Gels | January 2026 - Browse Articles

22 pages, 7417 KB

Open AccessArticle

Exploring the Potential of Polyvinyl Alcohol–Borax-Based Gels for the Conservation of Historical Silk Fabrics by Comparative Cleaning Tests on Simplified Model Systems

by Ehab Al-Emam, Marta Cremonesi, Natalia Ortega Saez, Hilde Soenen, Koen Janssens and Geert Van der Snickt

Gels 2026, 12(1), 97; https://doi.org/10.3390/gels12010097 - 22 Jan 2026

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Abstract

Cleaning historical silk textiles is a particularly sensitive operation that requires precise control to prevent mechanical or chemical damage. In this study, we investigate using flexible PVA–borax-based gels to remove soot from silk, i.e., polyvinyl alcohol–borax (PVA-B) gels and polyvinyl alcohol–borax–agarose double network [...] Read more.

Cleaning historical silk textiles is a particularly sensitive operation that requires precise control to prevent mechanical or chemical damage. In this study, we investigate using flexible PVA–borax-based gels to remove soot from silk, i.e., polyvinyl alcohol–borax (PVA-B) gels and polyvinyl alcohol–borax–agarose double network gels (PVA-B/AG DN) loaded with different cleaning agents—namely, 30% ethanol and 1% Ecosurf EH-6—in addition to plain gels loaded with water. These gel formulations were tested on simplified model systems (SMS) and were applied using two methods: placing and tamping. The cleaning results were compared with a traditional contact-cleaning approach; micro-vacuuming followed by sponging. Visual inspection, 3D opto-digital microscopy, colorimetry, and machine-learning-assisted (ML) soot counting were exploited for the assessment of cleaning efficacy. Rheological characterization provided information about the flexibility and handling properties of the different gel formulations. Among the tested systems, the DN gel containing only water, applied by tamping, was easy to handle and demonstrated the highest soot-removal effectiveness without leaving residues, as confirmed by micro-Fourier Transform Infrared (micro-FTIR) analysis. Scanning electron microscope (SEM) micrographs proved the structural integrity of the treated silk fibers. Overall, this work allows us to conclude that PVA–borax-based gels offer an effective, adaptable, and low-risk cleaning strategy for historical silk fabrics. Full article

(This article belongs to the Special Issue Advances in the Design and Application of Gels in Heritage Conservation)

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20 pages, 7928 KB

Open AccessArticle

Annealing-Fabricated Poria cocos Glucan-Tannic Acid Composite Hydrogels: Integrated Multifunctionality for Accelerated Wound Healing

by Yong Gao, Ruyan Qian, Chenyi Feng, Dan Li, Xinmiao He, Wengui Xu, Jiaxin Zhu and Zongbao Zhou

Gels 2026, 12(1), 96; https://doi.org/10.3390/gels12010096 - 22 Jan 2026

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Abstract

Multifunctional wound dressings integrating moisture retention, antibacterial activity, and bioactive delivery are in demand, yet balancing structural stability and functional synergy in polysaccharide hydrogels remains a challenge. This study focused on developing such advanced dressings. Poria cocos glucan (PCG) hydrogels were fabricated via [...] Read more.

Multifunctional wound dressings integrating moisture retention, antibacterial activity, and bioactive delivery are in demand, yet balancing structural stability and functional synergy in polysaccharide hydrogels remains a challenge. This study focused on developing such advanced dressings. Poria cocos glucan (PCG) hydrogels were fabricated via annealing, with PCG-4 (4 wt.%) identified as the optimal matrix. PCG-tannic acid (TA) composite hydrogels were subsequently prepared via TA loading, followed by systematic property characterization and in vivo wound healing evaluation in a rat full-thickness wound model. The composite hydrogel exhibited balanced porosity (56.7 ± 3.4%) and swelling (705.5 ± 11.3%), along with enhanced mechanical rigidity. It enabled temperature-responsive TA release, coupled with high antioxidant activity and antibacterial efficacy. Additionally, it showed excellent biocompatibility (hemolysis rate <2%; NIH-3T3 cell viability >98%) and accelerated rat wound closure with enhanced collagen deposition, suggesting a beneficial combined effect of the composite’s components. PCG-TA holds promise as an advanced wound dressing, and the scalable annealing fabrication strategy supports its translational application potential. Full article

(This article belongs to the Special Issue Biopolymer Hydrogels: Synthesis, Properties and Applications)

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17 pages, 4950 KB

Open AccessArticle

Effect of Driving Pressure Modes on Microjet Dispersion Characteristics in Tissue-Mimicking Gels for Large-Volume Needle-Free Injection

by Dongping Zeng, Longsheng Luo, Linxing Luo, Wei Wang and Jiamin Li

Gels 2026, 12(1), 95; https://doi.org/10.3390/gels12010095 - 22 Jan 2026

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Abstract

Needle-free injection (NFI) technology is a promising alternative to conventional syringe injection, as it mitigates needle-related complications and enhances patient compliance. However, achieving the controlled and efficient dispersion of larger-volume formulations (>1 mL) within tissues remains a significant challenge. This study presents a [...] Read more.

Needle-free injection (NFI) technology is a promising alternative to conventional syringe injection, as it mitigates needle-related complications and enhances patient compliance. However, achieving the controlled and efficient dispersion of larger-volume formulations (>1 mL) within tissues remains a significant challenge. This study presents a novel pneumatic NFI system that uses a two-phase driving mode to regulate driving pressure and duration with an ejection volume of 1.0–2.0 mL. The integrated pressure stabilization unit significantly reduces pressure fluctuations during the initial injection phase, generating a more stable and uniform spray distribution. It is designed to produce an ideal elliptical dispersion effect while eliminating splatter, enabling controlled large-volume delivery. Jet impact experiments were conducted to investigate the dynamic characteristics of microjets generated by conventional single-phase and novel two-phase driving modes. Furthermore, the influence of the driving mode on the dispersion behaviors of microjets in agarose gels was explored through high-speed imaging of gel injections. The results demonstrate that the two-phase driving mode produces a distinct two-phase jet pressure profile. Compared to the single-phase mode, the two-phase mode produced a significantly larger dispersion width at equivalent initial driving pressures. This promotes more uniform lateral drug distribution and achieves a higher percentage of liquid drug delivery in gels. Furthermore, favorable driving pressure combinations were identified for different volumes: (1.25–0.25) MPa for 1.0 mL, (1.25–0.50) MPa for 1.5 mL, and (1.50–0.50) MPa for 2.0 mL. This provides a practical basis for optimizing clinical parameters and advancing the development of controllable NFI systems. Full article

(This article belongs to the Special Issue Recent Advances in Biopolymer Gels (2nd Edition))

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20 pages, 3995 KB

Open AccessArticle

Role of Starch Type in Gel-like Network Formation of Extruded Meat Analogs

by Chaeyeon Kang, Ayeon Han and Bon-Jae Gu

Gels 2026, 12(1), 94; https://doi.org/10.3390/gels12010094 - 22 Jan 2026

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Abstract

Starches play a crucial role in determining the expansion, texture, and structural development of extruded meat analogs through their gelatinization behavior and interactions with proteins. In this study, corn, pea, tapioca, sweet potato, and potato starches were incorporated into soy protein-based formulations and [...] Read more.

Starches play a crucial role in determining the expansion, texture, and structural development of extruded meat analogs through their gelatinization behavior and interactions with proteins. In this study, corn, pea, tapioca, sweet potato, and potato starches were incorporated into soy protein-based formulations and processed under low-moisture and high-moisture extrusion conditions to investigate starch-dependent physicochemical properties. Amylose/amylopectin composition and starch pasting properties were evaluated, and the resulting extrudates were characterized in terms of expansion behavior, water-related properties, textural attributes, and internal structure. Distinct differences in pasting behavior were observed among starches, with potato starch exhibiting high peak viscosity and pea starch showing strong viscosity development during cooling. These differences were closely associated with extrusion outcomes, influencing expansion ratio and texture formation. In low-moisture extrusion, starches susceptible to thermal and shear degradation showed increased solubilization, whereas in high-moisture extrusion, enhanced starch gelatinization promoted starch–protein interactions and contributed to improved textural integrity and structural alignment. Overall, the results demonstrate that starch type is a key determinant of expansion behavior, texture, and structural organization in extruded meat analogs, highlighting the importance of starch selection and processing conditions for tailoring product quality. Full article

(This article belongs to the Special Issue Food Gels: Fabrication, Characterization, and Application (2nd Edition))

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17 pages, 2144 KB

Open AccessArticle

Dual-Channel Extrusion-Based 3D Printing of a Gradient Hydroxyapatite Hydrogel Scaffold with Spatial Curved Architecture

by Yahao Wang, Yongteng Song, Qingxi Hu and Haiguang Zhang

Gels 2026, 12(1), 93; https://doi.org/10.3390/gels12010093 - 21 Jan 2026

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Abstract

A biomimetic cartilage scaffold featuring a continuous hydroxyapatite (HA) concentration gradient and a spatially curved architecture was developed using a dual-channel mixing extrusion-based 3D printing approach. By dynamically regulating the feeding rates of two bioinks during printing, a continuous HA gradient decreasing from [...] Read more.

