek healthier food options, prompting the food industry to explore innovative ingredients that enhance nutrition and functionality. Oleogels, structured gels made from plant-based oils, are emerging as promising alternatives to traditional solid fats in dairy products due to their ability to improve fat profiles by increasing unsaturated fatty acids and reducing saturated fats. Soybean oil was structured into oleogels with varying yellow beeswax concentrations and evaluated as a solid fat alternative for low-saturated-fat mozzarella cheese analogues. Oleogels showed reduced sensitivity to temperature changes compared to shortening. Replacing shortening with oleogels resulted in cheese samples with harder and more cohesive textures. Moisture content significantly varied across treatments (p0.05), increasing with oleogel concentration: the control sample (T0) had 53.00% ± 0.007, while T3 had 57.32% ± 0.004. Microscopic analysis reveals that oleogel-based cheese displayed a dense droplet aggregation similar to the control, with increased beeswax content enhancing droplet density and crystal network formation. Textural analysis demonstrated that no significant differences were observed in adhesiveness, springiness, or cohesiveness. However, hardness values were significantly different (p0.05), increasing from 7.09 ± 0.16 in T0 to 9.97 ± 0.11 in T3. Fracturability also showed a significant difference (p0.05), with T0 at 6.89 ± 0.11 and T3 at 9.50 ± 0.40. The SFA/USFA ratio significantly decreased across all treatments (p0.05), with T1 at 0.0122 ± 0.004 and T3 at 0.0289 ± 0.002, compared to 0.79 ± 0.02 in the control. Meltability slightly decreased from 83.75 mm in the control (T0) to 81.23 mm in the 4% oleogel sample (T1). L* values increased significantly (p0.05) with the oleogel, indicating a lighter appearance, while a* values remained consistent. b* values increased with oleogel concentration. This research provides insight into the possible uses of oleogels, a milk fat substitute with useful characteristics, in the production of mozzarella cheese.

3.5. Development and Characterization of Oleogel Foams Based on Monoglyceride and Lecithin in Vegetable Oil

• Marisol Dávila-Martínez, Jorge Fernando Toro-Vazquez and Mayra Aguilar Zárate
• Faculty of Chemical Sciences, Autonomous University of San Luis Potosi, San Luis Potosi 78210, Mexico

Low-fat food production, the delivery of pharmaceuticals, and cosmetics development have led to research and innovation in gas-in-oil systems (i.e., oleofoams) from vegetable-based formulations. The objective of this work was to develop stable foams based on monoglyceride (MG) and lecithin (LC) oleogels in vegetable oil for applications in the above systems. Four formulations were evaluated at a fixed MG concentration of 4% with 0%, 0.25%, 0.5%, and 1% (w/w) of LC. Foaming ability was calculated as the overrun percentage; the thermal and mechanical properties were characterized by DSC and rheology, respectively; PLM identified the microstructure; all determinations were performed during storage at 0, 7, 15, and 30 days at 15 °C. The results showed that the foam volume doubled the initial volume of the oleogel (i.e., 10 mL to 20 mL), remaining this way for up to 7 days. During this period, 2.5 to 3 mL of oil volume had been released. The foam remained stable for up to 30 days without collapsing. The melting temperature (TM) of each formulation studied was statistically the same after 7 days until 30 days of storage (p > 0.05); the TM was higher when the concentration of LC increased in the formulation. The foam rheology increased during storage (e.g., 4%MG+0.25%LC at 0 days: 953 Pa ± 156, 7 days 20,240 Pa ± 1386, 30 days: 27,580 Pa ± 3167; 4%MG + 1%LC at 0 days 288 Pa ± 66, 7 days 14,330 Pa ± 156, 30 days 21610 Pa ± 382) as the loss oil was released slowly. The foam consisted of a mixed network of MG-LC crystals and air droplets, which were also stable over time. This allowed us to propose an alternative material based on a stable oleofoam of MG-LC for the structuration and/or formulation of food, cosmetic, or pharmaceutical systems.

3.6. Development of Fresh Pasta with Carob–Xanthan Hydrogel and Acorn Flour: A Promising Gluten-Free and Egg-Free Alternative

• Francesca Vurro, Alexandra-Mihaela Ailoaiei, Davide De Angelis, Giacomo Squeo, Antonella Pasqualone
• Department of Soil, Plant and Food Science, University of Bari Aldo Moro, Via Amendola, 165/a, 70126 Bari, Italy

Pasta is a staple food that is deeply rooted in Italian gastronomic and cultural traditions, often serving as a symbol of tradition and regional identity. In its fresh form, the dough of some pasta types is enriched with eggs, enhancing nutritional, technological and sensory profiles.

The growing demand for plant-based, allergen-free, and environmentally sustainable products is driving innovation in food formulation. However, such products—particularly gluten-free variants—often present structural and sensory limitations, which are typically overcome through the use of complex mixtures of additives. This practice is in contrast to the trend to reduce ingredient lists.

In this context, the present study aims to develop a gluten-free and egg-free pasta formulation that meets nutritional, technological and environmental needs. A plant-based hydrogel composed of carob seed flour and xanthan gum was utilised to mimic the viscoelastic properties of gluten and eggs. An alternative gluten-free flour, obtained by milling of acorns, was proposed as a total or partial substitute for rice flour, offering a strategy to valorize this neglected ingredient.

The ratio of gel to flour was optimized through preliminary tests. The rheological, physicochemical and nutritional properties were evaluated.

The incorporation of the hydrogel resulted in improved dough elasticity and texture, while the use of acorn flour contributed to a darker color, enhanced sweetness, higher lipid and fiber content, and a notably higher phenols and antioxidant activity.

In conclusion, the present study highlights two key results: the effectiveness of plant-based hydrogels as structural and functional agents in gluten-free and egg-free fresh pasta, and the nutritional and environmental benefits of using acorn flour as an alternative to conventional gluten-free flours.

3.7. Efficacy of Chitosan and Alginate-Based Gels for Inhibition of Botrytis Cinerea and Penicillium Expansum in Strawberries and Blueberries

• Mian Muhammad Ahmed ¹, Muqaddas ², Muhammad Asim ³, Muhammad Atiq Ashraf ³, Saqib Ayyub ⁴, Muhammad Wajahat Rasool ⁵ and Pan Zhiyong ³

¹ 

College of Life Science and Technology, Tarim University, Alar 843300, China

² 

College of Food Science and Engineering, Tarim University, Alar 843300, China

³ 

National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan 430070, China

⁴ 

Institute of Horticultural Sciences, University of Agriculture, Faisalabad 38000, Pakistan

⁵ 

Institute of Agronomy, Bahauddin Zakariya University, Multan, Pakistan

Introduction: Post-harvest fungal decay poses a major challenge to the berry industry, with Botrytis cinerea (gray mold) and Penicillium expansum (blue mold) being the primary pathogens that reduce fruit shelf life and marketability. The present study evaluates the effectiveness of chitosan- and alginate-based gel coatings, enriched with natural antimicrobial agents, in reducing fungal decay and maintaining quality in strawberries and blueberries. Methods: Chitosan (1–2%) and sodium alginate (1–2%) solutions were prepared, adjusted to optimal pH, and applied as coatings to freshly harvested fruits. Control samples were treated with water. All fruits were stored at 4 °C and 20 °C, and fungal decay, fruit firmness, and moisture loss were monitored over a 14-day storage period. Results: The results demonstrated that chitosan-based coatings significantly suppressed the growth of B. cinerea in strawberries, while alginate gels showed greater efficacy against P. expansum in blueberries, reducing decay incidence by 35–40%. Both coatings also reduced water loss and preserved fruit firmness compared to controls. Notably, the shelf life of treated fruits was extended by 4–5 days under both storage conditions. Conclusion: Chitosan- and alginate-based gel coatings represent a promising, eco-friendly alternative to synthetic fungicides for managing post-harvest fungal decay in berries. By forming protective barriers and incorporating natural antimicrobials, these coatings not only suppress pathogen development but also maintain fruit quality and reduce food waste. Further research focusing on formulation optimization, synergistic combinations of bioactive compounds, and large-scale application is recommended to facilitate their commercial adoption.

3.8. Emulgel Structured with Citrus Fiber as Potential Delivery System of Curcumin (Curcuma longa) for Food Application: Viscoelasticity Modelling, Morphology and In Vitro Diffusion Study

• Domenico Mammolenti ¹, Patrizia Formoso ², Francesca Romana Lupi ¹, Noemi Baldino ¹ and Domenico Gabriele ¹

¹ 

Department of Information, Modeling, Electronics and Systems, (D.I.M.E.S.) University of Calabria, Via P. Bucci, Cubo 39C, 87036 Rende, Italy

² 

Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Via A. Savino, Polyfunctional Building, 87036 Rende, Italy

Citrus fiber is recognized to be a structuring ingredient that can form particle hydrogels (in water) or emulgels (oil droplets entrapped in the water phase). Emulgels are used in a wide range of food applications, such as low-fat and low-calorie foods or food supplements, since they are particularly suitable for the delivery of bioactive molecules. In the present work, emulgels containing citrus fiber that are potentially suitable as a food supplement of curcumin were produced by high-speed homogenization and using two different edible oils: Miglyol^® 812N and rice oil (both at 0.4 w/w). The viscoelasticity of the emulgels and single phases (hydrogels and oil phases) was investigated by frequency sweep test in the linear region, and was previously determined by a stress sweep test. The consistency, in terms of complex shear modulus (G*), of both the hydrogel and emulgels increased more than linearly with increasing fiber fractions (from 0.020 w/w to 0.030 w/w), whereas the structuring degree, in terms of phase angle (δ), was almost independent of the fiber fraction. The addition of curcumin does not affect the viscoelasticity of oil phases based on either oil. The emulgel with rice oil showed higher G* than that containing Miglyol^® 812N, but they showed similar δ values. Rheological results for the emulgels were modelled using the weak gel model. The gel strength increases with increasing fiber fraction; network extension seems independent from fiber concentration. Curcumin does not change the consistency of emulgels, but it slightly decreases teir structure extension (δ moves from 5.5° to approximately 7.0°), According to in vitro diffusion studies, the diffused curcumin percentage (Cur%) at 24 h was 14.6% for the emulgel with Miglyol^® 812N, whereas for the emulgel with rice oil, it was 18.3%. These results can be considered promising for making future investigations attractive for the development of edible emulsions for food supplementation of curumin.

3.9. Improving Soil with Biopolymer Hydrogel: Better Soil Quality and Water Retention

• Qais Mohammed Al-Amri and Afrah Hamed Al-Shukaili
• Department of Soils, Water and Agricultural Engineering, College of Agricultural and Marine Sciences, Sultan Qaboos University, Muscat, Oman

Water scarcity in arid and semi-arid regions requires soil amendments that not only enhance moisture retention but are also biodegradable, locally sourced, and environmentally friendly. This study presents the development and evaluation of three biopolymeric hydrogel composites made from sodium alginate extracted from Sargassum spp., and functionally improved with frankincense (Boswellia sacra) extract and palm-derived biochar. A commercially available potassium polyacrylate hydrogel and research-grade acrylamide–acrylate copolymer were used as benchmarks for these natural formulations. A comprehensive evaluation of soil hydrogel interactions was conducted through RETC-modeled water retention curves, sequential drying-rewetting cycles, ImageJ crack morphology analysis, and post-treatment measurements of soil pH and electrical conductivity (EC). RETC modeling has shown that soil treatment increases saturated water content (θ) from 0.1170 (control) to 0.2679, with high pore uniformity (n = 4.05). On the contrary, COM remained only θs = 0.1313 despite its high drainage index (n = 5.0). R reached the highest θs = 0.4795, but with low pore uniformity (n = 1.63). Analysis of stenosis revealed soil treated with F. This represents 25% in COM and controls. Quantitative determination of the cracks indicates that COM developed 3.88–6.83% of surface cracks, where R was cracked, while the two soils F and F+B remained intact with 0% crack. Chemical analysis after two cycles of drying–rewetting showed that EC increased EC to 0.7 ds/m in COM, with F and F+B responsible for a threshold below salinity between 0.5 and 0.6 ds/m. The significance of matrix-specific hydrogel evaluation and the desorption stress dynamics specific to surface-applied superabsorbent are underscored by these results. This study provides a new path toward climate-resilient sustainable soil management systems in desert agriculture by managing the design of biodegradable polymers with capillary behavior and soil–water physics.

3.10. Modeling Sensory Acceptance Prediction Based on Texture Attributes and Physicochemical Properties in the Case Study of Dairy Sweet Gel (flan) and Plant-Based Milk Substitutes

• Regina Navarrete-González and Nelly Ramirez Corona
• Departamento de Ingeniería Química, Alimentos y Ambiental, Universidad de las Américas Puebla, Santa Catarina Mártir S/N, San Andrés Cholula 72810, Puebla, Mexico

The aim of this study was to formulate and optimize a gel-based tartlet by replacing egg protein with plant-based ingredients. Additionally, a mathematical model was proposed that correlates consumer acceptance data with measurable texture profiles and physicochemical properties.

The study established sensory acceptance as the target function for optimization, created from statistical design (DOE), using experimental data on mixtures and responses in terms of viscosity, density, colour delta, and pH, as well as texture profile in terms of hardness. Once the data was obtained, optimization was applied to find the firmest and most appealing texture. A Box–Behnken design was used to optimize the oil and protein content of each formulation. To replicate the egg-tartlet’s gel texture, 13 mixtures (such as corn, oats, rice, amaranth, chia seeds, chickpeas, soybeans, and almonds) were prepared, then heat-treated at 170 °C for 30 min. The optimal formula was a mixture of coconut cream (40%), almond-amaranth protein (25%), and corn starch (35%) on a wet basis.

