Gels doi: 10.3390/gels12060508

Authors: Kun Fang Pei Li Xiangrui Huang Hanbing Wang Yihan Li

The emergence of organic–inorganic hybrid composites integrating magnetic nanoparticles (MNPs) with polymers has been an important advancement in modern biological research. Among these systems, magnetic sodium alginate (SA)-based hydrogels (MSABHs), produced by embedding MNPs within an SA framework, exhibit remarkable potential for biomedical applications owing to their high biocompatibility, rapid magnetic response, controllable spatiotemporal behavior, and remote, non-invasive operation. Under the influence of an alternating magnetic field (AMF), MSABHs can exhibit various responses, including deformation, motion, and thermal generation, which are highly valuable for diagnostic and therapeutic medical applications. This review first outlines the key studies on SA and MNPs, along with the various synthesis routes used to fabricate MSABHs. Subsequently, the discussion primarily focuses on their versatile biomedical applications, including tissue engineering, targeted drug delivery, thermotherapy, imaging, and micro-robotics, followed by an evaluation of current challenges and prospects for future improvement. Through this comprehensive examination and synthesis, the review aims to further reveal the full potential of MSABHs and broaden their applications in the biological domain.

Gels doi: 10.3390/gels12060507

Authors: Fengfei Lou Sujun Dong Xia Liu Haitao Fan Xun Wang Keyong Zhu Yinwei Ma

Radiative heat transfer in aerogels (semi-transparent materials) acts as a participating medium, causing notable errors in conventional steady-state thermal conductivity measurements. Coupled conduction–radiation heat transfer is numerically simulated to examine the influence of variations in the heating plate-specimen interface emissivity on thermal conductivity measurements, and the simulation results are experimentally validated using test systems with differing interface emissivities. The results show that the effect of interface emissivity on effective thermal conductivity is more obvious under high temperatures and low extinction coefficients. When the average temperature is 1273 K, the emissivity decreases from 1 to 0.2, and the effective thermal conductivity with extinction coefficients of 3.5 m−1 and 3500 m−1 decreases by 76.1% and 24.1%, respectively. Experimental results show that when the hot surface temperature is 873 K, the cold surface temperature differences in different test systems can reach 30 K. The experimental results have the same trend as the steady-state simulation results, which verifies the accuracy of the numerical simulations. Quantitative analysis of the steady-state heating measurement results demonstrates the effect of medium radiation in semi-transparent materials on the obtained results. The findings contribute to a more accurate characterization of silica aerogel composites and provide new insights into the influence of radiative heat transfer on thermal conductivity evaluation in semi-transparent aerogel materials, which is important for the development and application of aerogel-based thermal insulation systems.

Gels doi: 10.3390/gels12060506

Authors: Ying Kuang Ting Zhang Hui-Yu Liu Jia-Peng Wu Wen Luo Kai Chen Hong Qian Kao Wu Cao Li

To address the poor solubility, instability, and low oral bioavailability of quercetin (Q), Q-loaded nanoparticles (Q@DDZ) were fabricated using deamidated zein peptide (DDZ) via a pH-driven method. As a food-grade hydrophilic colloid, DDZ effectively improves the colloidal stability of the delivery system. Deamidation increased hydrophilic amino acids and surface negative charge. DDZ bound Q via static quenching with a higher binding constant (Ka = 2.25 × 103 L/mol) and more binding sites (n = 1.7561) than zein, along with stronger hydrogen bonding and hydrophobic interactions. Q@DDZ exhibited higher encapsulation efficiency (45.36–87.32%) and loading capacity (1.82–12.27%) than Q@zein, with a smaller particle size and better dispersibility. At 50.0 μg/mL Q, Q@DDZ showed 41.06% (DPPH) and 46.62% (ABTS) higher scavenging rates than free Q. It displayed excellent stability under acidic, high ionic strength, and thermal conditions (80 °C, 180 min). In simulated digestion, Q@DDZ delayed Q release in the oral and gastric phases and prolonged intestinal release, which indicated potentially improved bioavailability. This study provides mechanistic insights into deamidation-modified plant protein delivery systems for hydrophobic bioactives, offering new perspectives for the development of functional biopolymer gel materials.

Gels doi: 10.3390/gels12060505

Authors: Juan Carlos Rendón-Angeles Zully Matamoros-Veloza Diego Emiliano Carrillo-Ramírez José Remigio Quiñones-Gurrola Kazumichi Yanagisawa

The sol–gel coprecipitation method is highly efficient for synthesising a wide range of binary perovskite solid solutions (SSs), which have been under exhaustive study due to their semiconductor and catalytic properties. Therefore, we conducted a systematic study to extend the chemical stability of the cubic structure in Zr4+-rich SS in the system SrTiO3–SrZrO3. The proposed new approach involves in situ gel coprecipitation and simultaneous hydrothermal processing, which was conducted at standard conditions (200 °C for 6 h) in a KOH (5 M) solution under stirring at 130 rpm. The formation of the cubic perovskite-structured SS occurred in the compositional range from 10.0 to 100.0 mol% Ti4+. The particle crystallisation was achieved via the dissolution-crystallisation mechanism, which proceeded rapidly, aided by preliminary gel dehydration and vigorous stirring. The prepared particles, either orthorhombic or cubic, have a unique morphology, resembling a pseudocuboidal shape with rounded edges. The particle size decreases as the Ti4+ content in the SSs increases, due to improved gel solubility. The band gap of the cubic intermediate SSs is sharp, ranging from 3.12 to 3.57 eV; thus, these perovskites can be applied in the development of semiconductor devices and in catalysis. These powders can also be employed as cool pigments due to their high NIR solar irradiance of 80.22%.