A biomimetic cartilage scaffold featuring a continuous hydroxyapatite (HA) concentration gradient and a spatially curved architecture was developed using a dual-channel mixing extrusion-based 3D printing approach. By dynamically regulating the feeding rates of two bioinks during printing, a continuous HA gradient decreasing from the bottom to the top of the scaffold was precisely achieved, mimicking the compositional transition from the calcified to the non-calcified cartilage region in native articular cartilage. The integration of gradient material deposition with synchronized multi-axis motion enabled accurate fabrication of curved geometries with high structural fidelity. The printed scaffolds exhibited stable swelling and degradation behavior and showed improved compressive performance compared with step-gradient counterparts. Rheological analysis confirmed that the bioinks possessed suitable shear-thinning and recovery properties, ensuring printability and shape stability during extrusion. In vitro evaluations demonstrated good cytocompatibility, supporting bone marrow mesenchymal stem cell (BMSC) adhesion and proliferation. Chondrogenic assessment based on scaffold extracts indicated that the incorporation of HA and its gradient distribution did not inhibit cartilage-related extracellular matrix synthesis, confirming the biosafety of the composite hydrogel system. Overall, this study presents a controllable and versatile fabrication strategy for constructing curved, compositionally graded cartilage scaffolds, providing a promising platform for the development of biomimetic cartilage tissue engineering constructs. Full article

(This article belongs to the Section Gel Chemistry and Physics)

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16 pages, 7724 KB

Open AccessArticle

Hydroxyapatite-Mediated Mechanical Modulation of GelMA Hydrogels Influences Osteogenic Differentiation of 3D Spheroids

by Narantungalag Amarbayasgalan, Ji Hyeon Kim, Won-Gun Koh, Karthika Muthuramalingam and Hyun Jong Lee

Gels 2026, 12(1), 92; https://doi.org/10.3390/gels12010092 - 20 Jan 2026

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Abstract

Substrate stiffness critically regulates osteogenic differentiation, yet systematic identification of optimal mechanical conditions in three-dimensional culture remains limited. This study investigated how hydroxyapatite (HAp)-mediated mechanical modulation of gelatin methacryloyl (GelMA) hydrogels influences osteogenic differentiation of encapsulated SAOS-2 spheroids. GelMA hydrogels with HAp at [...] Read more.

Substrate stiffness critically regulates osteogenic differentiation, yet systematic identification of optimal mechanical conditions in three-dimensional culture remains limited. This study investigated how hydroxyapatite (HAp)-mediated mechanical modulation of gelatin methacryloyl (GelMA) hydrogels influences osteogenic differentiation of encapsulated SAOS-2 spheroids. GelMA hydrogels with HAp at 5, 10, and 15 μg/mL were characterized for mechanical properties and used to encapsulate pre-formed spheroids under osteogenic conditions. GelMA+HAp5 achieved the highest compressive modulus, while higher HAp concentrations reduced crosslinking efficiency. All formulations maintained comparable viability and metabolic activity. Notably, GelMA+HAp10 produced the highest alkaline phosphatase activity at Days 7 and 14, despite lower stiffness than GelMA+HAp5, demonstrating a non-linear relationship between substrate mechanics and osteogenic response. These results establish that optimizing rather than maximizing mechanical properties represents a more effective scaffold design strategy for bone tissue engineering. Full article

(This article belongs to the Special Issue Hydrogel for Tissue Engineering and Biomedical Therapeutics (2nd Edition))

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12 pages, 3406 KB

Open AccessArticle

A 3D Collagen–Alginate Hydrogel Model for Mechanoregulation of Autophagy in Periodontal Ligament Cells

by Xueping Kang, Bei Gao, Tong Wang, Qingbo Zhao, Shiyang Wu, Chuqi Li, Hui Zhang, Rui Zou and Yijie Wang

Gels 2026, 12(1), 91; https://doi.org/10.3390/gels12010091 - 20 Jan 2026

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Abstract

Mechanical loading is a central cue in periodontal tissues, where compression of the periodontal ligament guides remodeling and orthodontic tooth movement (OTM). However, most mechanobiology studies have used two-dimensional cultures with poorly defined loading, and the role of autophagy under realistic three-dimensional compression [...] Read more.

Mechanical loading is a central cue in periodontal tissues, where compression of the periodontal ligament guides remodeling and orthodontic tooth movement (OTM). However, most mechanobiology studies have used two-dimensional cultures with poorly defined loading, and the role of autophagy under realistic three-dimensional compression remains unclear. In this study, we constructed a three-dimensional static compression model by encapsulating human periodontal ligament cells in collagen–alginate–CaSO₄ hydrogels, whose swelling, degradation, and viscoelasticity approximate those of native matrix. When exposed to a controlled static compressive stress, the cells exhibited an early autophagic response with increased ATG7, Beclin1, and LC3-II/LC3-I; accumulation of LC3-positive puncta; and reduced p62 expression between 4 and 8 h. Pharmacological modulation showed that activation of AKT-mTOR signaling suppressed this response, whereas its inhibition further augmented autophagy, identifying AKT-mTOR as a negative regulator of compression-induced autophagy. Together, these findings demonstrate that moderate static compression drives AKT-mTOR-dependent autophagy in periodontal ligament cells and establish a simple hydrogel platform for quantitative studies of periodontal remodeling. Full article

(This article belongs to the Special Issue Innovations in Application of Biofunctional Hydrogels)

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27 pages, 16684 KB

Open AccessArticle

pH-Sensitive Dextrin-Based Nanosponges Crosslinked with Pyromellitic Dianhydride and Citric Acid: Swelling, Rheological Behavior, Mucoadhesion, and In Vitro Drug Release

by Gjylije Hoti, Sara Er-Rahmani, Alessia Gatti, Ibrahim Hussein, Monica Argenziano, Roberta Cavalli, Anastasia Anceschi, Adrián Matencio, Francesco Trotta and Fabrizio Caldera

Gels 2026, 12(1), 90; https://doi.org/10.3390/gels12010090 - 19 Jan 2026

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Abstract

Dextrin-based nanosponges (D-NS) are promising candidates for oral drug delivery due to their biocompatibility, mucoadhesive properties, and tunable swelling behavior. In this study, pH-sensitive nanosponges were synthesized using β-cyclodextrin (β-CD), GluciDex^®2 (GLU2), and KLEPTOSE^® Linecaps (LC) as building blocks, crosslinked [...] Read more.