The resulting texture was measured at 0.18 N ± 0.01 and the viscosity was measured at 35.7 cP ± 12, and the texture profile analysis included hardness, elasticity, chewiness, and masticability. The consumer preference data was used to study the control tartlet made with eggs and two plant-based versions. The consumer preference data was analysed using a discriminative test to identify whether the substitution approximated the desired texture. A semi-trained panel of 35 people who had received texture identification training evaluated texture, taste, and acceptability. Each panel member signed an informed consent form authorised by the institution’s ethics committee.

The statistically optimized formula was presented to the panel on a 9-point scale and a descriptive scale of intensity texture attributes. The panel accepted the plant-based gel-tartlet, but described its elasticity and chewiness as low-intensity attributes. The proposed correlation among textural attributes and sensory perception can be further utilized as a tool for formula development.

3.11. Novel Food-Grade Bigels Structured with Wax from the Native Stingless Bee (Scaptotrigona mexicana) and Canola Oil

• Zuemy Hernández-Nolasco, Mariana Inés Acateca-Hernández, Natalia Real-Luna and Aleida Selene Hernández-Cázares
• Innovación Agroalimentaria Sustentable, Colegio de Postgraduados, Texcoco 56264, Edo de México, Mexico

Introduction: Bigels (BGs) are biphasic systems combining oleogel (OG) and hydrogel (HG) networks and are emerging as promising fat replacers in food systems. In this work, food-grade BGs were developed using Scaptotrigona mexicana wax—a native stingless bee species of ecological and biocultural importance—as an oleogelation agent. Methods: The OG phase was formulated with S. mexicana wax and canola oil at a 10:90% (w/w) ratio, while the HG phase consisted of potato starch and κ-carrageenan (10:2% w/w). BGs were prepared at different OG:HG ratios—25:75 (BG1), 50:50 (BG2), and 75:25 (BG3)—and their physico-chemical, mechanical, structural, and microstructural properties were evaluated. Results: Oil holding capacity was highest in BG1 (86.46%) and significantly decreased with increasing OG proportion, reaching 64.98% in BG3, which also reduced moisture content (67.44–23.06%), pH (4.83–3.88), hardness (0.52–0.11 N), and viscosity (0.153–0.059 Pa·s). Regarding color, the L* value decreased from 48.3 to 26.6 and the b* value from 23.5 to 17.8 from BG1 to BG3, reflecting the natural brown hues characteristic of the wax. Different types of microstructures were identified: (O/W) in BG1, bicontinuous in BG2, and (W/O) in BG3. Electrical conductivity markedly decreased from 4.01 × 10⁻¹ mS/cm in BG1—indicating the HG as the continuous phase—to 5.9 × 10⁻⁶ mS/cm in BG3, attributable to the insulating nature of the OG phase. FTIR spectra exhibited characteristic peaks of the OG phase at 2918, 2852, 1740, 1462, and 721 cm⁻¹, with no evidence of new chemical interactions, suggesting physical integration determined by the OG:HG ratios. Conclusions: S. mexicana beeswax proved to be an effective oleogelator for developing stable food-grade OGs and BGs with tunable properties depending on OG:HG ratios, holding promise as fat replacers. Future research could enhance BG performance by incorporating polymers that improve HG phase stability.

3.12. Optimization of pH, Temperature, and Protein for Resistant Starch and Textural Properties of Corn Starch–Pea Protein Gels

• Andy G. Duchamp ^1,2, Damilare E. Jegede ¹, Bukola A. Onarinde ¹ and Samson A. Oyeyinka ¹

¹ 

School of Agri-Food Technology and Manufacturing, University of Lincoln, Holbeach PE12 7PT, UK

² 

École Supérieure d’Ingénieurs Réunion Océan Indien, Saint-Pierre, Réunion

The textural behaviour of starch–protein gels is critical for designing functional foods with enhanced resistant starch (RS) potential. This study explored the influence of heating temperature (75–100 °C), pea protein isolate concentration (5–20%), and pH (3–9) on the gelation properties of a corn starch–pea protein system. A Minitab-generated Box-Behnken experimental design produced 30 gel samples, and texture profile analysis (TPA) was used to measure hardness, cohesiveness, springiness, gumminess, chewiness, resilience, and adhesiveness. The results showed that pH was the most influential factor in enhancing RS formation, with acidic conditions (pH 3) leading to approximately 24.55% RS content in the gels. Conversely, increasing protein concentration tends to reduce RS levels, suggesting a possible inhibitory effect on starch retrogradation mechanisms. Temperature had a moderate effect on RS formation. Furthermore, higher processing temperatures (87.5–100 °C) significantly improved springiness, cohesiveness, and gumminess, indicating the formation of more structured and elastic gels. Protein concentration also influenced gumminess and springiness at elevated temperatures, while pH had a milder impact on textural attributes. Optimisation results tailored to maximise RS content with specific textural properties for specific food applications, such as set yoghurt, revealed a temperature of 100 °C, 5% protein, and a pH of 3, with a desirability score of 0.61. These findings highlight the critical role of formulation parameters in promoting RS formation and modulating texture, providing valuable guidance for the design of functional starch-based food systems. Future studies should apply the modified starch in food systems to assess the functionality and RS levels in model foods.

3.13. Poly(Vinyl alcohol) Cryogels as Carriers of Phytohormones

• Victoria Lee ¹, Olga Kolosova ², Nataliya Bystrova ³ and Vladimir Lozinsky ²

¹ 

Faculty of Chemical and Pharmaceutical Technologies and Biomedical Preparations, Dmitry Mendeleev University of Chemical Technology of Russia, Moscow, Russia

² 

Laboratory of Cryochemistry of Biopolymers, A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow, Russia

³ 

Homolytic Reactions Laboratory, A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow, Russia

Introduction

In recent years, hydrogel materials have seen increasing use in agriculture, especially for combating soil erosion and enhancing plant productivity.

Poly(vinyl alcohol) cryogels are physical macroporous heterophase gels formed by freezing polymer solutions, maintaining them in a frozen state, and then thawing them. PVA cryogels can serve as carriers of various biologically active substances, such as phytohormones that influence plant growth and development.

Methods

Auxins are a group of phytohormones that play a key role in regulating plant growth and development. These compounds are universal plant growth regulators that affect cell division, elongation, morphogenesis, and the formation and growth of plant roots. In this work, poly(vinyl alcohol) cryogels were obtained using the freeze–thaw method in the presence of auxins at different concentrations: indole-3-acetic acid and indole-3-butyric acid in nonprotonated and salts forms. For the obtained samples, elastic moduli and heat resistance were estimated, the dynamics of auxin’s release from the gel matrix into the aqueous environment were studied, and experiments on the biological activity of obtained materials were carried out.

Results

This study showed that poly(vinyl alcohol) cryogels formed with the described auxins additives retained their elastic and thermal properties. The release of substances into the aqueous environment from the gel matrix occurs without diffusion barriers. It was demonstrated that incorporating auxins into the polymer matrix of PVA cryogels does not lead to a change in their biological activity; specifically, rhizogenesis in plants is stimulated, leading to the formation of more roots and enhanced plant growth.

Conclusion

Thus, PVA cryogels with auxin additives represent a promising type of hydrogel that can be effectively used in agriculture to improve plants’ phytoproductivity.

3.14. Polysaccharide-Derived Hydrogel Matrix-Based Platform for Beverage Quality Monitoring

• Ashish Kapoor
• Department of Chemical Engineering, Harcourt Butler Technical University, Kanpur 208002, India

The detection of contaminants in beverages is essential to safeguarding consumer health and ensuring product quality. In this study, a polysaccharide-derived hydrogel matrix was developed as an eco-friendly sensing platform for the colorimetric monitoring of beverage quality. The hydrogel was fabricated under mild, green conditions using renewable biopolymers and incorporated with selective reagents capable of producing visible color responses upon interaction with target analytes. The hydrogel displayed excellent porosity and water retention capacity, enabling efficient diffusion of analytes and rapid colorimetric response. Distinct and reproducible color transitions were observed when the hydrogel matrix was exposed to BPA, a model contaminant. For quantitative assessment, color changes were captured using a smartphone camera and analyzed through digital image colorimetry. The platform demonstrated good sensitivity, with detection in the low micromolar range, and high reproducibility across multiple measurements. To validate real-world applicability, the system was tested with real beverage samples, including bottled consumables and drinking water. The sensor exhibited reliable performance, with consistent responses and minimal sample pretreatment requirements. The inclusion of a cellulose support enhanced the stability and handling of the hydrogel, further contributing to its practical usability. Overall, the polysaccharide-based hydrogel platform provides a sustainable, low-cost, and user-friendly approach for beverage quality monitoring. Its integration with smartphone-assisted analysis offers strong potential for portable and on-site contaminant detection.

3.15. Preparation and Investigation of Starch-Based Hydrogels Crosslinked with Citric Acid

• Zarina Taganbekova and Vadim Ivanovich Markin
• Institute of Chemistry and Chemical and Pharmaceutical Technologies, Altai State University, 61 Lenin Avenue, Barnaul 656015, Russia

Introduction. Polysaccharide hydrogels are of great interest due to their biocompatibility and environmental safety. Starch-based hydrogels modified with citric acid—a biocompatible crosslinker—form three-dimensional networks with controlled crosslinking and swelling. This work aims to synthesize and comprehensively study such hydrogels, evaluating their physicochemical properties and biotechnological potential.

Methods. Fourteen starch hydrogel samples were synthesized with citric acid concentrations from 2.4 to 42 mmol per kmol of starch, using a hydromodule of 50 and reaction times between 1 and 5 h. Key properties—including swelling degree, gel fraction, and sorption capacity for methylene blue (via UV–visible spectroscopy)—were measured [1]. Rheological behavior during synthesis was analyzed, and FTIR spectroscopy confirmed crosslinked network formation. Growth-stimulating activity was assessed via pre-sowing treatment of wheat seeds.

Results. Swelling degree ranged from 0.9 to 1.8 g/g, with gel fraction between 68 and 97%. The optimal synthesis time was 2 h at 2.5 mmol citric acid per kmol starch, where swelling reached 1.7 and plateaued with longer reaction times. The optimal sample sorbed methylene blue up to 0.89 mg/g. The dynamic viscosity quickly peaks at 0.027 Pa·s within 1.1–1.4 h and then gradually decreases due to structural changes. FTIR spectra showed intense bands at 1790–1650 cm⁻¹, indicating ester bond formation; band intensity increased with citric acid concentration, confirming higher crosslinking.

Growth stimulation varied by conditions: stems grew better in sandy soil, while root development and biomass were higher in Petri dish cultures. Hydrogel-treated seeds showed 10–25% greater germination than controls in both cases.

Conclusion. The developed hydrogels exhibit high swelling, stable gel structure, and enhanced sorption properties. They effectively stimulate plant growth and show promise for agritechnology applications, particularly pre-sowing seed treatment and soil moisture management.

3.16. Structuring Niger Seed Oil with Beeswax: Physicochemical, Structural, and Oxidative Stability Insights into Oleogel Formation

• Manisha and Punyadarshini Punam Tripathy
• Agricultural and Food Engineering Department, Indian Institute of Technology Kharagpur, West Bengal, India

Substituting saturated and trans fats with healthier lipid systems is an urgent requirement in food formulation, and oleogelation is a viable approach. This work utilised niger seed oil, a novel edible oil abundant in unsaturated fatty acids, which was structured using beeswax as an oleogelator. Oleogels were prepared using a magnetic stirrer at 400 rpm and 90 °C for 20 min until the beeswax was fully dissolved. The critical gelation concentration of beeswax was found at 3%, leading to the selection of formulations with 4% (BW4), 7% (BW7), and 10% (BW10) beeswax for physicochemical characterisation.

Physicochemical properties were strongly influenced by beeswax addition. The color parameters shifted with increasing wax concentration, with lightness (L*) increasing from 36.88 to 48.98, red to green (a*) changing from −2.03 to −2.52, and yellow to blue (b*) increasing from 7.52 to 15.98. Oil binding capacity improved from 93.22% to 98.92%, while hardness rose from 1.4 N (BW4) to 3.4 N (BW10). X-ray diffraction revealed enhanced crystallinity with higher wax levels, while FTIR spectra confirmed that the oleogel retained the chemical identity of the oil. All oleogels exhibited shear thinning behaviour and were best fitted to the Power law model (R² = 0.95–0.99). The addition of waxes resulted in an increased apparent viscosity of the oleogels. Increased wax levels enhanced the storage and loss modulus, making the gels rigid. It was observed that at higher wax concentrations, creep compliance decreased and recovery rates were enhanced. Oxidative stability tests indicated that although peroxide and p-anisidine values increased during 30 days of storage, higher wax concentration reduced oxidation compared to lower concentrations.

Overall, beeswax-structured oleogels successfully enhanced the functional and oxidative stability of niger seed oil, demonstrating their potential as sustainable fat alternatives in food applications.

3.17. Sustainable Marine Biopolymer Gels for Active, Biodegradable Film Formation

• Andrés Felipe Vélez Linares, Beatriz Gutiérrez Portal, Leire Ruiz Rubio, Leyre Perez Alvarez and Jose Luis Vilas Vilela

¹ 

Innovative Macromolecular Materials (Imacromat), Physic-Chemistry department, Basque Country University UPV/EHU, 48940 Leioa, Spain

² 

Basque Center for Materials, Applications and Nanostructures, UPV/EHU Science Park, 48940 Leioa, Spain

The accumulation of petroleum-based plastics in food demands sustainable, high-performance alternatives. Marine biomass supplies abundant polysaccharides (agar, alginate, carrageenan, and chitosan) and polyphenolic co-extracts that assemble into hydrogels and, upon drying, yield functional xerogel films. Here, “gel-derived” denotes films obtained by drying pre-formed gels (e.g., thermo-reversible agar networks) or by casting network-tailored matrices (methacrylation, β-cyclodextrin complexation) that display gel behavior upon hydration. Edible coatings lie outside the scope.

Beachcast macroalgae collected by tidal action were processed within 48 h. This initial phase used red algae (Gelidium sesquipedale); the workflow will extend to brown/green macroalgae and microalgae. Polysaccharides were recovered by alkaline pretreatment followed by hot-water extraction or by ultrasound-assisted maceration; phenolic fractions were obtained by ethanolic maceration and quantified by Folin–Ciocalteu. Agar, alginate, and chitosan were methacrylated. Films were prepared by first inducing gelation (agar sol–gel cooling; network setting in methacrylated alginate/chitosan) and then drying to obtain xerogel films. FTIR and DSC assessed structure/complexation; swelling probed rehydration.

Conventional agar extraction yielded 0.80 g from 5 g dry biomass, whereas ultrasound yielded 0.50 g. Total phenolics were low in algal extracts (0.0925 mg GAE·g⁻¹ dry biomass in an early batch; later protocol: 10.49 mg·L⁻¹) with excellent calibration (R² = 0.992). FTIR revealed intensified C–O and emergent C=O bands consistent with methacrylation; β-cyclodextrin inclusion with curcumin/carvacrol was supported by band shifts and DSC. Agar hydrogels dried into uniform xerogel films; agar–lignin remained stable, while agar–tannic acid failed. Methacrylated alginate and chitosan films exhibited improved handling and cohesion.

This study delineates a gel-to-xerogel route from marine biomass to functional films, combining sustainable extractions with chemical and supramolecular tailoring. Early films show structural integrity and processability; ongoing work targets water stability, thermo-mechanical optimization, and expansion to brown/green/microalgae, with a quantitative assessment of barrier, antioxidant/antimicrobial performance, biodegradability, and scale-up for food-packaging applications.

3.18. Synthesis of a Chitosan–Carrageenan-Based Bigel Using Aquatic Lipid as a Sustainable Liquid Phase for Fat-Reduced Chocolate

• Wahyu Ramadhan ^1,2,3, Aliyah Indira Sari ^1,3, Sugeng Heri Suseno ¹ and Fajar Domychen Sihombing ¹

¹ 

Department of Aquatic Products Technology, Faculty of Fisheries and Marine Sciences, IPB University, Bogor, Indonesia

² 

Center for Coastal and Marine Resources Studies, International Research Institute for Maritime, Ocean and Fisheries, IPB University, Bogor 16127, Indonesia

³ 

Aquatic Gels for Future Advanced Materials and Technologies Research Unit, IPB University, Bogor 16680, Indonesia

Fat reduction in chocolate confectionery can be achieved by partially replacing cocoa butter with structured systems such as bigels. Bigels are biphasic systems consisting of hydrogel and oleogel domains, which form interpenetrated networks to deliver both aqueous and lipid functionalities. In this study, a bigel system based on chitosan and kappa-carrageenan hydrogels incorporated into an oleogel matrix was synthesized and applied as a sustainable fat substitute in chocolate products. The oleogel was prepared using glycerol monostearate (GMS) as the structuring agent combined with pangasius oil, an aquatic lipid phase derived from a freshwater aquaculture by-product, characterized by low polyunsaturated fatty acid content and favorable sensory attributes. Compared to commercial plant-derived oils, this lipid source exhibited no detectable fishy odor, making it highly suitable for incorporation into sweet confectionery systems. Three ratios of hydrogel-forming agents (chitosan, a cationic polysaccharide: kappa-carrageenan, a sulfated polysaccharide = 25:75, 50:50, and 75:25) were evaluated in terms of oil binding capacity (OBC), thermal behavior, viscoelastic properties (frequency sweep), and proximate composition of the final chocolate formulation. The color, total fat content, and total energy were also assessed to determine the functional performance of the bigel system. Among all tested formulations, the 50:50 chitosan–kappa-carrageenan ratio exhibited the highest oil binding capacity (98.75%) and stable thermal characteristics, as indicated by a melting point shift on the thermogram, suggesting strong internal structuring and oil entrapment. The incorporation of this bigel (containing chitosan and GMS-structured oleogel) into the chocolate matrix resulted in a significant reduction in total fat content compared to commercial chocolate, while maintaining acceptable physical properties. These findings demonstrate the potential of sustainable hydrogel-in-oleogel systems structured with GMS and pangasius oil as functional fat replacers in chocolate products. Furthermore, the valorization of aquatic by-products such as pangasius oil offers a promising strategy to enhance the sustainability and nutritional profile of confectionery formulations.

3.19. Ultrasound-Enhanced Gelation and Functional Properties of Faba Bean Protein for Clean-Label Food Applications

• Gulcin Yildiz
• Department of Food Engineering, Igdir University, Iğdır 76000, Turkey

Faba bean (Vicia faba L.) protein has gained significant attention as a sustainable, allergen-friendly alternative in plant-based food formulations. However, its native gelling and techno-functional properties often require improvement to meet product development needs. This study investigates the effect of ultrasound treatment on the gelation behavior and functional attributes of faba bean protein isolate to enhance its performance in clean-label food systems. Given the increasing consumer demand for natural and minimally processed ingredients, ultrasound offers a non-thermal, environmentally friendly approach to protein modification that preserves nutritional quality.

Moderate-frequency ultrasound (40 kHz) was applied under controlled conditions to modify protein structure and interactions. Treated samples demonstrated improved solubility, reduced particle size, and enhanced surface activity. These modifications translated into significantly increased water-holding capacity, emulsifying ability, and gel strength. Rheological analysis revealed stronger, more elastic gel networks, while FTIR spectroscopy confirmed ultrasound-induced conformational changes, such as increased β-sheet content and partial unfolding—favorable for gel matrix formation.

The results suggest that ultrasound is a promising green processing method to enhance the functionality of faba bean protein without the need for chemical additives. This technique enables the development of structured, high-protein plant-based foods, including meat analogs, dairy alternatives, and nutritionally enriched gels. This study contributes to sustainable innovation in functional food design, aligning with consumer demand for minimally processed, protein-rich products.

3.20. Utilization of Dry-Fractionated Pea Starch as a Gelling Agent in Jelly Candies

• Davide De Angelis, Vittoria Latrofa, Giacomo Squeo, Francesco Caponio and Antonella Pasqualone
• Department of Soil, Plant and Food Science, University of Bari Aldo Moro, Via Amendola 165/a, 70126 Bari, Italy

Dry fractionation is primarily known as a technology for extracting plant proteins. However, this process also produces a considerable amount of starch-rich fraction, which is currently neglected and mainly destined for animal feed. In this study, we investigated the gelling and physicochemical properties of dry-fractionated (DF) pea starch and compared them to gelatin and corn starch. Jelly candies were produced with these gelling agents, and a rheological characterization was performed. Amylose and amylopectin, water absorption (WAIs) and solubility indexes (WSIs), and the Least Gelling Concentration (LGC) were determined by the ingredients. Jelly candy formulations were based on the LGC results. Starch concentrations increased by 4% increments, as smaller increases showed no significant rheological differences. Rheological characterization included amplitude sweep tests to define the linear viscoelastic region (LVR); yield stress and strain at the LVR limit were used to construct a texture map. Frequency sweep and shear rate ramp tests were also performed. DF pea starch showed a higher amylose content and WSI than corn starch (39.7% vs. 15.5%). The LGC values were 16% for DF pea starch, 12% for corn starch, and 6% for gelatin. DF pea starch jelly candies showed higher viscosity and more resistance to shear stress than corn starch ones, due to their higher amylose content. However, DF pea starch gels had poorer structural recovery, suggesting lower flexibility and elasticity under deformation. Corn starch gels recovered better and were more elastic. Rheological texture map indicated that DF pea starch candies were mushy, corn starch ones were rubbery, and gelatin-based candies were tough. Rheological analysis showed that DF pea starch forms a weaker gel, but blending it with corn starch may help replicate gelatin texture. As a co-product of protein extraction and often underutilized, DF starch offers a sustainable opportunity for new product development.

4. Session 4: Gels in Medicine, Regenerative Medicine, Pharmacy, and Personal Care Products

4.1. A Cytocompatible Photoresponsive Hydrogel to Study Cell Response to Dynamic Topographies

• Maaike Bril ^1,2, Albert Schenning ^2,3 and Nicholas A. Kurniawan ^1,2

¹ 

Department of Biomedical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands

² 

Institute for Complex Molecular Systems, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands

³ 

Department of Chemistry and Chemical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands

Introduction: In tissues, cells need to continually interact with topographically changing extracellular environments. However, most studies on cellular responses to topographical cues have focused on static conditions, neglecting the dynamic, spatiotemporal variations found in native tissues. To address this gap, we introduce a simple and effective approach: a dynamic cell culture platform utilizing a light-responsive spiropyran-containing poly(N-isopropylacrylamide) (Sp-pNIPAM) hydrogel.

Methods: We produced surface-constrained Sp-pNIPAM hydrogels coated with a thin elastomeric layer to minimize buffer interference. Upon blue light illumination (455 nm) through a mask, the stable, hydrophilic protonated merocyanine form in the exposed areas isomerizes to the hydrophobic spiropyran form, resulting in local hydrogel shrinkage and a controlled microscale change in hydrogel surface topography.

Results: Optical interferometry showed that a variety of topographies, defined by the mask features, can be successively and reversibly generated in the same hydrogel samples within ~15 min, without any measurable change in surface strain, stiffness, and roughness. When cells were cultured on the hydrogels, no significant difference in cell viability and DNA damage was observed before or after (masked) illumination. Recurring light-induced topographical changes were observed to result in reorganization of cell nuclei and focal adhesions, where fibroblasts form their focal adhesions (FAs) largely on the dynamic regions but shift their nuclei away from the dynamic regions. This dynamic conditioning was further found to be associated with epigenetic modifications and modulation of fibroblast phenotypes.

Conclusions: Overall, our hydrogel-based platform offers a new approach to dissect the dynamic interplay between cells and their microenvironment and shines a new light on the cell’s ability to adapt to topographical changes through FA-based mechanotransduction.

4.2. Advancing Nanomaterial Immunomodulation with Engineered ECM-Mimicking Matrices

• Mariannna Roca ¹, Naym Blal ¹, Zeynep Renkler ², Antonia Di Mola ¹, Ilaria De Martino ³, Velia Siciliano ³, Antonio Massa ¹, Vincenzo Guarino ² and Daniela Guarnieri ¹

¹ 

Department of Chemistry and Biology, “Adolfo Zambelli”, University of Salerno, Via Giovanni Paolo II 132, 84084 Salerno, Italy

² 

Institute of Polymers, Composites and Biomaterials, National Research Council of Italy, Mostra d’Oltremare Pad. 20, V.le J. F. Kennedy 54, 80125 Naples, Italy

³ 

Synthetic and Systems Biology for Biomedicine Lab, Istituto Italiano di Tecnologia, Naples, Italy

The extracellular matrix (ECM) plays a pivotal role in regulating immune cell behavior and modulating the biological response to nanomaterials (NMs). Understanding how immune cells interact with nanomaterials (NMs) in physiologically relevant environments is critical for the rational design of safe and effective biomedical applications. While conventional in vitro models typically expose cells to NMs in suspension, in vivo these materials frequently interact with ECM components, altering both matrix properties and cellular uptake mechanisms. This critical ECM–NM interface is often overlooked in nanosafety assessments and nanomedicine design. In this study, supported by the PRIN 2022 PNRR program, we developed ECM-mimetic like matrices to investigate the microenvironmental influence on macrophage responses to polystyrene nanoparticles (NPs). The synthetic substrates were engineered via electrospinning using biocompatible polymers blended with gelatin and hyaluronic acid (HA)—two key ECM components commonly found in hydrogels and biomedical gels. These matrices recapitulate essential structural and biochemical features of native ECM. These matrices were pre-loaded with polystyrene nanoparticles (NPs) and used to study the response of THP-1-derived macrophage-like cells. The results showed efficient cell adhesion to all matrix types, particularly gelatin-rich ones, with no significant cytotoxicity up to 48 h. Importantly, gelatin-containing matrices adsorbed significantly more NPs compared to controls, influencing NP availability and cell interaction. Fluorescence microscopy and flow cytometry confirmed NP internalization by macrophages in contact with the substrates. Notably, in this ECM-like configuration, cell viability was affected by the presence of NPs. Furthermore, we investigated the macrophage polarization in pro- or anti-inflammatory phenotypes through flow cytometry analysis. Our findings underscore the importance of using engineered ECM-inspired systems to better replicate the in vivo microenvironment in nanotoxicology and immunoengineering studies. Understanding how ECM properties affect NM bioavailability and immune cell behavior is crucial for advancing research in nanotoxicology, immunomodulation, and the development of next-generation therapeutic systems.

4.3. Amphiphilic pH-Responsive Core–Shell Nanoparticles Can Increase the Performances of Cellulose-Based Drug Delivery Systems

• Giuseppe Nunziata and Filippo Rossi
• Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”, Technical University of Milan, 20131 Milan, Italy

Abstract

Organic nanoparticles (NPs) and hydrogels have been widely studied in the biomedical field as drug delivery systems. Recently, the ability of the polymer network and NPs to physically interact with each other was applied to create a stable nanocomposite system with improved mechanical properties, one that was able to be injected inside the disease area and release the drug locally [1,2]. In this work, a drug delivery system based on the combination of pH-responsive poly((lactic acid-co-methacrylic acid)-b-(di(ethylene glycol) methyl ether methacrylate)) poly((PLA-co-MAA)-b-(EG₂MA)) nanoparticles with a cellulose-based solution was developed to create an injectable pH-responsive system for local drug delivery applications. Different types of drugs could be released at different pH conditions, both from the polymer network and NPs, to respond to future demands of using different drugs and therapeutic molecules at the same time for specific therapeutic treatments [3].