Dextrin-based nanosponges (D-NS) are promising candidates for oral drug delivery due to their biocompatibility, mucoadhesive properties, and tunable swelling behavior. In this study, pH-sensitive nanosponges were synthesized using β-cyclodextrin (β-CD), GluciDex^®2 (GLU2), and KLEPTOSE^® Linecaps (LC) as building blocks, crosslinked with pyromellitic dianhydride (PMDA) and citric acid (CA). The nanosponges were mechanically size-reduced via homogenization and ball milling, and characterized by FTIR, TGA, dynamic light scattering (DLS), and zeta potential measurements. Swelling kinetics, cross-linking density (determined using Flory–Rehner theory), rheological behavior, and mucoadhesion were evaluated under simulated gastric and intestinal conditions. The β-CD:PMDA 1:4 NS was selected for drug studies due to its optimal balance of structural stability, swelling capacity (~863% at pH 6.8), and highest apomorphine (APO) loading (8.23%) with 90.58% encapsulation efficiency. All nanosuspensions showed favorable polydispersity index values (0.11–0.30), homogeneous size distribution, and stable zeta potentials, confirming suspension stability. Storage at 4 °C for six months revealed no changes in physicochemical properties or apomorphine (APO) degradation, indicating protection by the nanosponge matrix. D-NS exhibited tunable swelling, pH-responsive behavior, and mucoadhesive properties, with nanoparticle–mucin interactions quantified by the rheological synergism parameter (∆G′ = 53.45, ∆G″ = −36.26 at pH 6.8). In vitro release studies demonstrated slow, sustained release of APO from D-NS in simulated intestinal fluid compared to free drug diffusion, highlighting the potential of D-NS as pH-responsive, mucoadhesive carriers with controlled drug release and defined nanoparticle–mucin interactions. Full article

(This article belongs to the Special Issue Functional Gel Materials: Chemistry, Processing, Mechanical Performance, and Applications)

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21 pages, 5051 KB

Open AccessArticle

High-Temperature Gelation and Structural Characterisation of Commercial Yellow Pea, Faba Bean, and Mungbean Protein–Starch Systems

by Niorie Moniharapon, Minqian Zhu, Lucinda Daborn and Sushil Dhital

Gels 2026, 12(1), 89; https://doi.org/10.3390/gels12010089 - 19 Jan 2026

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Abstract

The heating of plant proteins at high temperatures is often associated with phase separation due to the aggregation of protein fractions, resulting in weak or discontinuous gels in liquid processing systems. This study examined the high-temperature gelation behaviour of commercial yellow pea, faba [...] Read more.

The heating of plant proteins at high temperatures is often associated with phase separation due to the aggregation of protein fractions, resulting in weak or discontinuous gels in liquid processing systems. This study examined the high-temperature gelation behaviour of commercial yellow pea, faba bean, and mungbean protein isolates and evaluated how different levels of dry-fractionated starch substitution tailor viscosity development and final gel strength. To characterise structural changes during heating, pasting behaviour was evaluated at 95 °C and 120 °C using a high-temperature Rapid Visco Analyser, while gel strength, temperature-ramp rheology, and thermal transitions were measured using a texture analyser, rheometer, and Differential Scanning Calorimetry. At 95 °C, all systems showed controlled pasting behaviour, with yellow pea exhibiting moderate viscosity development and clear recovery during cooling, mungbean generating the highest peak viscosity, and faba bean forming the strongest elastic network and gel structure. At 120 °C, yellow pea showed reduced stability, whereas faba bean and mungbean retained higher viscosity during heating. Starch addition improved the viscosity stability and gel strength across all proteins by limiting excessive aggregation and supporting network formation. These findings clarify how protein type and starch substitution affect high-temperature gelation, supporting the development of a heat-stable, clean-label plant-based gel system. Full article

(This article belongs to the Special Issue Gels: Diversity of Structures and Applications in Food Science)

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26 pages, 4053 KB

Open AccessArticle

Design and Characterization of Gold Nanorod Hyaluronic Acid Hydrogel Nanocomposites for NIR Photothermally Assisted Drug Delivery

by Alessandro Molinelli, Leonardo Bianchi, Elisa Lacroce, Zoe Giorgi, Laura Polito, Ada De Luigi, Francesca Lopriore, Francesco Briatico Vangosa, Paolo Bigini, Paola Saccomandi and Filippo Rossi

Gels 2026, 12(1), 88; https://doi.org/10.3390/gels12010088 - 19 Jan 2026

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Abstract

The combination of gold nanoparticles (AuNPs) with hydrogels has drawn significant interest in the design of smart materials as advanced platforms for biomedical applications. These systems endow light-responsiveness enabled by the AuNPs localized surface plasmon resonance (LSPR) phenomenon. In this study, we propose [...] Read more.

The combination of gold nanoparticles (AuNPs) with hydrogels has drawn significant interest in the design of smart materials as advanced platforms for biomedical applications. These systems endow light-responsiveness enabled by the AuNPs localized surface plasmon resonance (LSPR) phenomenon. In this study, we propose a nanocomposite hydrogel in which gold nanorods (AuNRs) are included in an agarose–carbomer–hyaluronic acid (AC-HA)-based hydrogel matrix to study the correlation between light irradiation, local temperature increase, and drug release for potential light-assisted drug delivery applications. The gel is obtained through a facile microwave-assisted polycondensation reaction, and its properties are investigated as a function of both the hyaluronic acid molecular weight and ratio. Afterwards, AuNRs are incorporated in the AC-HA formulation, before the sol–gel transition, to impart light-responsiveness and optical properties to the otherwise inert polymeric matrix. Particular attention is given to the evaluation of AuNRs/AC-HA light-induced heat generation and drug delivery performances under near-infrared (NIR) laser irradiation in vitro. Spatiotemporal thermal profiles and high-resolution thermal maps are registered using fiber Bragg grating (FBG) sensor arrays, enabling accurate probing of maximum internal temperature variations within the composite matrix. Lastly, using a high-steric-hindrance protein (BSA) as a drug mimetic, we demonstrate that moderate localized heating under short-time repeated NIR exposure enhances the release from the nanocomposite hydrogel. Full article

(This article belongs to the Special Issue Hydrogels for Tissue Repair: Innovations and Applications)

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17 pages, 2752 KB

Open AccessArticle

Evaluation of Chromium-Crosslinked AMPS-HPAM Copolymer Gels: Effects of Key Parameters on Gelation Time and Strength

by Maryam Sharifi Paroushi, Baojun Bai, Thomas P. Schuman, Yin Zhang and Mingzhen Wei

Gels 2026, 12(1), 87; https://doi.org/10.3390/gels12010087 - 19 Jan 2026

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Abstract

Controlling CO₂ channeling in heterogeneous reservoirs remains a major challenge for both enhanced oil recovery (EOR) and secure geological storage. AMPS-HPAM copolymers exhibit high-temperature resistance and brine tolerance compared with conventional HPAM gels, making them well suited for the harsh environments associated [...] Read more.

Controlling CO₂ channeling in heterogeneous reservoirs remains a major challenge for both enhanced oil recovery (EOR) and secure geological storage. AMPS-HPAM copolymers exhibit high-temperature resistance and brine tolerance compared with conventional HPAM gels, making them well suited for the harsh environments associated with CO₂ injection. Chromium-based crosslinkers (CrAc and CrCl₃) were investigated because sulfonic acid groups in AMPS can coordinate with trivalent chromium ions, enabling dual ionic crosslinking and the formation of a robust gel network. While organic crosslinked AMPS-HPAM gels have been widely studied, the behavior of chromium-crosslinked AMPS-containing systems, particularly their gelation kinetics under CO₂ exposure, remains less explored. This experimental study evaluates the gelation behavior and stability of chromium-crosslinked AMPS-HPAM gels by examining the effects of the polymer concentration, molecular weight, polymer–crosslinker ratio, temperature, pH, salinity, and dissolved CO₂. The results clarify the crosslinking behavior across a range of formulations and environmental conditions and establish criteria for designing robust gel systems. Gelation times can be controlled from 5 to 10 h, and the resulting gels maintained structural integrity under CO₂ exposure with less than 3.6% dehydration. Long-term thermal testing has shown that the gel remains stable after 10 months at 100 °C, with evaluation still ongoing. These results demonstrate that chromium-crosslinked AMPS-HPAM gels provide both durability and tunability for diverse subsurface conditions. Full article

(This article belongs to the Special Issue State-of-the Art Gel Research in USA)

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15 pages, 2150 KB

Open AccessArticle

Liquid Metal Particles–Graphene Core–Shell Structure Enabled Hydrogel-Based Triboelectric Nanogenerators

by Sangkeun Oh, Yoonsu Lee, Jungin Yang, Yejin Lee, Seoyeon Won, Sang Sub Han, Jung Han Kim and Taehwan Lim

Gels 2026, 12(1), 86; https://doi.org/10.3390/gels12010086 - 19 Jan 2026

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Abstract

The development of flexible and self-powered electronic systems requires triboelectric materials that combine high charge retention, mechanical compliance, and stable dielectric properties. Here, we report a redox reaction approach to prepare liquid metal particle-reduced graphene oxide (LMP@rGO) core–shell structures and introduce into a [...] Read more.