• References

• Bovone, G.; Guzzi, E.A.; Bernhard, S.; Weber, T.; Dranseikiene, D.; Tibbitt, M.W. Supramolecular Reinforcement of Polymer–Nanoparticle Hydrogels for Modular Materials Design. Adv. Mater. 2022, 34, 9.
• Appel, E.A.; Tibbitt, M.W.; Webber, M.J.; Mattix, B.A.; Veiseh, O.; Langer, R. Self-assembled hydrogels utilizing polymer–nanoparticle interactions. Nat. Commun. 2015, 6, 6295.
• Janjigian, Y.Y.; Shitara, K.; Moehler, M.; et al. Nivolumab plus chemotherapy versus chemotherapy as first-line treatment for advanced gastric cancer/gastroesophageal junction cancer/oesophageal adenocarcinoma (CheckMate 649): a multicentre, randomised, open-label, phase 3 trial. Lancet 2021, 398, 27.

4.4. Antibacterial Superabsorbent Hydrogels Based on Polysaccharides Crosslinked with Citric Acid

• Arina Vladislavovna Korotkova ¹, Ekaterina Sergeevna Chikanova ², Kristina Yurievna Kotyakova ², Yulia Alekseevna Makarets ² and Dmitry Vladimirovich Shtansky ²

¹ 

National University of Science and Technology “MISIS”, Moscow 119049, Russia

² 

Research Centre “Inorganic Nanomaterials”, National University of Science and Technology “MISIS”, Moscow 119049, Russia

Introduction: Functional hydrogels are currently being actively studied. Due to their unique set of properties, hydrogels are used in various fields. In particular, they are used for wound dressings, the global marker of which amounted to USD 476 million in 2024. These materials effectively absorb exudate from the wound and keep it moist. The use of polysaccharides ensures the required level of biocompatibility, crosslinking improves mechanical characteristics, and various additives impact certain properties.

Methods: Hydrogels were made from carboxymethylcellulose (CMC, 1000 kDa) and hyaluronic acid (HA, 800 kDa) crosslinked by citric acid (CA). Polycaprolactone (PCL) nanomates obtained by electrospinning, CuO and ZnO nanoparticles, and aloe vera (AV) were added to hydrogels. The samples were examined by FTIR, SEM and EDS analysis systems. Their appearance, swelling ratio, dissolution in tris-buffer and isotonic solution, pH, and hydrophilic, adhesive, mechanical, and antibacterial properties were studied.

Results: The resulting transparent materials have high adhesive and hydrophilic properties. They have an interconnected system of pores with a size of 5–100 microns. Based on the FTIR results, the crosslinking of -OH groups in polysaccharides using CA was confirmed by the determination of C=O, C-O, O-C-O, and C-O-C ester vibrations. The relative elongation of materials is 170%. Young’s modulus is 0.8 kPa. The highest swelling ratio was observed for samples with ZnO, CuO, and AV and measured as 919, 749 and 792%, respectively. The hydrogels were stable for 7 days in model solutions. The highest rate of dissolution was observed in isotonic solution. The materials showed antibacterial properties against Gram-positive and Gram-negative bacteria.

Conclusions: The materials obtained showed antipathogenic, high mechanical, absorption, and stability properties. It makes them suitable for making wound dressings and effective wound regeneration.

The work was carried out with the financial support of the Russian Science Foundation (Agreement No. 25-19-00458).

4.5. Bioactive Hydrogel Enriched with Natural-Origin Components Has Benefits for Therapeutic Applications

• Mariana Chelu, Monica Popa, Gabriela Marinescu, José María Calderón Moreno
• “Ilie Murgulescu” Institute of Physical Chemistry, 202 Spl. Independentei, 060021 Bucharest, Romania

Natural products have consistently attracted scientific interest as promising sources for the development of new and effective therapies due to their potential benefits and relatively low risk of adverse effects. Royal Jelly is a natural product with exceptional biological characteristics, a broad apitherapeutic spectrum and great demand in the pharmaceutical and food industries due to its nutritional properties. It has been shown to inhibit a wide range of bacterial strains, making it a promising candidate for combating microbial infections. Aloe vera is known for its benefits for the skin, acting as a moisturizer and healer for conditions like burns and acne; meanwhile, Royal Jelly offers anti-inflammatory, antioxidant and anti-aging effects due to its rich nutrient profile, although studies are ongoing to fully establish its therapeutic potential. The combined use of Aloe vera and Royal Jelly holds potential for enhancing the body’s defense mechanisms against cellular stress, although more research is needed.

The current research objective is related to the synthesis, analysis and characterization of the physicochemical and pharmaceutical properties of the mixture of Royal Jelly and Aloe vera to form a biocomposite hydrogel of natural origin for use in therapeutic and anti-aging applications. The prepared hydrogel was comprehensively analyzed and exhibited organoleptic features and favorable properties for wound dressing applications in terms of its morpho-structural characteristics, swelling, pH and spreadability. The materials were analyzed by Fourier transform infrared (FT-IR) and Raman spectroscopy, while morphological analysis was performed by scanning electron microscopy (SEM).

The results highlight the considerable potential of these natural hydrogels for the management of chronic wound treatments and microbial infections and draw attention to the advantageous incorporation of Royal Jelly-derived bioactive compounds, providing multiple benefits such as anti-aging, anti-inflammatory and antibacterial properties, while promoting rapid wound healing.

4.6. Bioactive Sol–Gel Coatings Obtained by Network Embedding of Phytosynthesized Selenium Nanoparticles

• Monica Raduly, Valentin Raditoiu, Alina Raditoiu, Adriana Frone and Iuliana Raut
• National Institute for Research & Development in Chemistry and Petrochemistry—ICECHIM, 202 Splaiul Independentei, 060021 Bucharest, Romania

Nanotechnology plays a crucial role in the advancement of functional materials, particularly in biomedical, food, and surface protection applications. Among the metallic nanoparticles investigated, selenium nanoparticles (SeNPs) are notable due to their antioxidant, antibacterial, and anticancer activities. Phytosynthesis offers an environmentally friendly and cost-effective approach to obtain SeNPs, employing plant extracts as both reducing and stabilizing agents. However, their efficient use requires stabilization and controlled release, for which encapsulation in sol–gel matrices has proven to be a versatile and effective strategy [1,2,3].

This work presents the synthesis and characterization of bioactive sol-gel coatings functionalized with selenium nanoparticles (SeNPs) obtained via phytosynthesis. SeNPs were generated using Trifolium pretense or Curcuma longa plant extracts, which act as reducing and stabilizing agents, converting Se⁴⁺ ions from Na₂SeO₃ into elemental selenium (Se⁰). The nanoparticles were incorporated into hybrid sol–gel matrices generated from tetraethyl orthosilicate (TEOS) and dimethoxydimethylsilane (DMDMS) in various ratios (TEOS:DMDMS = 2:0.5–2, v/v). The hydrolysis and condensation of the precursors were catalyzed by 0.1 M HNO₃ at 25 °C for 24 h.

The resulting sols were deposited onto glass substrates by dip-coating and thermally treated to consolidate the network and immobilize the SeNPs. Surface morphology was investigated by atomic force microscopy (AFM) and scanning electron microscopy (SEM), chemical structure by Fourier-transform infrared (FTIR) spectroscopy, and optical properties by UV-Vis. Antimicrobial tests against S. aureus, E. coli, and C. albicans confirmed the biological activity of the coatings.

The results suggest strong potential for these SeNP-based sol–gel materials in biomedical and protective applications such as wound dressings, antioxidant/UV protection films, and antibacterial textiles.

4.7. Boosting Engineered Cartilage Formation with Recombinant Spider Silk

• Hongji Zhang, Fengjie Zhang and Chao Wan

¹ 

Center for Neuromusculoskeletal Restorative Medicine, Hong Kong Science Park, Hong Kong SAR, China

² 

Key Laboratory of Regenerative Medicine, Ministry of Education (Shenzhen Base), School of Biomedical Sciences Core Laboratory, Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China

Introduction: Articular cartilage, being avascular and aneural and lacking lymphatic drainage, exhibits minimal intrinsic capacity for self-repair. The development of effective therapies for cartilage regeneration therefore remains an unmet clinical need. A critical step toward functional cartilage tissue engineering is the design of biomaterials that promote chondrocyte adhesion, proliferation and differentiation. In this study, we examined a novel protein-based silk material for its ability to modulate chondrocyte behavior and support engineered cartilage formation both in vitro and in vivo.

Methods: Primary chondrocytes were isolated from neonatal mice and cultured in chondrogenic medium. In vitro, chondrocytes were co-cultured with a type of recombinant spider silk. Extracellular matrix (ECM) proteoglycan deposition was assessed by Alcian blue staining, while protein expression was evaluated by Western blot. Total RNA was extracted from micromass cultures, and chondrogenic markers (Sox9, Col2α1, and aggrecan) were quantified using real-time PCR. For in vivo studies, chondrocyte-laden silk bioscaffolds were implanted subcutaneously into SCID mice for 3 and 6 weeks. Engineered cartilage formation was analyzed histologically using Alcian blue and Safranin O staining.

Results: The protein-based silk material created a favorable 3D microenvironment that promoted strong chondrocyte adhesion and enhanced chondrogenic differentiation. In vitro, chondrocytes maintained high viability on the silk material, with conditioned cultures showing elevated cartilage-specific glycosaminoglycan accumulation and the upregulated expression of chondrogenic genes. A high cell density was observed at the material interface, indicating robust cell–material interactions. In vivo, silk-based chondrocyte bioscaffolds supported cartilage tissue formation after implantation in SCID mice, as confirmed by histological analysis.

Conclusion: The synthetic protein-based silk material exhibits excellent biocompatibility, non-toxicity, controlled biodegradability and strong chondrogenesis-supportive properties. These findings highlight its potential as a promising scaffold for engineered cartilage tissue and as a candidate for future cartilage repair and regeneration therapies.

4.8. Design of Alginate/Gelatin Hydrogels for Craniofacial Bone Tissue Engineering: Optimizing Osteogenesis in Dental Pulp Stem Cells Without Compromising Other Cellular Functions

• Zied Ferjaoui ¹, Roberto López-Muñoz ¹, Soheil Akbari ², Diego Mantovani ¹ and Roberto D. Fanganiello ¹

¹ 

Faculty of Science and Engineering, Laval University, Quebec City, QC G1V 0A6, Canada

² 

Department of Chemical Engineering, Laval University, Quebec City, QC G1V 0A6, Canada

Alginate/gelatin (Alg-Gel) hydrogels have been explored in combination with mesenchymal stromal/stem cells (MSCs) to support bone tissue formation, reconstruction, and regeneration. A key challenge for clinical translation is optimizing the stiffness of Alg-Gel hydrogels to selectively enhance osteogenesis without interfering with other vital cellular functions. In this study, we investigated the influence of hydrogel stiffness on the adhesion, morphology, proliferation, and osteogenic differentiation of dental pulp stem cells (DPSCs), identifying optimal formulations to decouple osteogenic cues from other cell behaviors. A range of Alg-Gel combinations was cast and cross-linked with 2% CaCl₂ to finetune the mechanical properties. Two formulations were selected: a “low-stiffness hydrogel” (2% alginate, 8% gelatin; 11 ± 1 kPa) and a “high-stiffness hydrogel” (8% alginate, 12% gelatin; 55 ± 3 kPa). The hydrogels exhibited distinct swelling and degradation profiles, with the stiffer formulation showing reduced degradation and improved mechanical stability. Both supported robust DPSC adhesion and proliferation over extended culture periods. However, osteogenic differentiation, assessed by alkaline phosphatase activity, Alizarin Red staining, and bone nodule formation, was significantly enhanced in the high-stiffness hydrogel. These findings demonstrate that the stiffness of Alg-Gel hydrogels can be fine-tuned to promote osteogenesis without compromising other essential cellular functions. Importantly, this biomaterial is currently being investigated as a promising scaffold for craniofacial bone tissue engineering applications.

4.9. Development of Chitosan–Pectin Hydrogels for Controlled Drug Release

• Ana Isabel Ribeiro ¹, Andreia Romeiro ², Patrícia Alves ^1,2 and Mariana Emilia Ghica ¹

¹ 

Department of Chemical Engineering, CERES, University of Coimbra, 3030-790 Coimbra, Portugal

² 

Department of Chemical Engineering, CEMMPRE, ARISE, University of Coimbra, Rua Silvio Lima-Polo II, 3030-790 Coimbra, Portugal

Hydrogels are promising materials for smart drug delivery systems due to their biocompatibility, high water absorption capacity, and structural similarity to biological tissues, mainly enabling controlled and localized drug release. In this work, chitosan–pectin composite hydrogels were developed through physical crosslinking at different ratios (1:1, 2:1, and 1:2) and pectin concentrations (1%, 2.5%, and 5% w/v), incorporating the drug sulfasalazine. The hydrogels were characterized in terms of their structure, porosity, swelling capacity, and mass loss. In addition, the hydrogels were analyzed using Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). FTIR analysis confirmed the formation of the polyelectrolyte complex and efficient sulfasalazine incorporation, as evidenced by the presence of bands characteristic of the functional groups of both polymers and of the drug’s bonds. SEM revealed a transition from porous to compact structures as the pectin concentration increased. Hydrogels with higher chitosan contents exhibited greater porosity and swelling capacity, which is consistent with the SEM observations. In general, it was observed that the influence of pectin on porosity depends on the molar ratio of the polymers. In vitro sulfasalazine release studies fitted both the Higuchi and zero-order models, suggesting that drug release is controlled by diffusion and polymer matrix relaxation. These results demonstrated the potential of chitosan–pectin hydrogels as effective vehicles for controlled drug delivery applications.

4.10. Development of Novel Chitosan–Gelatine-Based Hydrogels for Drug Delivery Applications

• Sara Beatriz Cardoso ¹, Patrícia Alves ^1,2, Andreia Romeiro ³ and Mariana Emilia Ghica ¹

¹ 

Department of Chemical Engineering, CERES, University of Coimbra, 3030-790 Coimbra, Portugal

² 

Department of Mechanical Engineering, CEMMPRE, ARISE, University of Coimbra, Rua Silvio Lima–Polo II, 3030-790 Coimbra, Portugal

³ 

Department of Chemical Engineering, CEMMPRE, ARISE, University of Coimbra, Rua Silvio Lima–Polo II, 3030-790 Coimbra, Portugal

Due to the unique properties of chitosan, a biodegradable natural polymer, it has been introduced as a substitute for various materials used in a wide array of applications, from packaging, tissue engineering to wound dressings and controlled release of drugs [1]. For certain applications, however, chitosan hydrogels may not have the best physicochemical characteristics, or there is an interest in making the hydrogel more responsive to certain environmental characteristics like pH. Hence, the use of reticulate agents and blending other materials became a useful strategy. Gelatine can form a polyelectrolyte complex with chitosan due to the electrostatic interactions between chitosan’s amino groups and gelatine’s carboxyl groups aiding in the gelation process [2]. Meanwhile, glyoxal helps stabilise the hydrogel’s structure, increasing its mechanical strength [3].

In this work, we incorporated gelatine and glyoxal with chitosan to synthetize a hydrogel for the delivery of paracetamol which was then freeze-dried. The samples were then analysed using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and swelling, degradation and drug release tests were also performed. Several combinations of chitosan and gelatine were used to find a good balance between porosity, durability and release ability. The systems with best performance were those containing the same gelatine and chitosan concentration (2.5%, w/v) mixed in two different ratios 1:1 and 1:2.

Acknowledgements

This work was developed under the project 3DBIOGEL4HEALTH – “Exploring the 3D BioPrinting for Design of Novel Biodegradable Hydrogels as Lutein Carriers”, funded by national funds by the Foundation for Science and Technology (FCT) - Ref.ª 2023.12614.PEX

• Reference

• Yarahmadi, A.; Dousti, B.; Karami-Khorramabadi, M.; Afkhami, H. Materials based on biodegradable polymers chitosan/gelatin: a review of potential applications. Front. Bioeng. Biotechnol. 2024, 12, 1397668. https://doi.org/10.3389/fbioe.2024.1397668.
• Mathew, S.A.; Arumainathan, S. Crosslinked Chitosan–Gelatin Biocompatible Nanocomposite as a Neuro Drug Carrier. ACS Omega 2022, 7, 18732–18744. https://doi.org/10.1021/acsomega.2c01443.
• Tsai, C.-C.; Young, T.-H.; Chen, G.-S.; Cheng, N.-C. Developing a Glyoxal-Crosslinked Chitosan/Gelatin Hydrogel for Sustained Release of Human Platelet Lysate to Promote Tissue Regeneration. Int. J. Mol. Sci. 2021, 22, 6451. https://doi.org/10.3390/ijms22126451.

4.11. Engineered HPMC/Starch Hydrogels for pH-Independent Drug Release

• David Rohindra, Tejesvi Patel and Roselyn Lata
• Department of Biological and Chemical Science, The University of the South Pacific, Suva 0000, Fiji

Introduction:

Natural polymer-based hydrogels offer a biodegradable and biocompatible platform for sustained drug release, especially for drugs with pH-dependent solubility. This study investigates the development of hydrogel films using hydroxypropyl methylcellulose (HPMC) and taro starches from two cultivars—Uroni Vonu (high amylopectin) and Vavai Dina (high amylose)—for the delivery of quetiapine fumarate, a weakly basic drug. The aim was to develop a matrix capable of achieving pH-independent, sustained drug release.

Methods:

Gelatinized taro starch was blended with HPMC at 80:20 and 60:40 (HPMC/Starch) ratios. Succinic acid was incorporated as both a crosslinker and acidifier. Films were characterized using FTIR, SEM, DSC, and rheological methods. Swelling and drug release behavior were assessed in gastric (pH 1.2) and intestinal (pH 6.8) fluids. Release kinetics were evaluated using Zero-order, First-order, Higuchi, Hixson–Crowell, and Korsmeyer–Peppas models.

Results:

FTIR and SEM confirmed crosslinking and improved matrix porosity, especially in 60:40 blends. All hydrogels showed pH-independent swelling, with slightly greater uptake in amylopectin-rich formulations. Drug release from uncrosslinked films was pH-dependent. The release of quetiapine fumarate in both gastric fluid and succinic acid-crosslinked hydrogels followed the Korsmeyer–Peppas model, likely due to the presence of acidic conditions. In the crosslinked formulations, succinic acid generates an internal acidic microenvironment that mimics the gastric pH, supporting a diffusion-driven release mechanism. In contrast, the pure HPMC and non-crosslinked hydrogel films best fit the Hixson–Crowell model in intestinal fluid, suggesting erosion-based release from shrinking geometries.

Conclusion:

Succinic acid-crosslinked HPMC/taro starch hydrogels offer a promising platform for pH-independent delivery of quetiapine fumarate. Release kinetics in both gastric fluid and crosslinked films followed the Korsmeyer–Peppas model due to acidic environments—externally in the medium and internally via succinic acid’s microenvironment. In contrast, uncrosslinked formulations followed Hixson–Crowell kinetics.

4.12. Exploring the Potential of Self-Healing Hydrogels for Breast Cancer Management

• Preeti Kush ¹, Dr. Parveen Kumar ² and Dr. Ranjit Singh ¹

¹ 

Adarsh Vijendra Institute of Pharmaceutical Sciences, Shobhit University, Gangoh, Saharnpur 247341, UP, India

² 

Exigo Recycling Pvt Ltd., Karnal, Haryana 132103, India

Introduction: Globally, breast cancer (BC) is the most common cancer among women (~30% of all new cancer cases annually) and will be the second leading cause of death among women (~42,170) in the United States, 2025 (https://www.breastcancer.org/facts-statistics). It is conventionally treated by surgery, radio-, hormone-, chemo-, and targeted therapies, and its treatment depends upon its subtype, stage, and degree of metastasis. Self-healing hydrogels (SHHs) are an innovative approach for the management of BC owing to their distinct properties like self-healability, shear-thinning property, injectability, and stimuli responsiveness, and can be used as a multimodal platform for synergistic cancer therapy.

Methods: The literature (research and review articles) was retrieved from various search engines like Google Scholar, Scopus, Science Direct, and PubMed, using keywords such as self-healing hydrogels, breast cancer, and chemotherapy, from 2013 to Feb 2025. Results: SHHs are used as a multimodal platform for managing BC using diverse approaches like stimuli-responsive release of chemotherapeutics, co-delivery of drugs, phototherapy, chemodynamic therapy, starvation therapy, and sonodynamic therapies or combination therapies. Moreover, these hydrogels are durable, reusable, and fatigue-resistant and can restore their structural integrity even after multiple destructions within a few seconds/hours. Additionally, SHHs can also adjust their pore structure because of persistent break-healing cycles, leading to higher encapsulation of chemotherapeutics with uniform distribution.

Conclusion: Owing to their distinct properties, SHHs can be used as a promising carrier for the delivery of chemotherapeutics with synergistic anticancer activity on BC cells, even at minimal adverse effects, either alone or in combination with other novel strategies.

4.13. Formulation and In Vitro Evaluation of a Thermosensitive Hydrogel as an Intravaginal Drug Delivery System

• Gladys Arline Politrón Zepeda ¹, Moisés Martínez Velázquez ¹, Rogelio Rodríguez Rodríguez ² and Zaira Yunuen García Carvajal ¹

¹ 

Department of Pharmaceutical Medical Biotechnology, Center for Research and Assistance in Technology and Design of the State of Jalisco (CIATEJ), A.C., Guadalajara 44270, Mexico

² 

Department of Health Sciences, University Center of the Valles (CUValles), University of Guadalajara Ameca, Jalisco 46600, Mexico

Introduction.

Cervical cancer remains one of the leading causes of female mortality worldwide. Localized drug delivery systems, such as thermosensitive hydrogels for intravaginal administration, offer the potential to improve therapeutic efficacy while minimizing systemic side effects. This study aimed to formulate a thermosensitive hydrogel based on Pluronic F127, hydroxypropyl methylcellulose (HPMC), and Carbopol 940, and to evaluate its physicochemical properties and the cytotoxicity of ibuprofen and cisplatin to explore a potential additive effect.

Methods.

A thermosensitive hydrogel was prepared using the cold method with Poloxamer 407, hydroxypropyl methylcellulose (HPMC), and Carbopol 940. Component ratios were optimized through mixture design considering gelling temperature and viscosity. Physicochemical characterization included viscosity (rotational viscometer), sol–gel transition temperature (tube inversion), and swelling ratio in simulated vaginal fluid. Drug entrapment was assessed by UV-Vis spectrophotometry. Cytotoxicity was assessed in HeLa cells using the MTT assay after exposure to ibuprofen and cisplatin for 24–72 h.

Results.

The hydrogel exhibited a swelling ratio (SR) of 2.08 after 3 h of hydration, corresponding to the point of maximum absorption. Cytotoxicity assays showed that ibuprofen alone induced a dose-dependent decrease in HeLa cell viability, from 98.9% at 0.39 mM to 15.6% at 12.5 mM. The calculated IC₅₀ was 9.8 mM. In contrast, sequential treatment with cisplatin at its IC₅₀ concentration (24 h) followed by ibuprofen (24 h) markedly enhanced the cytotoxic effect. Under these conditions, viability was already reduced to 44.8% at 0.39 mM and further declined to 9.3% at 12.5 mM, indicating an additive effect of the combined therapy compared with ibuprofen alone.

Conclusions.

A sterile thermosensitive hydrogel was successfully formulated and characterized. The combination of ibuprofen and cisplatin reduced HeLa cell viability more than individual treatments, indicating a potential additive effect, although further studies are required to confirm this.

Acknowledgment.

This study was supported by project CBF2023-2024-2164.

4.14. Gels Based on Natural Polymers Containing Silver Nanoprisms for Combined Chemo/Phototherapy of Cancer

• Eva Sousa Marta ¹, Sérgio R. S. Veloso ^1,2, Goreti Pereira ³ and Elisabete M. S. Castanheira ¹

¹ 

Physics Centre of Minho and Porto Universities (CF-UM-UP), University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal

² 

CINBIO, Universidad de Vigo, 36310 Vigo, Spain

³ 

CESAM and Department of Chemistry, University of Aveiro, 3830 Aveiro, Portugal

Cancer therapy remains a major contemporary challenge due to the complexity and heterogeneity of tumour biology. In recent years, nanotechnology has emerged as a promising approach in both cancer diagnosis and treatment with the development of multifunctional nanosystems capable of targeted delivery and therapeutic responsiveness [1,2,3]. In this regard, hydrogels have been extensively studied as drug delivery systems for cancer, due to their biocompability, physicochemical tailorability, ability to protect therapeutic agents and the spatiotemporal control of their release [4]. The combination of liposomes containing plasmonic nanoparticles with polymeric matrices represents a particularly attractive strategy for enhancing drug delivery performance, offering the potential to minimise burst release and improve tissue localisation, as well as the capability of response to external stimuli [5]. These plasmonic lipogels allow multiple functionalities, including photothermia and controlled drug delivery, contributing to a multimodal therapeutic approach [6].

In this work, chitosan-based hydrogels and lipogels containing novel silver nanoprisms were developed and studied as multifunctional therapeutic agents, combining local chemotherapy and photothermia. The hybrid nanosystems were characterized and tested as nanocarriers for an anticancer drug, 5-fluorouracil. The results obtained are promising for the application of the new lipogels in multimodal cancer therapy, enabling the controlled release of antitumor drugs triggered by NIR laser light.

• Reference

• Zhang, X.-F.; Liu, Z.-G.; Shen, W.; Gurunathan, S. Silver Nanoparticles: Synthesis, Characterization, Properties, Applications, and Therapeutic Approaches. Int. J. Mol. Sci. 2016, 17, 1534. https://doi.org/10.3390/ijms17091534.
• Yetisgin, A.A.; Cetinel, S.; Zuvin, M.; Kosar, A.; Kutlu, O. Therapeutic Nanoparticles and Their Targeted Delivery Applications. Molecules 2020, 25, 2193. https://doi.org/10.3390/molecules25092193.
• Bhowmik, A.; Bandyopadhyay, A.; Chattopadhyay, A. Cytotoxic and mutagenic effects of green silver nanoparticles in cancer and normal cells: a brief review. Nucleus 2019, 62, 277–285. https://doi.org/10.1007/s13237-019-00293-0.
• Mortier, C.; Costa, D.C.S.; Oliveira, M.B.; Haugen, H.J.; Lyngstadaas, S.P.; Blaker, J.J.; Mano, J.F. Advanced hydrogels based on natural macromolecules: chemical routes to achieve mechanical versatility. Mater. Today Chem. 2022, 26, 101222. https://doi.org/10.1016/j.mtchem.2022.101222.
• Li, Y.; Cong, H.; Wang, S.; Yu, B.; Shen, Y. Liposomes modified with bio-substances for cancer treatment. Biomater. Sci. 2020, 23, 6442–6468. https://doi.org/10.1039/D0BM01531H.
• Gomes, V.; Veloso, S.R.S.; Correa-Duarte, M.A.; Ferreira, P.M.T.; Castanheira, E.M.S. Tuning Peptide-Based Hydrogels: Co-Assembly with Composites Driving the Highway to Technological Applications. Int. J. Mol. Sci. 2023, 24, 186. https://doi.org/10.3390/ijms24010186.