The development of flexible and self-powered electronic systems requires triboelectric materials that combine high charge retention, mechanical compliance, and stable dielectric properties. Here, we report a redox reaction approach to prepare liquid metal particle-reduced graphene oxide (LMP@rGO) core–shell structures and introduce into a poly(acrylic acid) (PAA) hydrogel to create a high-performance triboelectric layer. The spontaneous interfacial reaction between gallium oxide of LMP and graphene oxide produces a conformal rGO shell while simultaneously removing the native insulating oxide layer onto the LMP surface, resulting in enhanced colloidal stability and a controllable semiconductive bandgap of 2.7 (0.01 wt%), 2.9 (0.005 wt%) and 3.2 eV (0.001 wt%). Increasing the GO content promotes more complete core–shell formation, leading to higher zeta potentials, stronger interfacial polarization, and higher electrical performance. After embedding in PAA, the LMP@rGO structures form hydrogen-bonding networks with the hydrogel nature, improving both dielectric constant and charge retention while notably preserving soft mechanical compliance. The resulting LMP@rGO/PAA hydrogels show enhanced triboelectric output, with the 2.0 wt/vol% composite generating sufficient power to illuminate more than half of 504 series-connected LEDs. All the results demonstrate the potential of LMP@rGO hydrogel composites as promising triboelectric layer materials for next-generation wearable and self-powered electronic systems. Full article

(This article belongs to the Special Issue Recent Progress and Advances in Conductive or Smart Functional Polymer Gels)

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15 pages, 7553 KB

Open AccessArticle

Assessment of Antibiotic Sensitivity in Biofilms Using GelMA Hydrogel Microspheres

by Junchi Zhu, Wenqi Chen, Zhenzhi Shi, Yiming Liu, Lulu Shi and Jiafei Xi

Gels 2026, 12(1), 85; https://doi.org/10.3390/gels12010085 - 18 Jan 2026

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Abstract

Conventional antibiotic susceptibility testing (AST) primarily assesses planktonic bacteria. However, the three-dimensional architecture and barrier properties of biofilms mean that the minimum inhibitory concentration (MIC) for planktonic cells is typically far lower than the antibiotic exposure required for biofilm eradication. In this study, [...] Read more.

Conventional antibiotic susceptibility testing (AST) primarily assesses planktonic bacteria. However, the three-dimensional architecture and barrier properties of biofilms mean that the minimum inhibitory concentration (MIC) for planktonic cells is typically far lower than the antibiotic exposure required for biofilm eradication. In this study, gelatin methacryloyl (GelMA) microspheres were used to create a three-dimensional biofilm microenvironment for the quantitative evaluation of biofilm tolerance. Escherichia coli K-12 MG1655 was immersed in GelMA microspheres and subjected to a series of antibiotic concentration gradients. Bacterial viability was inferred from time-dependent changes in microsphere diameter. The results demonstrated substantial tolerance of the resulting biofilms to ampicillin, ciprofloxacin, and ceftriaxone, with biofilm antibiotic tolerance values exceeding 200 μg/mL, 10–50 μg/mL, and 20–50 μg/mL, respectively. Relative to planktonic MICs, these tolerance levels are elevated by one to two orders of magnitude and surpass the standard clinical breakpoint thresholds. This methodology includes a high-throughput platform, involving only several hundred microspheres and achieving completion within 24 h, thereby offering a useful platform for investigating biofilm resistance mechanisms and guiding antibiotic treatment strategies. Full article

(This article belongs to the Section Gel Chemistry and Physics)

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22 pages, 5030 KB

Open AccessArticle

Features of Uranium Recovery from Complex Aqueous Solutions Using Composite Sorbents Based on Se-Derivatives of Amidoximes

by Eduard A. Tokar’, Anna I. Matskevich, Konstantin V. Maslov, Veronika A. Prokudina, Alena N. Popova and Dmitry K. Patrushev

Gels 2026, 12(1), 84; https://doi.org/10.3390/gels12010084 - 18 Jan 2026

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Abstract

The article presents a comprehensive comparative performance evaluation and validation of composite adsorbents based on the Se-derivative of 4-amino-N′-hydroxy-1,2,5-oxadiazole-3-carboximidamide for U (VI) recovery from complex multicomponent aqueous media. Our results indicate the composite materials to be comparable to, and in some cases to [...] Read more.

The article presents a comprehensive comparative performance evaluation and validation of composite adsorbents based on the Se-derivative of 4-amino-N′-hydroxy-1,2,5-oxadiazole-3-carboximidamide for U (VI) recovery from complex multicomponent aqueous media. Our results indicate the composite materials to be comparable to, and in some cases to surpass, existing adsorbents in recovery efficiency. Under static sorption conditions for trace U (VI) from real multicomponent solutions (tap, river, and sea water), the sorption efficiency reached 80–98%, while the distribution coefficients ranged from 10⁴ to 10⁶ cm³ g⁻¹. The sorption-selectivity properties of the materials were evaluated in the presence of competing ions (EDTA and oxalate ions), which possess a high chelating capacity and a strong tendency to form complexes with uranium. The dependence of sorption efficiency on the concentration of these ions and the solution pH was investigated. The possibility of reusing the materials over multiple sorption-desorption cycles was assessed. An optimal regenerating eluent agent was identified (NaHCO₃/NH₄NO₃), providing a desorption efficiency of >95% without degrading the material’s sorption properties over repeated cycles. Using a combination of physicochemical methods, including sorption techniques, the mechanism of uranium sorption and its dependence on the material structure were determined. The efficiency of uranium recovery from multicomponent natural waters was also investigated under dynamic conditions over repeated sorption-desorption cycles. The results demonstrate through comparative analysis that the developed composites exhibit a high sorption capacity and possess a high practical potential for the concentration and recovery of uranium from high-salinity solutions with complex composition. Full article

(This article belongs to the Section Gel Analysis and Characterization)

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17 pages, 3466 KB

Open AccessArticle

Regulation of Microstructure and Properties of Konjac Glucomannan Gels via Ethanol Under Low-Alkali Conditions

by Meiqiu Xu, Hongtao Du, Solairaj Dhanasekaran, Yin Jia, Yange Ren, Hong Chen and Wei Xu

Gels 2026, 12(1), 83; https://doi.org/10.3390/gels12010083 - 17 Jan 2026

Viewed by 198

Abstract

Despite their potential, alkali-treated konjac glucomannan (KGM) gels are limited by excessive brittleness and a lack of eco-friendly synthesis methods, creating an urgent need for more durable and ‘green’ alternatives. In this study, highly stable KGM gels were constructed under low-alkali conditions by [...] Read more.

Despite their potential, alkali-treated konjac glucomannan (KGM) gels are limited by excessive brittleness and a lack of eco-friendly synthesis methods, creating an urgent need for more durable and ‘green’ alternatives. In this study, highly stable KGM gels were constructed under low-alkali conditions by adjusting the ethanol content. The results showed that intermolecular hydrogen bonding and hydrophobic interactions were enhanced with increasing ethanol concentration (0–20% v/v) under low-alkaline conditions. The physicochemical properties of KGM gels showed dynamic improvement, with denser micro-network morphology and simultaneous enhancement of thermal stability. However, the addition of a high ethanol concentration (20% v/v) tended to trigger local aggregation, disrupting the gel network structure. At an ethanol addition of 15%, the hydrogen bonding and hydrophobic interactions of KGM gels reached an optimal equilibrium, exhibiting the most compact gel network and excellent resistance to deformation. This study reveals the regulation of the microstructure and macroscopic properties of KGM gels by ethanol, which provides theoretical support for the construction of high-performance KGM gels under low-alkali conditions. Full article

(This article belongs to the Special Issue Application of Composite Gels in Food Processing and Engineering)

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22 pages, 35472 KB

Open AccessArticle

Development and Characterization of Clindamycin-Loaded Dextran Hydrogel for Controlled Drug Release and Pathogen Inhibition

by Iqra Jawad, Asma Rehman, Mariam Hamdan, Kalsoom Akhtar, Shazia Khaliq, Munir Ahmad Anwar and Nayla Munawar

Gels 2026, 12(1), 82; https://doi.org/10.3390/gels12010082 - 17 Jan 2026

Viewed by 324

Abstract

The naturally occurring, biocompatible and biodegradable biopolymer dextran is a versatile material for the formulation of hydrogels with desirable properties for use in medicine, drug delivery, and tissue engineering applications. The distinctive structural and physicochemical characteristics, such as polymeric nature, gelling ability and [...] Read more.