4.15. Harnessing Nature: Hydrogels Derived from Bacterial Cellulose and Chitosan for Biomedical Applications

• Joachim Emeka Arikibe ^1,2,3, Roselyn Lata ³ and David Rohindra ³

¹ 

Department of Chemical Sciences, University of Padova, Via F. Marzolo, 1, 35131 Padova, Italy

² 

Department of Drug Delivery Across Biological Barriers, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Campus E8 1, 66123 Saarbrücken, Germany

³ 

School of Agriculture, Geography, Environment, Oceans and Natural Sciences, The University of the South Pacific, Private Mail Bag, Suva, Fiji

Bacterial cellulose (BC) is a biopolymer with excellent mechanical strength and purity. However, its utilization in biomedical applications is hampered due to its limitations in reactive functional groups. This work presents the development of semi-interpenetrating hydrogels (semi-IPNs) by combining BC with chitosan (Ch) and crosslinking with genipin (Gp), using a straightforward two-step strategy. First, an in situ method was employed to incorporate chitosan directly into the BC matrix during the Gluconacetobacter xylinus fermentation process. This was followed by an ex situ crosslinking step, where BC-Ch was immersed in a genipin solution to enhance network stability and biocompatibility. The FTIR study revealed new amide I and II bands and C–N stretching vibrations, confirming the successful modification of BC with Ch. SEM analysis demonstrated that crosslinked BC-Ch-Gp hydrogels exhibited a compact, highly interconnected fibril network with improved porosity. Differential Scanning Calorimetry indicated the presence of free, bound, and intermediate water types, contributing to the good water retention capacity of the hydrogels. Swelling studies revealed pH-responsive behaviors, with higher swelling at low pH for crosslinked samples and an increased chitosan ratio further enhancing this response. Mechanical testing showed improved stiffness and reduced moisture content in crosslinked hydrogels, making them more suitable for biomedical environments. Antibacterial evaluation confirmed effective inhibition of Escherichia coli and Staphylococcus aureus. In vitro drug release studies using quetiapine fumarate showed sustained release profiles following the Higuchi model and a combination of non-Fickian and super case II transport, indicating controlled diffusion and matrix relaxation. Using non-pathogenic bacteria and coconut-derived media, this simple dual-method strategy produced safe and functional hydrogels suitable for applications in controlled drug delivery, wound healing, and advanced biomedical dressings.

4.16. Hyaluronic Acid-Based Hydrogels for Suprachoroidal Administration in Glaucoma Treatment: Influence of Precursor Characteristics on Hydrogel Properties

• Inês Anselmo Pereira, Ana Clotilde Fonseca and João Pedro Vareda
• Department of Chemical Engineering, Centre for Mechanical Engineering, Materials and Processes, ARISE, University of Coimbra, Rua Sílvio Lima- Pólo II, 3030-790 Coimbra, Portugal

Introduction: Glaucoma is a leading cause of vision loss that is associated with an increase in intraocular pressure. The injection of a hydrogel into the suprachoroidal space (SCS) is a promising treatment, decreasing intraocular pressure and allowing drug delivery.

Methods: We developed hydrogels based on hyaluronic acid (HA) and poly(ethylene glycol) (PEG) for the potential delivery of hydrophobic drugs in the SCS. First, HA was modified with thiol groups and then crosslinked with PEG acrylates via Michael addition, inducing gelation. To mimic physiological conditions, a PBS buffer was used as the solvent. Curcumin was encapsulated as a model hydrophobic drug. Westudied the influence of varying the modification degree of HA and PEG chain length on the final properties of the hydrogel.

Results: We obtained cohesive hydrogels with fast in situ gelation times, approximately two minutes, that are tough and able to withstand high shear strains. The gels have a distinctive intense color due to the dispersion of curcumin in the polymer matrix. In vitro tests revealed that hydrogels release the encapsulated curcumin over time, losing their color.

Conclusion: Weobtained hydrogels with interesting properties, compatible withinjection into the SCS. These materials are very promising and will continue to be studied for this application.

4.17. Injectable Thermoresponsive Hyaluronic Acid–GelMA Composite Hydrogel Loaded with Tacrolimus and Tyrosinase-Activating Peptides for Local Immunomodulation and Melanocyte Regeneration in Vitiligo

• Mthabisi Talent George Moyo
• Department of Medical Biochemistry, Faculty of Medicine, Girne American University, Karmi Campus, Kyrenia 99428, North Cyprus, Turkey

Vitiligo is an autoimmune skin disorder characterized by localized melanocyte loss due to immune-mediated destruction, resulting in depigmented lesions. Current therapies often lack targeted delivery and regenerative capacity. In this study, we developed a multifunctional injectable hydrogel system composed of methacrylated hyaluronic acid (HAMA) and gelatin methacrylate (GelMA), designed for localized immunomodulation and melanocyte regeneration. The composite hydrogel was synthesized via photoinitiated free-radical polymerization using lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP) as a cytocompatible photoinitiator under visible light (405 nm). This method enabled tunable crosslinking density, which was optimized for mechanical stiffness mimicking native dermis (~1–3 kPa). The hydrogel formulation incorporated tacrolimus encapsulated within biodegradable poly(lactic-co-glycolic acid) (PLGA) nanoparticles for sustained, pH-responsive release and synthetic tyrosinase-activating peptides to promote melanogenic signaling. Rheological analysis confirmed shear-thinning behavior and sol–gel transition at physiological temperature (37 °C). The hydrogel demonstrated excellent biocompatibility and functional efficacy in vitro, as shown by the 3D co-culture of primary human keratinocytes and melanocytes embedded within the hydrogel matrix, which exhibited enhanced melanogenesis through melanin quantification assays and upregulation of MITF and TYR gene expression. Immunomodulatory effects were validated by co-culture with activated CD8+ T-cells, which showed reduced cytotoxicity and altered cytokine release profiles. Hydrogel degradation kinetics and tacrolimus release profiles were characterized under simulated dermal pH (5.5) and physiological pH (7.4), confirming controlled biodegradability and sustained drug release. Overall, the injectable HAMA–GelMAhydrogel platform provided a dual-function localized immunosuppressive and regenerative microenvironment, offering a promising strategy for vitiligo treatment. These findings support further in vivo evaluation and potential clinical translation.

4.18. Microfluidic Fabrication of Graphene Oxide-Enriched Alginate Nanocomposite Hydrogels for Enhanced Porous Structure and Antibacterial Wound Dressings

• Burak Erayhan ¹, Duygu Anaklı ², Israfil Kucuk¹, Meltem Macit ³, Gülengül Dumanlı³, Onur Cem Namlı ⁴, Muhammad Hamza ⁵ and Muhammad Sohail Arshad ⁵

¹ 

Institute of Nanotechnology, Gebze Technical University, Kocaeli, Turkey

² 

Faculty of Engineering, Department of Chemical Engineering, Sivas Cumhuriyet University, Sivas, Turkey

³ 

Department of Pharmaceutical Technology, Faculty of Pharmacy, Yeditepe University, Istanbul, Turkey

⁴ 

Department of Mechanical Engineering, Faculty of Engineering, Yeditepe University, Istanbul, Turkey

⁵ 

Faculty of Pharmacy, Bahauddin Zakariya University, Multan, Pakistan

Wound healing aims to regenerate wounds with wound dressings such as hydrogels. An ideal wound dressing biomaterial has biocompatible, biodegradable, biomechanics, porous and anti-bacterial properties. The applicability of the general methods in wound healing material is simple, but their inadequacy given their antibacterial, porous and toxic properties can be eliminated using microfluidics. The hydrogel produced by reaction of microfluidic nanocomposite foams with a crosslinker can be used as wound dressing with more desirable antibacterial properties, a porous structure, and biocompatibility. Even though alginate polymer is a preferred biopolymer for hydrogel-based wound dressing production due to its biocompatible, biodegradable, and hydrophilic benefits, its strength and antibacterial properties remain weak. In this study, we aimed to characterize the production of nanocomposite hydrogels by enriching graphene oxide (GO), which has high biocompatibility, antibacterial, bioadhesion, thermal and mechanical abilities, to improve the mechanical, antibacterial and porous structure properties of alginate hydrogels, and to compare these results with alginate hydrogels by a traditional method. To achieve this, GO-enriched alginate hydrogels were produced both by the traditional method and microfluidics, and XRD, DSC, TGA-DTA, FTIR, SEM, tensile strength characterizations and antibacterial testing were performedf. According to these characterization results, it was observed that the GO enrichment improved the thermal, mechanic properties, and crystal structure properties of the alginate hydrogel. In addition, as a result of SEM results, it was observed that the microfluidic hydrogels had a more desirable porous structure. Additionally, according to the antibacterial test results, it was observed that GO-enriched microfluidic hydrogels showed more antibacterial performance. Our findings show that the use of a microfluidic system is a promising method to produce GO-enriched wound dressing hydrogels.

4.19. Obtaining Mesh Sizes for Viscoelastic Alginate-Based Hydrogels Using Flory Theory and Saxs

• Joaquín Horacio Palma, Marcos Bertuola, Patricia Carolina Rivas Rojas and Élida Beatriz Hermida
• Institute of Emerging Technologies and Applied Sciences (ITECA), The School of Science and Technology (ECyT) at the National University of San Martín (UNSAM), San Martín, Buenos Aires 1650, Argentina

Natural hydrogels are widely used to create scaffolds that emulate the extracellular matrix of different human tissues, due to their high-water content, good biocompatibility, and bioresorbability. Cell adhesion is directly related to the properties of the scaffold on which the cells grow (artificial extracellular matrix). Some authors have shown that the tensile modulus and mesh size of the extracellular matrix are vital properties for cell proliferation.

This study aims to investigate the mechanical properties of a hydrogel composed of alginate (9% in 1X PBS), cross-linked with 0.5 M Ca²⁺, and a hydrogel composed of 9% alginate, 4.5% gelatin, and 4.5% hyaluronic acid (AGH). The mechanical properties of the hydrogel were measured using a dynamic mechanical analyzer (DMA), and the obtained curves were fitted using a viscoelastic model. The elastic component of the model was used to calculate the mesh size generated by the polymer network; mesh sizes of 6.3 ± 0.1 nm were obtained for the alginate hydrogels and 19.5 ± 0.2 nm for the AGH hydrogel.

On the other hand, the swelling of the hydrogels in a PBS solution with pH 5 was measured after 5 days of immersion. A modification of Flory’s equations, which considers pH-sensitive hydrogels, was used to estimate the mesh size from the swelling tests. Mesh sizes of 2.9 ± 0.1 nm were obtained for alginate hydrogels and 3.5 ± 0.1 nm for AGH hydrogel. These results were related to mesh sizes obtained from SAXS measurements. The obtained curves were adjusted by the Debye–Bueche function, and a characteristic size of 4.15 ± 0.04 nm was obtained for alginate hydrogels and 3.21 ± 0.04 nm for AGH hydrogel.

The incorporation of gelatin and hyaluronic acid increases the mesh size, allowing modulation of the extracellular matrix structure.

4.20. Optimized Enzyme Matrices for 3D-Printed Microneedle Biosensors

• Guillermo Conejo-Cuevas ^1,2, Leire Ruiz-Rubio^1,2, José L. Vilas-Vilela ^1,2 and Francisco Javier del Campo ^1,3

¹ 

BCMaterials, Basque Center for Materials, Applications and Nanostructures, UPV/EHU Science Park, 48940 Leioa, Vizcaya, Spain

² 

Macromolecular Chemistry Group, Department of Physical Chemistry, University of the Basque Country UPV/EHU, Barrio Sarriena s/n, 48940 Leioa, Spain

³ 

IKERBASQUE, Basque Foundation for Science, 48009 Bilbao, Spain

Microneedle (MN) technology offers an advanced approach for minimally invasive biosensing by providing non-painful access to interstitial fluid (ISF) and enabling continuous, real-time monitoring. The dermis (1–3 mm thick) is the skin layer where the ISF content is maximum (40% of the water content is ISF)¹. Thus, MN structures must be in the range from 200 to 1500 µm to penetrate the outer skin layers and reach the ISF.

In this study, MN patches were designed and fabricated via 3D printing; then, MN were transformed into electrodes for electrochemical sensing by gold sputtering. Silver-filled vias were used for electrical interconnection to the potentiostat contacts and Prussian blue (PB) was used as an artificial peroxidase, being electrodeposited on the MN tips to facilitate the detection of glucose and lactate in the presence of their respective oxidase enzymes².

The primary objective of this study was to enhance the performance of these biosensors by optimizing the enzyme immobilization matrix, a crucial determinant of sensor stability and analytical efficiency. Three different biopolymer-based hydrogels—chitosan (CHI), silk fibroin (SF), and methacrylated hyaluronic acid (MeHA)—were evaluated for their ability to maintain enzymatic activity, minimize enzyme leaching, and modulate analyte transport. Diffusion behavior within these matrices was assessed using ferrocyanide as a model electroactive probe on gold microelectrodes. Crosslinking was employed in all hydrogel systems to reinforce structural integrity and promote enzyme retention. The results demonstrate that the choice of immobilization medium significantly affects both sensitivity and dynamic range, providing insights for the development of robust, wearable MN biosensors for applications such as diabetes management.

4.21. Preliminary In Vitro Evaluation of an E-Beam Cross-Linked Doxorubicin-Loaded Hybrid Hydrogel as a Potential Therapy Strategy for Melanoma

• Andreea Mariana Negrescu ¹, Maria Demeter ², Valentina Mitran ¹ and Anisoara Cimpean ¹

¹ 

Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Bucharest, 050095 Bucharest, Romania

² 

National Institute for Lasers, Plasma and Radiation Physics (INFLPR), Atomiştilor 409, 077125 Măgurele, Romania

Polymeric drug delivery systems have gained attention, with hydrogels emerging as promising candidates due to their tunable properties, controllable degradation, and ability to stabilize labile drugs [1]. The literature suggests that hybrid hydrogels, combining synthetic and natural polymers, offer optimal chemical and mechanical properties for medical use [2]. Among crosslinking strategies, electron beam (e-beam) radiation stands out [3], providing precise network control and inherent sterilization without toxic reagents [4]. In this context, hybrid hydrogels of bovine collagen and sodium carboxymethylcellulose (natural) with poly(vinylpyrrolidone) and poly(ethylene oxide) (synthetic) were obtained via e-beam (25 kGy), with doxorubicin loaded before or after irradiation.

The cytotoxic and anti-proliferative effects of these hydrogels, designed to release doxorubicin at its IC50 concentration (10 ng/mL), were evaluated on A375 melanoma cells. The anti-tumour efficiency was assessed via indirect contact studies, using an extraction method (ISO 10993-5 standards), in terms of cell viability (Live/Dead test), proliferation (CCK-8 assay), and morphology (actin staining with Alexa Flour 488–phalloidin).

The results revealed significant differences in cell proliferation among the tested hydrogels, with the lowest OD values observed for the cells grown in the extraction media from the PD81′DOX*/PD81′DOX** samples, and closely followed by the cells maintained in the extraction media from the PD81′ and PD81′DOX samples. This observation, combined with the absence of the red stained cells, indicates either a suppression of metabolic activity or a restriction in cell proliferation. Similarly, cytoskeleton examination showed a decrease in cell density and a more spread-out morphology in cells grown in the PD81′DOX* and PD81′DOX**extraction media, further highlighting the anti-proliferative effect of these hydrogel formulations.

In conclusion, the doxorubicin-loaded hybrid hydrogels exhibit promising anti-tumour potential and could serve as effective drug delivery platforms in melanoma therapy.

Acknowledgements: The authors gratefully acknowledge CNCS—UEFISCDI, project number PN-III-P1-1.1-PD2021-0552, for the financial support.

4.22. Prospects for the Rapid Delivery of Active Pharmaceutical Ingredients to the Brain for Neuroprotective Action: Examples of Nasal Gel Formulations

• Igor Fedorovich Belenichev ¹, Olena Gennadiivna Aliyeva ², Bogdan Serhiyovych Burlaka ³, Nina Viktorivna Bukhtiyarova ⁴ and Kostyantin Petrovych Shabelnik ⁵

¹ 

Department of Pharmacology and Medical Formulation with Course of Normal Physiology, Zaporizhzhia State Medical and Pharmaceutical University, 69035 Zaporizhzhia, Ukraine

² 

Department of Histology, Cytology and Embryology, Zaporizhzhia State Medical and Pharmaceutical University, 69035 Zaporizhzhia, Ukraine

³ 

Department of Medicines Technology, Zaporizhzhia State Medical and Pharmaceutical University, Zaporizhzhia, 69035, Ukraine

⁴ 

Department of Clinical Laboratory Diagnostics and Biological Chemistry, Zaporizhzhia State Medical and Pharmaceutical University, 69035 Zaporizhzhia, Ukraine

⁵ 

Department of Pharmaceutical, Organic and Bioorganic Chemistry, Zaporizhzhia State Medical and Pharmaceutical University, 69035 Zaporizhzhia, Ukraine

Neurological disorders, including cerebrovascular and neurodegenerative diseases, represent one of the most urgent challenges in modern medicine. Despite progress in neuropharmacology, many available drugs exhibit limited clinical efficacy, often due to poor penetration across the blood–brain barrier (BBB) and suboptimal bioavailability. Intranasal drug delivery has emerged as a promising route for non-invasive, rapid CNS targeting. Of special interest are intranasal gel dosage forms, which offer prolonged mucosal contact, improved drug retention, and increasing therapeutic effectiveness. The aim of this study was to develop and preclinically evaluate novel intranasal gel formulations of neuroprotective agents, using in silico modeling and machine learning tools to optimize composition and predict efficacy and safety.

Methods: We have created a new information technology for the in silico substantiation of rational formulations of intranasal dosage forms with neuroprotective effects and developed the expert system “ExpSys Nasalia”. We have created models for the machine learning of binary classification to predict the penetration of APIs through the BBB and to prevent the occurrence of pharmaceutical incompatibilities in the composition of the formulation. Three intranasal gels were formulated with neuroprotective agents: Angiolin, IL-1 receptor antagonist (IL-1ra), and Compound K (a triazoloquinazoline derivative).

Results: The resulting formulations demonstrated high safety in toxicological studies, with no observed local irritation or allergenicity. IL-1ra gel showed superior neuroprotective efficacy compared to citicoline in ischemia and multiple sclerosis models. Angiolin gel improved survival and cognitive outcomes in neonatal rats following prenatal hypoxia. Compound K gel reduced anxiety, improved memory, and exerted antioxidant and anti-apoptotic effects after ketamine anesthesia.

Conclusions: This study demonstrates a successful framework for developing intranasal neuroprotective drugs using information technologies and machine learning. The three novel gels exhibited favorable safety profiles and significant neuroprotective potential in preclinical models, supporting their further development as novel therapeutic options for brain disorders.

4.23. Redox-Responsive Boronic Acid-Based Hydrogel for Controlled Drug Delivery and Theranostic Applications

• Almudena Moreno-Borrallo ¹, Elisabet Gomez-Gonzalez ¹, Thomson Santosh Alex ¹, Binh Than Mai ² and Eduardo Ruiz-Hernandez ¹

¹ 

School of Pharmacy and Pharmaceutical Sciences, Trinity College Dublin, D02 YY50 Dublin, Ireland

² 

School of Biological and Chemical Sciences, University of Galway, Galway, Ireland

Introduction

Redox-responsive biomaterials are gaining traction in drug delivery and theranostics due to their ability to respond to oxidative stress in pathological environments like cancer. Phenylboronic acid (PBA) derivatives are particularly attractive because of their biocompatibility and selective reactivity toward hydrogen peroxide (H₂O₂). We report a novel PBA-based polymer, poly(2-hydroxyethyl methacrylamide-co-phenylboronic acid methyl methacrylamide) (PHMPAMM), which forms injectable hydrogels with polyvinyl alcohol (PVA) for controlled drug release and imaging applications.

Methods

PHMPAMM was synthesized via radical polymerization and characterized by nuclear magnetic resonance. Biocompatibility was evaluated using glioma cell cultures. Hydrogels were prepared by blending PHMPAMM with PVA at optimized ratios and assessed for morphology, viscoelastic properties and redox responsiveness using scanning electron microscopy (SEM), rheology, and 1 mM H₂O₂, respectively. Degradation and drug release studies employed albumin (large molecule), indocyanine green (small molecule), and nanoparticle-based contrast agents.

Results

PHMPAMM exhibited excellent cytocompatibility and formed instant gels when in contact with PVA, suitable for injection via dual-syringe systems. SEM and rheology studies demonstrated excellent structural and injectable properties. Furthermore, the hydrogels degraded significantly faster in oxidative conditions compared to PBS, demonstrating strong redox sensitivity. Lastly, controlled release experiments confirmed efficient encapsulation and sustained release of both large and small therapeutic agents, as well as nanoparticle retention.

Conclusions

PHMPAMM-based hydrogels represent a promising platform for redox-responsive drug delivery and theranostics, particularly in cancer therapy. Their biocompatibility, injectability, and ability to encapsulate and release diverse therapeutic and imaging agents in a controlled manner highlight their potential for clinical translation.

4.24. Surface-Localised Photosensitizer Nanocomposite Hydrogels for Photodynamic Inactivation

• Vinny George and Juraj Bujdak

¹ 

Slovak Academy of Science, Institute of Inorganic Chemistry, Bratislava, Slovakia

² 

Department of Physical and Theoretical Chemistry, Faculty of Natural Sciences, Comenius University in Bratislava, SK-842 15 Bratislava, Slovakia

An escalation in antimicrobial drug resistance among pathogens has driven the need to develop alternative treatment methods. Photodynamic inactivation (PDI) is a promising antibiotic-free antimicrobial strategy. Hydrogels have proven their effectiveness as delivery systems for photosensitizers (PSs) in antimicrobial PDI. Despite increasing interest, PS-loaded hydrogels encounter several challenges, including limited light penetration and issues with the solubility, stability, and bioactivity of many PSs under physiological conditions [1]. Moreover, achieving a uniform distribution of photosensitiser (PS) molecules within hydrogels remains a significant challenge during fabrication. Smectites are low-cost, eco-friendly inorganic hosts that have proven to be effective for many photosensitiser (PS) molecules, preserving their fluorescence and photoactivity, improving dye stability, and reducing photodegradation [2]. This study intercalated the photosensitiser phloxine B (PhB) into organically modified synthetic saponite (Sap) with different surfactants as the primary host material. Thin films with a thickness in the micrometre range were subsequently prepared using vacuum filtration. The hydrogel precursor, composed of dissolved poly(vinyl alcohol) (PVA) and glycerol as a crosslinker, was cast onto the freshly prepared film placed in a mould to partially penetrate and swell the organoclay layer. A thin nanocomposite film on the surface of the hydrogel was formed during the crosslinking process, forming surface-functionalised hydrogel [3]. This approach offers greater precision in PS loading and distribution than bulk incorporation, concentrating the active substance at the surface. Absorption and luminescence spectroscopy revealed a direct relationship between PhB loading and absorbance, and an inverse relationship with fluorescence intensity, indicating concentration quenching and molecular aggregation. X-ray diffraction confirmed structural changes upon PhB intercalation and nanocomposite formation, while infrared spectroscopy verified the presence of the components in the composites without significant chemical alteration. This novel approach involving surface-modified hydrogels enables controlled PS loading and distribution through a simple fabrication process, potentially advancing the therapeutic effectiveness of PDI-based hydrogels.

4.25. The Creation of a Docetaxel-Loaded Hydrogel Nanosponge for the Treatment of Malignant Melanoma

• Pritam Kayal and Hirakjyoti Das
• Department of Pharmaceutics, Bharat Pharmaceutical Technology, Amtali, Agartala, Tripura(w), India

Introduction: The second most prevalent non-melanoma skin cancer in the world, squamous cell carcinoma, is mostly caused by exposure to UV light. Surgery, radiation, and chemotherapy are examples of current therapeutic modalities; these methods frequently have drawbacks in terms of toxicity and patient compliance. Poor solubility and absorption make the administration of curcumin, a natural substance with proven anticancer effects, a topical method. The purpose of this work is to describe a curcumin-loaded nanoemulsion gel technology for improved topical administration in the treatment of SCC.

Methods: The spontaneous emulsification process was used to create curcumin nanoemulsions. Surfactant and co-surfactant screening found appropriate emulsifying agents, and solubility tests were used to choose the best oil phase. Different ratios of oil-to-surfactant/co-surfactant were assessed. Particle size analysis, zeta potential measurement, thermodynamic stability testing, and polydispersity index calculation were performed on the chosen formulations. The carbopol gel matrix was filled with optimized nanoemulsions, which were then assessed for cytotoxicity using the MTT assay, in vitro drug release using Franz diffusion cells, drug content, entrapment efficiency, and physical properties.

Results: Capmul CMC was chosen as the oil phase since it showed the maximum amount of curcumin solubility (90 ± 0.18 mg/mL). The surfactant was Tween 20, and the co-surfactant was PEG 400. F6 (oil/SCOS 1:6) and F8 (oil/SCOS 1:8) were two formulations that underwent optimization. With a globule size of 125.3 nm, a zeta potential of −18.3 mV, and a PDI of 0.310, F8 demonstrated exceptional qualities. For the F8 formulation, the nanoemulsion gel demonstrated 99% entrapment efficiency. According to in vitro release experiments, F8 released 59.41% more medication over a 24-h period than F6, which released 66.11%. According to cytotoxicity testing, the F8 formulation’s IC50 value was 59.63 µg/mL.

Conclusion: When compared to traditional therapies, the proposed curcumin nanoemulsion gel method effectively improved drug solubility and offered sustained release features appropriate for topical SCC treatment, including decreased systemic toxicity and improved patient compliance.

5. Session 5: Gels in Electro-Magneto-Mechanical Devices, 3D Printing, and Manufacturing

5.1. Optimization of Cross-Linked Pva Functionalized with Pani: In Situ Strategies to Design Electro-Conductive Fibrous Platforms for Brain Applications

• Aldobenedetto Zotti ¹, Nergis Zeynep Renkler ¹, Mario BARRA ², Stefania Scialla ¹, Simona Zuppolini ¹, Anna Borrielo ¹, Vincenzo Guarino ¹

¹ 

Institute of Polymers Composites and Biomaterials (IPCB) National Research Council of Italy, Mostra d’Oltremare Pad. 20, V.le J. F. Kennedy 54, 80125 Naples, Italy

² 

Institute for Superconductors, Innovative Materials, and Devices, National Research Council of Italy and Dipartimento di Fisica “Ettore Pancini”, P. le Tecchio, 80, 80125 Napoli, Italy

Polyelectrolyte hydrogels such as polyvinyl alcohol (PVA) can be combined with conductive polymers to create bioactive and electrically responsive materials for biomedical use. In this study, we prepared PVA hydrogel in the form of electrospun nanofibrous mats containing two different forms of polyaniline (PANI)—emeraldine base (EB-PANI) and PANI nano short fibers (PANI-NF)—and evaluated their morphology, electrical behavior, and biological response. Citric acid was used as a crosslinker to improve the water stability and structural integrity of the electrospun mats.