The naturally occurring, biocompatible and biodegradable biopolymer dextran is a versatile material for the formulation of hydrogels with desirable properties for use in medicine, drug delivery, and tissue engineering applications. The distinctive structural and physicochemical characteristics, such as polymeric nature, gelling ability and excellent swelling properties, present it as an excellent biomaterial for drug delivery. This study explores the synthesis and characterization of dextran hydrogel for the encapsulation of clindamycin as an innovative approach for controlled drug delivery. The dextran hydrogel was synthesized through a simple and cost-effective method, and its swelling behavior, temperature and pH dependence, and surface morphology were investigated. The maximum equilibrium swelling ratio (73 ± 1%) of the hydrogel was observed in water at 25 °C within 120 min, and the hydrogel was found to be pH- and temperature-dependent for more precise and targeted drug delivery. Moreover, the dextran hydrogel was found to retain water for up to 18 h and remain stable for 8 days. The presence of a roughened surface with large openings/pores on the surface illustrated the high swelling capability of the synthesized hydrogel. In addition, the dextran hydrogel loaded with clindamycin demonstrated high drug loading capacity (70 ± 2%), rapid (65 ± 2%) in vitro drug release potential and pathogen-inhibitory activity against Staphylococcus gallinarium and Bacillus subtilis. Full article

(This article belongs to the Section Gel Analysis and Characterization)

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15 pages, 1991 KB

Open AccessReview

Injectable Scaffolds for Adipose Tissue Reconstruction

by Valeria Pruzzo, Francesca Bonomi, Ettore Limido, Andrea Weinzierl, Yves Harder and Matthias W. Laschke

Gels 2026, 12(1), 81; https://doi.org/10.3390/gels12010081 - 17 Jan 2026

Viewed by 405

Abstract

Autologous fat grafting is the main surgical technique for soft tissue reconstruction. However, its clinical use with more extended volumes is limited by repeated procedures due to the little possibility of banking tissue, donor-site morbidity and unpredictable graft resorption rates. To overcome these [...] Read more.

Autologous fat grafting is the main surgical technique for soft tissue reconstruction. However, its clinical use with more extended volumes is limited by repeated procedures due to the little possibility of banking tissue, donor-site morbidity and unpredictable graft resorption rates. To overcome these problems, adipose tissue engineering has focused on developing injectable scaffolds. Most of them are hydrogels that closely mimic the biological, structural and mechanical characteristics of native adipose tissue. This review provides an overview of current injectable scaffolds designed to restore soft tissue volume defects, emphasizing their translational potential and future directions. Natural injectable scaffolds exhibit excellent biocompatibility but degrade rapidly and lack mechanical strength. Synthetic injectable scaffolds provide tunable elasticity and degradation rates but require biofunctionalization to support cell adhesion and tissue integration. Adipose extracellular matrix-derived injectable scaffolds are fabricated by decellularization of adipose tissue. Accordingly, they combine bio-mimetic structure with intrinsic biological cues that stimulate host-driven adipogenesis and angiogenesis, thus representing a translatable “off-the-shelf” alternative to autologous fat grafting. However, despite this broad spectrum of available injectable scaffolds, the establishment of clinically reliable soft tissue substitutes capable of supporting large-volume and long-lasting soft tissue reconstruction still remains an open challenge. Full article

(This article belongs to the Special Issue Hydrogels for Tissue Repair: Innovations and Applications)

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31 pages, 5373 KB

Open AccessReview

Emerging Gel Technologies for Atherosclerosis Research and Intervention

by Sen Tong, Jiaxin Chen, Yan Li and Wei Zhao

Gels 2026, 12(1), 80; https://doi.org/10.3390/gels12010080 - 16 Jan 2026

Viewed by 370

Abstract

Atherosclerosis remains a leading cause of cardiovascular mortality despite advances in pharmacological and interventional therapies. Current treatment approaches face limitations including systemic side effects, inadequate local drug delivery, and restenosis following vascular interventions. Gel-based technologies offer unique advantages through tunable mechanical properties, controlled [...] Read more.

Atherosclerosis remains a leading cause of cardiovascular mortality despite advances in pharmacological and interventional therapies. Current treatment approaches face limitations including systemic side effects, inadequate local drug delivery, and restenosis following vascular interventions. Gel-based technologies offer unique advantages through tunable mechanical properties, controlled degradation kinetics, high drug-loading capacity, and potential for stimuli-responsive therapeutic release. This review examines gel platforms across multiple scales and applications in atherosclerosis research and intervention. First, gel-based in vitro models are discussed. These include hydrogel matrices simulating plaque microenvironments, three-dimensional cellular culture platforms, and microfluidic organ-on-chip devices. These devices incorporate physiological flow to investigate disease mechanisms under controlled conditions. Second, therapeutic strategies are addressed through macroscopic gels for localized treatment. These encompass natural polymer-based, synthetic polymer-based, and composite formulations. Applications include stent coatings, adventitial injections, and catheter-delivered depots. Natural polymers often possess intrinsic biological activities including anti-inflammatory and immunomodulatory properties that may contribute to therapeutic effects. Third, nano- and microgels for systemic delivery are examined. These include polymer-based nanogels with stimuli-responsive drug release responding to oxidative stress, pH changes, and enzymatic activity characteristic of atherosclerotic lesions. Inorganic–organic composite nanogels incorporating paramagnetic contrast agents enable theranostic applications by combining therapy with imaging-guided treatment monitoring. Current challenges include manufacturing consistency, mechanical stability under physiological flow, long-term safety assessment, and regulatory pathway definition. Future opportunities are discussed in multi-functional integration, artificial intelligence-guided design, personalized formulations, and biomimetic approaches. Gel technologies demonstrate substantial potential to advance atherosclerosis management through improved spatial and temporal control over therapeutic interventions. Full article

(This article belongs to the Special Issue Nanogels and Microgels: Fundamental Studies, Applications, and Emerging Trends)

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30 pages, 13241 KB

Open AccessArticle

Nanosilica Gel-Stabilized Phase-Change Materials Based on Epoxy Resin and Wood’s Metal

by Svetlana O. Ilyina, Irina Y. Gorbunova, Vyacheslav V. Shutov, Michael L. Kerber and Sergey O. Ilyin

Gels 2026, 12(1), 79; https://doi.org/10.3390/gels12010079 - 16 Jan 2026

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Abstract

The emulsification of a molten fusible metal alloy in a liquid epoxy matrix with its subsequent curing is a novel way to create a highly concentrated phase-change material. However, numerous challenges have arisen. The high interfacial tension between the molten metal and epoxy [...] Read more.

The emulsification of a molten fusible metal alloy in a liquid epoxy matrix with its subsequent curing is a novel way to create a highly concentrated phase-change material. However, numerous challenges have arisen. The high interfacial tension between the molten metal and epoxy resin and the difference in their viscosities hinder the stretching and breaking of metal droplets during stirring. Further, the high density of metal droplets and lack of suitable surfactants lead to their rapid coalescence and sedimentation in the non-cross-linked resin. Finally, the high differences in the thermal expansion coefficients of the metal alloy and cross-linked epoxy polymer may cause cracking of the resulting phase-change material. This work overcomes the above problems by using nanosilica-induced physical gelation to thicken the epoxy medium containing Wood’s metal, stabilize their interfacial boundary, and immobilize the molten metal droplets through the creation of a gel-like network with a yield stress. In turn, the yield stress and the subsequent low-temperature curing with diethylenetriamine prevent delamination and cracking, while the transformation of the epoxy resin as a physical gel into a cross-linked polymer gel ensures form stability. The stabilization mechanism is shown to combine Pickering-like interfacial anchoring of hydrophilic silica at the metal/epoxy boundary with bulk gelation of the epoxy phase, enabling high metal loadings. As a result, epoxy shape-stable phase-change materials containing up to 80 wt% of Wood’s metal were produced. Wood’s metal forms fine dispersed droplets in epoxy medium with an average size of 2–5 µm, which can store thermal energy with an efficiency of up to 120.8 J/cm³. Wood’s metal plasticizes the epoxy matrix and decreases its glass transition temperature because of interactions with the epoxy resin and its hardener. However, the reinforcing effect of the metal particles compensates for this adverse effect, increasing Young’s modulus of the cured phase-change system up to 825 MPa. These form-stable, high-energy-density composites are promising for thermal energy storage in building envelopes, radiation-protective shielding, or industrial heat management systems where leakage-free operation and mechanical integrity are critical. Full article

(This article belongs to the Special Issue Energy Storage and Conductive Gel Polymers)

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22 pages, 6094 KB

Open AccessArticle

Molecularly Engineered Aza-Crown Ether Functionalized Sodium Alginate Aerogels for Highly Selective and Sustainable Cu²⁺ Removal

by Teng Long, Ayoub El Idrissi, Lin Fu, Yufan Liu, Banlian Ruan, Minghong Ma, Zhongxun Li and Lingbin Lu

Gels 2026, 12(1), 78; https://doi.org/10.3390/gels12010078 - 16 Jan 2026

Viewed by 201

Abstract

Developing sustainable and molecularly selective adsorbents for heavy-metal removal remains a critical challenge in water purification. Herein, we report a green molecular-engineering approach for fabricating aza-crown ether functionalized sodium alginate aerogels (ACSA) capable of highly selective Cu²⁺ capture. The aerogels were synthesized [...] Read more.

Developing sustainable and molecularly selective adsorbents for heavy-metal removal remains a critical challenge in water purification. Herein, we report a green molecular-engineering approach for fabricating aza-crown ether functionalized sodium alginate aerogels (ACSA) capable of highly selective Cu²⁺ capture. The aerogels were synthesized via saccharide-ring oxidation, Cu²⁺-templated self-assembly, and reductive amination, enabling the covalent integration of aza-crown ether motifs within a hierarchically porous biopolymer matrix. Structural analyses (FTIR, ¹³C NMR, XPS, SEM, TGA) confirmed the in situ formation of macrocyclic N/O coordination sites. Owing to their interconnected porosity and chemically stable framework, ACSA exhibited rapid sorption kinetics following a pseudo-second-order model (R² = 0.999) and a Langmuir maximum adsorption capacity of 150.82 mg·g⁻¹. The material displayed remarkable Cu²⁺ selectivity over Zn²⁺, Cd²⁺, and Ni²⁺, arising from the precise alignment between Cu²⁺ ionic radius (0.73 Å) and crown-cavity dimensions, synergistic N/O chelation, and Jahn-Teller stabilization. Over four regeneration cycles, ACSA retained more than 80% of its original adsorption capacity, confirming excellent durability and reusability. This saccharide-ring modification strategy eliminates crown-ether leaching and weak anchoring, offering a scalable and environmentally benign route to bio-based adsorbents that combine molecular recognition with structural stability for efficient Cu²⁺ remediation and beyond. Full article

(This article belongs to the Section Gel Processing and Engineering)

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20 pages, 5073 KB

Open AccessArticle

Textural Properties of Carbopol^® Gel with Curcumin and Curcumin–HPβCD Inclusion Complex and Biological Activities

by Maja Urošević, Vesna Nikolić, Vesna Savić, Tatjana Mihajilov-Krstev, Ivana Gajić, Ana Dinić, Milica Martinović and Ljubiša Nikolić

Gels 2026, 12(1), 77; https://doi.org/10.3390/gels12010077 - 16 Jan 2026

Viewed by 157

Abstract

The aim of this study was to prepare curcumin/2-hydroxypropyl-β-cyclodextrin (HPβCD) inclusion complex, evaluate the antioxidant and antimicrobial activities of curcumin and curcumin in inclusion complex, as well as to examine the effect of curcumin and curcumin inclusion complex on the textural properties of [...] Read more.

The aim of this study was to prepare curcumin/2-hydroxypropyl-β-cyclodextrin (HPβCD) inclusion complex, evaluate the antioxidant and antimicrobial activities of curcumin and curcumin in inclusion complex, as well as to examine the effect of curcumin and curcumin inclusion complex on the textural properties of Carbopol^® gel mixture. Curcumin/2-hydroxypropyl-β-cyclodextrin inclusion complex was prepared using the co-precipitation method in a molar ratio of 1:1. The antioxidant activity of curcumin and curcumin in inclusion complex was determined using DPPH, ABTS, and FRAP methods. The micro-dilution method was used to examine in vitro the antimicrobial activity of curcumin and curcumin in inclusion complex. The textural, rheological, and morphological properties of the samples (Gel 1- Carbopol^® gel; Gel 2- Carbopol^® gel with dispersed curcumin inclusion complex; Gel 3- Carbopol^® gel with dispersed curcumin) were examined. The textural properties were evaluated using a texturometer CT3 Texture Analyzer by means of a Texture Profile Analysis (TPA) test. The results showed that curcumin in inclusion complex had higher antioxidant and antimicrobial activity. The SEM confirms the presence of curcumin and inclusion complex in Carbopol^® gel. The rheological analysis confirmed that the structural integrity of Carbopol^® gel was preserved. The highest swelling degree is achieved by Gel 3 formulation. The in vitro release of curcumin from Gel 2 and Gel 3 occurs at the rates of 0.414 µg/h·g_gel and 0.376 µg/h·g_gel, respectively. The textural analysis showed that adding curcumin or its inclusion complex did not significantly change the properties of Carbopol^® gel, indicating potential for topical use. Full article

(This article belongs to the Section Gel Applications)

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16 pages, 2811 KB

Open AccessArticle

Construction of Flexible Kaolin/Chitin Composite Aerogels and Their Properties

by Meng He, Yujia Huang, Zhicheng Cui, Ziyue Cheng, Weiwei Cao, Gan Wang, Wei Yao and Mengna Feng

Gels 2026, 12(1), 76; https://doi.org/10.3390/gels12010076 - 15 Jan 2026

Cited by 1 | Viewed by 203

Abstract

In this work, kaolin/chitin (K/Ch) composite aerogels with different mass ratios were successfully fabricated via a freeze–drying approach. The influence of kaolin content on the microstructure, properties and hemostatic performance of the composite aerogels was systematically investigated. The results demonstrated that the incorporation [...] Read more.

In this work, kaolin/chitin (K/Ch) composite aerogels with different mass ratios were successfully fabricated via a freeze–drying approach. The influence of kaolin content on the microstructure, properties and hemostatic performance of the composite aerogels was systematically investigated. The results demonstrated that the incorporation of kaolin endowed the chitin-based aerogels with tunable porous structures, excellent water absorption capacity (up to 4282% for K_0.25/Ch₂), and enhanced water retention (73.7% for K₂/Ch₂ at 60 min). Moreover, the K/Ch composite aerogels exhibited good biodegradability, no cytotoxicity (cell viability > 91.9%), and no hemolysis (hemolysis rate < 1.5% at all test concentrations). In vitro hemostatic evaluations revealed that the composite aerogels exhibited rapid blood coagulation (blood clotting time of 16 s for K₂/Ch₂) with a blood coagulation index (BCI) as low as 0.5%, which was attributed to the synergistic effect of the physical adsorption of chitin and the coagulation cascade activation by kaolin. These findings indicated that the K/Ch composite aerogels could be used as novel natural hemostatic materials for potential effective and rapid hemostasis. Full article

(This article belongs to the Special Issue Recent Advances in Aerogels (2nd Edition))

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24 pages, 5039 KB

Open AccessArticle

Impact of Gel-Derived Morphology-Controlled UiO-66/Cellulose Nanofiber Composite Separators on the Performance of Aqueous Zinc-Ion Batteries

by Tian Zhao, Jiangrong Yu, Shilin Peng, Yan Wu, Tianhang Wang, Zhuoheng Li, Ling Shen, Christoph Janiak and Yi Chen

Gels 2026, 12(1), 75; https://doi.org/10.3390/gels12010075 - 15 Jan 2026

Viewed by 244

Abstract

Zinc dendrite growth and side reactions remain critical challenges hindering the advancement of aqueous zinc-ion batteries (AZIBs). This study proposes a gel-based strategy for designing high-performance separators by regulating the crystal morphology of the metal–organic framework UiO-66 within a cellulose nanofiber (CNF) gel [...] Read more.