Electrospinning was carried out using PVA/PANI blends, followed by a short thermal treatment to activate crosslinking. The obtained fibers were analyzed by SEM, which showed uniform morphologies. Pure PVA fibers had an average diameter of about 0.53 µm, while the addition of PANI slightly increased the fiber size (0.65 µm for EB-PANI and 0.72 µm for PANI-NF). Electrical tests indicated conductivity values between 10⁻⁸ and 10⁻⁷ S/cm. Non-crosslinked samples showed generally higher conductivity, while crosslinking affected EB-PANI and PANI-NF differently: EB-PANI maintained stable values, whereas PANI-NF displayed reduced conductivity, probably linked to their different protonation and charge transport mechanisms. In vitro experiments with SH-SY5Y neuroblastoma cells confirmed that all scaffolds were cytocompatible and supported cell adhesion and proliferation up to 14 days, with no signs of toxicity.

These results show that PVA/PANI hydrogel-based nanofibers can be considered as conductive and biocompatible scaffolds, suitable for applications in the brain field. The comparison between EB-PANI and PANI-NF highlights the role of PANI structure on conductivity and provides useful information for optimizing electro conductive platforms.

5.2. Microstructural, Textural, and Rheological Properties of Edible Bigels Designed for 3D Food Printing

• Konstantina Zampouni, Triantafyllia Biza, Danai Morfidou, Thomas Moschakis and Eugenios Katsanidis
• Department of Food Science and Technology, School of Agriculture, Faculty of Agriculture, Forestry and Natural Environment, Aristotle University of Thessaloniki, Thessaloniki, Greece

Three-dimensional (3D) food printing is an emerging technology in food processing, offering high flexibility and customization to meet the growing demand for personalized nutrition and innovative product designs. Bigels, semi-solid systems composed of a hydrogel and an oleogel, present a promising approach as edible inks for extrusion-based 3D food printing due to their structural and functional properties.

This study aimed to develop and characterize edible bigel inks with optimized properties for 3D food printing applications. Bigels were prepared by blending beeswax (6%)–monoglycerides (4%) sunflower oil oleogels with gelatin (4%)–guar gum (1%) hydrogels at varying ratios (0–50%). Their microstructural, textural, and rheological characteristics were evaluated to assess printability and structural integrity.

Polarized light microscopy revealed distinct microstructures with increasing oleogel content, shifting from oleogel-in-hydrogel systems to bicontinuous networks. Textural analysis using a forward extrusion test demonstrated that oleogel content significantly influenced firmness and extrusion force, key parameters for 3D printing performance. Rheological analyses, including flow curve assessments and amplitude and frequency sweep tests, confirmed that all formulations exhibited pronounced shear-thinning behavior and predominantly elastic properties (G′ > G″). These features are critical for smooth extrusion and maintaining structural stability post-printing. Furthermore, the 3-Interval Thixotropy Test (3ITT) evaluated structural recovery under shear, showing improved recovery percentages at higher oleogel concentrations.

These findings highlight the potential of bigels as functional and customizable inks for 3D food printing, enabling the development of novel food products with tailored textural and nutritional attributes.

5.3. Sulfidation-MnO₂ Dual-Modified Cu-Co-MOFs for Flexible Supercapacitors with Hydrogel Electrolyte

• Jiale Hou, Cheng Chen and Donghai Lin
• School of Energy and Materials, Shanghai Polytechnic University, Shanghai 201209, China

Metal–organic frameworks (MOFs) have garnered significant attention as advanced energy storage materials owing to their exceptional specific surface area and structurally tailorable properties. Nevertheless, their practical implementation faces critical limitations, including intrinsic poor electrical conductivity and inadequate structural stability. To address these challenges, this study proposes an innovative dual-modification strategy integrating controlled sulfidation with conformal MnO₂ coating. Initially, bimetallic Cu-Co-MOF nanoarchitectures were hydrothermally synthesized on nickel foam substrates. Subsequent sulfidation treatment transformed the precursor into Cu-Co-S ternary compounds, effectively optimizing electronic band structures and achieving a 3.8-fold conductivity enhancement. Through rapid electrochemical deposition, ultrathin MnO₂ nanosheets were uniformly constructed on Cu-Co-S surfaces, forming hierarchical heterojunctions. This dual-engineering (1) substantially reinforced mechanical stability via protective coating, (2) established built-in interfacial electric fields, accelerating electron transfer kinetics (charge transfer resistance reduced by 67%), and (3) provided abundant electroactive sites for ion adsorption. The optimized Cu-Co-S@MnO₂ electrode delivered an outstanding electrochemical performance, including a high specific capacitance of 1842 F g⁻¹ at 1 A g⁻¹ and 91.3% capacitance retention after 10,000 cycles. When configured into a flexible asymmetric supercapacitor (FASC) employing polyvinyl alcohol (PVA)/KOH hydrogel electrolyte, the device achieved remarkable energy density of 68.4 Wh kg⁻¹ at 850 W kg⁻¹ power density, along with 88.7% capacity retention over 15,000 bending cycles. These results validate the dual-modification strategy’s efficacy in developing mechanically robust, high-performance flexible energy storage systems for next-generation wearable electronics.

6. Session 6: Gels in Chemical Processing, Energy, and Environment

6.1. Bi₂O₄/Polyaniline Thin Films Doped with Magnesia for Multipurpose Uses: Synthesis and Applications

• Alvena Shahid
• Department of Physics, Lahore College for Women University, Lahore, Pakistan

One of the most difficult problems the world is currently experiencing is climate change. The long-term, localized effects of global warming are clear in the domains of politics, science, society, ethics, and economics. Renewable energy sources and energy storage devices are potential solutions to this problem. The current work highlights the role that metal oxide supercapacitors play in the creation of sustainable energy sources. This aligns with many of the Sustainable Development Goals (SDGs), such as Goal 13 (Climate Action) and Goal 7 (Affordable and Clean Energy). Metal oxide thin film is a useful tool for scientists due to its many uses in electrical device performance, environmental remediation, materials development, and transdisciplinary research. The Sol–gel dip-coating method was used to create magnesium-doped bismuth oxide (Bi₂O₄) thin films for the study. The monoclinic Bi₂O₄ phase was confirmed to be present in all thin films using X-ray diffraction spectra. Using Fourier transform infrared spectroscopy, the functional bonds of bismuth oxide were verified in the range of around 460 to 580 cm⁻¹. The bandgap of undoped and Magnesia-doped Bi₂O₄ films was found to be between 2.2 and 1.97 eV. For the Magnesia–Bi₂O₄ films to be used as window layers in solar cells, this range was needed. Magnesia-doped Bi₂O₄ performs better photocatalytically than undoped Bi₂O₄, most likely as a result of better charge separation and transfer. Exposure to visible light accelerates the breakdown of organic contaminants. Further investigation is needed to find the best doping concentration and investigate various approaches to improve the photocatalytic capabilities of Bi₂O₄. According to this study’s findings, Magnesia-doped Bi₂O₄ has a lot of potential uses in water purification and environmental remediation. This substance contributes to the achievement of sustainable development goals by offering a useful and affordable method of water treatment.

6.2. Polysaccharide-Based Decontamination Gels for the Radioactive Decontamination of Metal Parts Within Radioactive Waste Management

• Alberto Alejandro Pujol Pozo and Fabiola Monroy Guzmán
• Radioactive Waste Department, National Institute of Nuclear Research, 52750 State of Mexico, Mexico

Within the nuclear industry, the issue of radioactive waste management is of vital importance. Therefore, it is necessary to have methods and tools that allow for the treatment of contaminated materials without compromising worker health and that are economically viable. This work focuses on the synthesis of gels based on natural polysaccharides, which can form easily removable polymeric films and can decontaminate metal surfaces contaminated with radionuclides. Decontamination aims to remove or reduce contaminants (sometimes in combination with other hazardous materials) present on the surfaces of pipes, tools, glove boxes, radioactive cells, structures, and equipment such as rotors, motors, centrifuges, pumps, pump heads, columns, etc.

The use of polysaccharide-based decontamination gels is one of the currently available chemical decontamination treatment methods. It offers several advantages, such as lower operating costs during decontamination processes, lower risk for occupationally exposed personnel, no need to install a sealed system, and the gels being biodegradable. The use and development of decontamination gels contribute to reducing radioactive waste management costs and improving treatment.

Gels composed of different polysaccharides were tested to evaluate their decontamination properties on stainless steel surfaces and were evaluated by obtaining decontamination factors (DF). Gels containing 2.8% chitosan, 6% sodium alginate, 1% guar gum + 3% hydroxyethyl-cellulose, and 3% pectin were synthesized.

Decontamination tests on stainless steel specimens were positive, with high DF values obtained for various radionuclides, demonstrating the gels’ ability to decontaminate metal surfaces and the high efficiency of the decontamination process. Radionuclides such as Nd-147 on stainless steel stood out, with very high Fd values. Similarly, high Fd values were obtained for Co-58 and Hf-181. The DF values in the decontamination process depend on the type of gel applied, the contaminating radionuclide, and the surface to be decontaminated.

6.3. Recent Advancements in Gel Materials for Green Chemical Processes, Clean Energy, and Environmental Solutions

• Annu Yadav
• Department of Applied Chemistry, Delhi Technological University, Delhi 110042, India

Gel-based materials have recently emerged as versatile platforms for addressing challenges in green chemical processes, clean energy, and environmental remediation. Their three-dimensional polymeric networks, high liquid-holding capacity, and tunable physicochemical properties make them adaptable to multiple sustainable applications.

In our work, we focused on the design and functionalization of gels derived from bio-based polymers and ionic liquids to create eco-friendly alternatives for chemical processing. Our experimental results demonstrated that ionogels not only improved catalyst retention but also enhanced reaction selectivity, leading to reduced solvent usage and lower waste generation. Similarly, organogel-supported catalytic systems were successfully tested in esterification reactions, achieving higher yields under mild conditions compared to conventional methods.

In the energy domain, we developed gel polymer electrolytes with optimized porosity and surface functionality. Electrochemical studies revealed improved ionic conductivity and thermal stability, which translated into better cycling performance of prototype lithium-ion cells. Notably, the gels retained flexibility and stability even after multiple charge–discharge cycles, with only a minor decrease in conductivity.

For environmental applications, we fabricated bio-inspired hydrogels functionalized with natural additives. Adsorption experiments confirmed their efficiency in removing heavy metals and organic dyes from water, with recyclability over several cycles showing only a slight decline in adsorption capacity.

This integrated investigation underscores the potential of gel-based materials as sustainable, multifunctional systems that bridge green chemistry, clean energy, and environmental solutions.

6.4. Synergistic Stabilization and Rheology of Sodium Alginate Gel Foams for Subsurface Carbon Storage and Enhanced Oil Recovery

• Tongke Zhou
• Department of Chemical Engineering, School of Engineering, University of Manchester, Manchester, UK

Sodium alginate (SA) gel foams are gaining attention as high-performance fluids for subsurface applications, including geological carbon storage and enhanced oil recovery (EOR). In this study, we systematically investigate the synergistic stabilisation and rheological behaviour of sodium alginate gel foams with eco-friendly foaming agents. A series of gel foams were prepared by varying the surfactant and SA concentration and the type of crosslinking agents. The foam stability and rheological properties were evaluated under different salinity and temperature conditions to simulate reservoir environments. Foam drainage time and coarsening behaviours were used to estimate stability, while oscillatory and steady-state rheological tests were conducted to characterise viscoelasticity and flow behaviour. The results reveal that both the concentration of SA and the type of crosslinker significantly influence the gel network structure and foam stability. The rheological measurements show that the optimised gel foams exhibit non-Newtonian behaviour and high elasticity, which are essential for controlling mobility in porous media. These findings provide fundamental insights into the design of stable, biodegradable gel foams tailored for harsh subsurface conditions. This study also highlights the potential of combining natural polymers with green surfactants to develop environmentally friendly formulations with tunable properties, offering new strategies for sustainable reservoir engineering and fluid control technologies.

6.5. Synthesis of Advanced Biopolymers Through Chemo-Selective Approach for Enhanced Oil Recovery from Non-Producing Reservoirs

• Abhishek Tyagi and Akhil Agrawal
• Department of Microbiology, School of Life Sciences, Central University of Rajasthan, Ajmer 305817, India

The production of crude oil must be increased to meet the growing global energy demand. As crude oil will remain a dominant energy source for the next ~30 years, enhanced oil recovery (EOR) has become essential to maximize output from existing reservoirs, which is more economical than drilling new wells. Conventional recovery methods are inefficient, leaving behind nearly 50% of the original oil. Within EOR, biopolymers are emerging as sustainable alternatives due to their accessibility, cost-effectiveness, viscoelastic behaviour, and biodegradability. Natural polymers such as guar gum, xanthan gum, welan gum, scleroglucan, schizophyllan, and gum tragacanth are increasingly being investigated to replace synthetic polymers. However, microbial deterioration, shear-stress instability, and sensitivity to reservoir conditions (temperature, salinity, concentration, and functional groups) restrict their widespread application. This study introduces a novel chemically tailored biopolymer for EOR from non-producing reservoirs. While conventional polymers like polyacrylamide and xanthan gum typically achieve only 4–5% incremental recovery, our preliminary results demonstrate up to 10% additional recovery. The polymer is structurally modified through graft copolymerization, gel modification, esterification, crosslinking, and nanocomposite functionalization, ensuring higher viscosity, stability, and reservoir compatibility. The formulations will be developed using single or modified polymers along with oilfield adjuvants after validation under simulated reservoir conditions. Even a 1–2% incremental recovery can translate into millions of additional barrels of oil, highlighting the scalability and economic relevance of this approach. Recently, chemo-selectively modified and thermo-viscosifying polymers further support enhanced sweep efficiency under harsh conditions through viscosity increment, wettability alteration, and emulsification. These polymers have been successfully investigated in both laboratory experiments and field trials, highlighting their strong potential for large-scale EOR applications.

“Towards Sustainable Oil Recovery: Biopolymer Solutions for Energy Efficiency”