Zinc dendrite growth and side reactions remain critical challenges hindering the advancement of aqueous zinc-ion batteries (AZIBs). This study proposes a gel-based strategy for designing high-performance separators by regulating the crystal morphology of the metal–organic framework UiO-66 within a cellulose nanofiber (CNF) gel matrix. The resulting gel-derived separators exhibit distinctive structural and interfacial properties that significantly enhance battery performance. Compared with hierarchical porous structures (H-UiO-66), the octahedral morphology (O-UiO-66) disperses more uniformly in the CNF gel network, forming well-defined ion transport channels through its integrated gel architecture. The fabricated O-UiO-66/CNF gel separator demonstrates exceptional hydrophilicity (contact angle 21°), high porosity (73.2%), and significantly improved zinc ion migration number (0.72). Electrochemical tests reveal that this gel-based separator effectively guides uniform zinc deposition while suppressing dendrite growth. Zn/Zn symmetric cells using the O-UiO-66/CNF gel separator achieve a cycle life exceeding 800 h at 1 mA cm⁻². The Zn/MnO₂ full cell maintains 98.1% capacity retention after 100 cycles at 1 A g⁻¹. This work establishes a structure–performance relationship between MOF morphology and gel separator properties, providing new insights for designing advanced gel-based materials for AZIBs. Full article

(This article belongs to the Special Issue Gel-Based Materials for Energy Storage)

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28 pages, 8828 KB

Open AccessArticle

Oil-Water Biphasic Metal-Organic Supramolecular Gel for Lost Circulation Control: Formulation Optimization, Gelation Mechanism, and Plugging Performance

by Qingwang Li, Songlei Li, Ye Zhang, Chaogang Chen, Xiaochuan Wu, Menglai Li, Shubiao Pan and Junfei Peng

Gels 2026, 12(1), 74; https://doi.org/10.3390/gels12010074 - 15 Jan 2026

Viewed by 202

Abstract

Lost circulation in oil-based drilling fluids (OBDFs) remains difficult to mitigate because particulate lost circulation materials depend on bridging/packing and gel systems for aqueous media often lack OBDF compatibility and controllable in situ sealing. A dual-precursor oil–water biphasic metal–organic supramolecular gel enables rapid [...] Read more.

Lost circulation in oil-based drilling fluids (OBDFs) remains difficult to mitigate because particulate lost circulation materials depend on bridging/packing and gel systems for aqueous media often lack OBDF compatibility and controllable in situ sealing. A dual-precursor oil–water biphasic metal–organic supramolecular gel enables rapid in situ sealing in OBDF loss zones. The optimized formulation uses an oil-phase to aqueous gelling-solution volume ratio of 10:3, with 2.0 wt% Span 85, 12.5 wt% TXP-4, and 5.0 wt% NaAlO₂. Apparent-viscosity measurements and ATR–FTIR analysis were used to evaluate the effects of temperature, time, pH, and shear on MOSG gelation. Furthermore, the structural characteristics and performances of MOSGs were systematically investigated by combining microstructural characterization, thermogravimetric analysis, rheological tests, simulated fracture-plugging experiments, and anti-shear evaluations. The results indicate that elevated temperatures (30–70 °C) and mildly alkaline conditions in the aqueous gelling solution (pH ≈ 8.10–8.30) promote P–O–Al coordination and strengthen hydrogen bonding, thereby facilitating the formation of a three-dimensional network. In contrast, strong shear disrupts the nascent network and delays gelation. The optimized MOSGs rapidly exhibit pronounced viscoelasticity and thermal resistance (~193 °C); under high shear (380 rpm), the viscosity retention exceeds 60% and the viscosity recovery exceeds 70%. In plugging tests, MOSG forms a dense sealing layer, achieving a pressure-bearing gradient of 2.27 MPa/m in simulated permeable formations and markedly improving the fracture pressure-bearing capacity in simulated fractured formations. Full article

(This article belongs to the Topic Advanced Technology for Oil and Nature Gas Exploration)

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15 pages, 2079 KB

Open AccessArticle

Comparative Study on the In Vitro Gastrointestinal Digestion of Oil Body Suspension from Different Parts of Idesia polycarpa Maxim

by Silu Cheng, Yongchen Liu, Mingzhang Zhao, Shanshan Qian, Hongxia Feng, Yunhe Chang, Juncai Hou and Cong Xu

Gels 2026, 12(1), 73; https://doi.org/10.3390/gels12010073 - 14 Jan 2026

Viewed by 175

Abstract

This study provides the first comparative analysis of the physicochemical and functional properties of oil body suspensions derived from different parts—entire fruit (EOB), peel (POB), and seed (SOB)—of Idesia polycarpa Maxim (IPM) during in vitro simulated gastrointestinal digestion. Results demonstrated that the properties [...] Read more.

This study provides the first comparative analysis of the physicochemical and functional properties of oil body suspensions derived from different parts—entire fruit (EOB), peel (POB), and seed (SOB)—of Idesia polycarpa Maxim (IPM) during in vitro simulated gastrointestinal digestion. Results demonstrated that the properties of the different suspensions exhibited significant difference during digestion stages. The average particle size of all suspensions decreased, with the most significant reduction observed in POB (91.50%), which was attributable to its lower interfacial protein content and inferior stability. The absolute ζ-potential decreased in the model of gastric digestion (MGD) due to interface disruption but increased in the model of intestinal digestion (MID) following the adsorption of bile salts. Throughout the simulated digestion process, the protein hydrolysis degree, free fatty acid (FFA) release rate, reducing power, and inhibition rates against α-amylase and α-glucosidase all increased, concurrently with a decrease in DPPH radical scavenging activity. Notably, the POB suspension exhibited the highest extent of lipid digestion, with the highest cumulative FFA release rate (27.83%). In contrast, the SOB suspension showed the most significant enhancement in total reducing power (increased by 199.32% after intestinal digestion) and the highest α-glucosidase inhibitory activity. These findings clarify that the part source is a critical factor influencing the digestive properties and functional activities of IPM oil bodies, providing a theoretical foundation for the targeted application in functional foods. Full article

(This article belongs to the Special Issue Properties and Structure of Plant-Based Emulsion Gels)

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25 pages, 4142 KB

Open AccessArticle

Puerarin-Loaded Proniosomal Gel: Formulation, Characterization, In Vitro Antimelanoma Cytotoxic Potential, and In Ovo Irritation Assessment

by Sergio Liga, Andra Tămaș, Raluca Vodă, Gerlinde Rusu, Ioan Bîtcan, Vlad Socoliuc, Raluca Pop, Diana Haj Ali, Iasmina-Alexandra Predescu, Cristina Adriana Dehelean and Francisc Péter

Gels 2026, 12(1), 72; https://doi.org/10.3390/gels12010072 - 13 Jan 2026

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Abstract

Puerarin is a naturally occurring isoflavone with reported anticancer activity, yet its topical translation is constrained by limited stability and suboptimal dermal delivery. A Puerarin-loaded proniosomal gel was developed as a potential dermal delivery platform, and we performed an initial assessment of its [...] Read more.

Puerarin is a naturally occurring isoflavone with reported anticancer activity, yet its topical translation is constrained by limited stability and suboptimal dermal delivery. A Puerarin-loaded proniosomal gel was developed as a potential dermal delivery platform, and we performed an initial assessment of its antimelanoma activity and safety. The gel was produced by coacervation–phase separation using Span 60, Tween 80, phosphatidylcholine, and cholesterol. Physicochemical characterization included pH, entrapment efficiency, rheology, FTIR, DSC, and vesicle properties (DLS, PDI, ζ-potential). In silico geometry optimization and docking were carried out for melanoma-associated targets (MITF and DNMT3B). Biological effects were investigated in vitro on A375 melanoma cells using MTT, morphological analysis, and nuclear/mitochondrial staining, while irritation potential was evaluated in ovo by HET-CAM. The optimized formulation exhibited a skin-compatible pH and an entrapment efficiency of 62 ± 0.26%. DLS indicated a multimodal population, with a major number-weighted vesicle population in the 100–200 nm range, and a ζ-potential of −34.9 ± 0.14 mV. FTIR and DSC supported component incorporation without evidence of chemical incompatibility. The gel showed non-Newtonian, pseudoplastic, thixotropic flow, which is advantageous for topical use. Docking predicted meaningful affinities of Puerarin toward MITF and DNMT3B. The formulation reduced A375 viability in a dose-dependent manner (to 44.66% at 200 µg/mL) and, at higher concentrations, produced nuclear condensation and disruption of the mitochondrial network. HET-CAM classified the gel as non-irritant. The Puerarin-loaded proniosomal gel represents a promising topical platform with preliminary in vitro antimelanoma cytotoxic potential, warranting additional studies to validate skin delivery, efficacy, and safety. Full article

(This article belongs to the Special Issue Natural Bioactive Compounds and Gels)

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27 pages, 980 KB

Open AccessReview

Rational Design of Mechanically Optimized Hydrogels for Bone Tissue Engineering: A Review

by Shengao Qin, Han Yuan, Zhaochen Shan, Jiaqi Wang and Wen Pan

Gels 2026, 12(1), 71; https://doi.org/10.3390/gels12010071 - 13 Jan 2026

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Abstract

Bone tissue engineering, as an important branch of regenerative medicine, integrates multidisciplinary knowledge from cell biology, materials science, and biomechanics, aiming to develop novel biomaterials and technologies for functional repair and regeneration of bone tissue. Hydrogels are among the most commonly used scaffold [...] Read more.

Bone tissue engineering, as an important branch of regenerative medicine, integrates multidisciplinary knowledge from cell biology, materials science, and biomechanics, aiming to develop novel biomaterials and technologies for functional repair and regeneration of bone tissue. Hydrogels are among the most commonly used scaffold materials; however, conventional hydrogels exhibit significant limitations in physical properties such as strength, tensile strength, toughness, and fatigue resistance, which severely restrict their application in load-bearing bone defect repair. As a result, the development of high-strength hydrogels has become a research hotspot in the field of bone tissue engineering. This paper systematically reviews the latest research progress in this area: First, it delves into the physicochemical characteristics of high-strength hydrogels at the molecular level, focusing on core features such as their crosslinking network structure, dynamic bonding mechanisms, and energy dissipation principles. Next, it categorically summarizes novel high-strength hydrogel systems and different types of biomimetic hydrogels developed based on various reinforcement strategies. Furthermore, it provides a detailed evaluation of the application effects of these advanced materials in specific anatomical sites, including cranial reconstruction, femoral repair, alveolar bone regeneration, and articular cartilage repair. This review aims to provide systematic theoretical guidance and technical references for the basic research and clinical translation of high-strength hydrogels in bone tissue engineering, promoting the effective translation of this field from laboratory research to clinical application. Full article

(This article belongs to the Special Issue Hydrogel-Based Scaffolds with a Focus on Medical Use (3rd Edition))

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18 pages, 2198 KB

Open AccessArticle

A 3D Alginate–Gelatin Co-Culture Model to Study Epithelial–Stromal Interactions in the Gut

by Paraskevi Tselekouni, Mansoureh Mohseni-Garakani, Steve Papa, Seong Yeon Kim, Rita Kohen Avramoglu, Michael R. Wertheimer, Abdellah Ajji, Peter L. Lakatos and Derek H. Rosenzweig

Gels 2026, 12(1), 70; https://doi.org/10.3390/gels12010070 - 13 Jan 2026

Viewed by 469

Abstract

Inflammatory bowel disease (IBD) arises from chronic dysregulation at the epithelial–stromal interface, creating a need for in vitro systems that better capture these interactions. In this study, we developed a 3D co-culture platform in which HT-29 intestinal epithelial cells and IMR-90 fibroblasts are [...] Read more.

Inflammatory bowel disease (IBD) arises from chronic dysregulation at the epithelial–stromal interface, creating a need for in vitro systems that better capture these interactions. In this study, we developed a 3D co-culture platform in which HT-29 intestinal epithelial cells and IMR-90 fibroblasts are embedded within an alginate–gelatin hydrogel, alongside a complementary interface model using a plasma-treated electrospun mesh to spatially compartmentalize stromal and epithelial layers. We first assessed metabolic activity, viability, and proliferation across several epithelial-to-fibroblast ratios and identified 1:0.5 as the most supportive of epithelial expansion. The A1G7 hydrogel maintained high viability (>92%) and sustained growth in all mono- and co-cultures. To evaluate inflammatory competence, models were stimulated with lipopolysaccharide (LPS), administered either within the hydrogel or through the culture medium. LPS exposure increased TNF-α and IL-1β secretion in both configurations, with the magnitude of the response depending on the delivery route. Treatment with dexamethasone consistently reduced cytokine levels, confirming the model’s suitability for pharmacological testing. Together, these results demonstrate that the alginate–gelatin system provides a reproducible epithelial–stromal platform with quantifiable inflammatory readouts, offering a practical foundation for mechanistic studies and early-stage screening of anti-inflammatory therapeutics in IBD. Full article

(This article belongs to the Special Issue Hydrogels for the Regeneration of Joints of the Musculoskeletal System in Orthopedics (2nd Edition))

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17 pages, 5690 KB

Open AccessReview

Conductive Hydrogels in Biomedical Engineering: Recent Advances and a Comprehensive Review

by Chenyu Shen, Ying Wang, Peng Yuan, Jinhuan Wei, Jingyin Bao and Zhangkang Li

Gels 2026, 12(1), 69; https://doi.org/10.3390/gels12010069 - 13 Jan 2026

Viewed by 355

Abstract

Conductive hydrogels have gained considerable interest in the biomedical field because they provide a soft, hydrated, and electrically active microenvironment that closely resembles native tissue. Their unique combination of electrical conductivity and biocompatibility enables monitoring and modulation of biological activities. With the rapid [...] Read more.

Conductive hydrogels have gained considerable interest in the biomedical field because they provide a soft, hydrated, and electrically active microenvironment that closely resembles native tissue. Their unique combination of electrical conductivity and biocompatibility enables monitoring and modulation of biological activities. With the rapid development of conductive hydrogel technologies in recent years, a comprehensive overview is needed to clarify their biological functions and the latest biomedical applications. This review first summarizes the fundamental design strategies, fabrication methods, and conductive mechanisms of conductive hydrogels. We then highlight their applications in wearable device, implanted bioelectronics, wound healing, neural regeneration and cell regulation, accompanied by discussions of the underlying biological and electroactive mechanisms. Potential challenges and future directions, including strategies to optimize fabrication methods, balance key material properties, and tailor conductive hydrogels for diverse biomedical applications, are also highlighted. Finally, we discuss the existing limitations and future perspectives of the biomedical applications of conductive hydrogels. We hope that this article may provide some useful insights to support their further development and potential biomedical applications. Full article

(This article belongs to the Special Issue Research on the Applications of Conductive Hydrogels)

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23 pages, 5917 KB

Open AccessArticle

Preparation of CO₂-Adsorbing Fire-Extinguishing Gel and Study on Inhibition of Coal Spontaneous Combustion

by Jianguo Wang, Zhenzhen Zhang and Conghui Li

Gels 2026, 12(1), 68; https://doi.org/10.3390/gels12010068 - 12 Jan 2026

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Abstract

Spontaneous coal combustion accounts for more than 90% of mine fires, and at the same time, the ‘dual carbon’ strategy requires fire prevention and extinguishing materials to have both low-carbon and environmentally friendly functions. To meet on-site application needs, a composite gel with [...] Read more.

Spontaneous coal combustion accounts for more than 90% of mine fires, and at the same time, the ‘dual carbon’ strategy requires fire prevention and extinguishing materials to have both low-carbon and environmentally friendly functions. To meet on-site application needs, a composite gel with fast injection, flame retardant, and CO₂ adsorption functions was developed. PVA-PEI-PAC materials were selected as the gel raw materials, and an orthogonal test with three factors and three levels was used to optimize the gelation time parameters to identify the optimal formulation. The microstructure of the gel, CO₂ adsorption performance, as well as its inhibition rate of CO, a marker gas of coal spontaneous combustion, and its effect on activation energy were systematically characterized through SEM, isothermal/temperature-programmed/cyclic adsorption experiments, and temperature-programmed gas chromatography. The results show that the optimal gel formulation is 14% PVA, 7% PEI, and 5.5% PAC. The gel microstructure is continuous, dense, and rich in pores, with a CO₂ adsorption capacity at 30 °C and atmospheric pressure of 0.86 cm³/g, maintaining over 76% efficiency after five cycles. Compared with raw coal, a 10% gel addition reduces CO release at 170 °C by 25.97%, and the temperature-programmed experiment shows an average CO inhibition rate of 25% throughout, with apparent activation energy increased by 14.96%. The gel prepared exhibited controllable gelation time, can deeply encapsulate coal, and can efficiently adsorb CO₂, significantly raising the coal–oxygen reaction energy barrier, providing an integrated technical solution for mine fire prevention and extinguishing with both safety and carbon reduction functions. Full article

(This article belongs to the Special Issue Gels for Adsorption and Separation)

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