Gels doi: 10.3390/gels12060504

Authors: Andreea Smeu Ioana Olariu Iasmina Marcovici Diana Haj-Ali Lavinia Vlaia Vicențiu Vlaia Alina Tănase Raluca Mioara Cosoroabă Vlad Socoliuc Cristina Adriana Dehelean

The skin serves as the first line of defense, being highly prone to external damage. Silibinin (SIL) exerts skin-protective properties, but its topical use requires a suitable delivery system. Despite the growing interest in proniosomal platforms loaded with natural products, their application for the cutaneous delivery of SIL remains scarcely explored. This study proposes the pharmaco-technical characterization and preclinical safety evaluation of a SIL-loaded proniosomal gel (SIL-PG) for skin application. SIL-PG was produced using the coacervation phase separation technique, analyzed in terms of physicochemical and technological properties, and evaluated in vitro and in ovo for potential cytotoxic and irritant effects. SIL-PG retained a yellowish, creamy aspect, proper rheological behavior and spreadability, gradual in vitro drug release, sustained permeation, and an adequate safety profile, evidenced by the lack of cytotoxicity in HaCaT keratinocytes and spheroids and the absence of irritant potential in 3D EpiDerm™ reconstructed human tissues and on the chorioallantoic membrane. Overall, these findings emphasize SIL-PG as a potential pharmaceutical formulation for dermal use, with favorable pharmaco-technical characteristics and in vitro–in ovo biocompatibility.

Gels doi: 10.3390/gels12060503

Authors: Nan Wang Tingting Liu

In ulcerative colitis (UC), the therapeutic efficacy of nanoparticle (NP)-based drug delivery systems is limited by premature drug release, uptake or degradation of NPs during their passage through the harsh gastrointestinal tract (GIT) environment, poor colon targeting, and rapid NP clearance caused by diarrhea symptoms. This study focused on designing an advanced spatiotemporally controlled nanohybrid hydrogel drug delivery system to overcome these challenges. We developed a pH- and temperature-responsive polysaccharide-based hydrogel composed of chitosan (CS), β-glycerol phosphate disodium salt pentahydrate (GP), hydroxypropyl cellulose (HPC), and collagen type I (Col I), designated as CS/HHPC/Col I-GP. The hydrogel exhibited a dense and uniform porous reticular structure, with an average pore diameter of 127.45 ± 2.22 μm. The equilibrium swelling ratio of the CS/HHPC/Col I-GP was determined to be 32.10 ± 1.11 g/g, indicating excellent swelling capacity and sustained structural stability over 6 h—making it suitable for sustained drug release in the intestinal tract. Then, the prepared curcumin nanoparticles (CurNPs) were encapsulated into the CS/HHPC/Col I-GP hydrogel to form the CS/HHPC/Col I-GP-CurNPs composite. The polysaccharide-based hydrogel shell of the formulation withstood harsh gastrointestinal conditions, enabled targeted adhesion to the colon, and was specifically degraded by colonic enzymes. The CurNPs released in the colon benefit from their negatively charged characteristics, enabling accumulation at the positively charged inflamed sites and achieving sustained Cur release. The results of the gastrointestinal digestion simulation experiment showed that the cumulative release of CS/HHPC/Col I-GP-CurNPs was only 12.33 ± 2.17% in simulated gastric fluid (SGF) and reached 96.91 ± 1.98% in simulated colonic fluid (SCF) after 60 h. Cell and animal experimental data confirmed that the formulation significantly alleviated colitis symptoms by modulating the repolarization of pro-inflammatory M1 macrophages to anti-inflammatory M2 phenotypes and deactivating the TLR4/MyD88/NF-κB pathway. Furthermore, the integrity of the intestinal mucosal barrier and the gut microbiota were enhanced. This study provides a promising strategy for the oral drug treatment of UC.

Gels doi: 10.3390/gels12060502

Authors: Jinjing Cao Fang Huang Zhenhao Jiang Qijin Ge Zeyu Liu Zheng Zhao Feng Chen Yukun Zhu Changpo Zhang Peng Wang Dongying Wang Chuizhou Meng

Poly(3,4-ethylenedioxythiophene) (PEDOT)-based gels have emerged as a prominent class of functional conductive materials, owing to their unique electromechanical coupling characteristics that integrate electrical functionality and mechanical adaptability. This review systematically elucidates the electromechanical properties of PEDOT-derived gels—defined as the synergistic response of electrical behaviors (conductivity, carrier mobility, electrochemical stability) and mechanical performances (flexibility, stretchability, tensile strength, bending resistance)—under mechanical deformation, as well as their mutual regulatory mechanisms. Focusing on how preparation processes and structural regulation modulate these electromechanical properties, this work first introduces the development history, intrinsic conductive mechanisms, and inherent electromechanical characteristics of PEDOT. It then systematically summarizes mainstream synthesis methods, analyzing their effects on balancing mechanical flexibility and electrical conductivity. Addressing the brittleness and poor electromechanical stability of pure PEDOT, this review further explores composite synergistic mechanisms with conductive/non-conductive polymers, metallic materials, inorganic nanoparticles, and biomaterials, clarifying how interfacial interactions optimize mechanical deformability while preserving or enhancing electrical performance. Finally, it summarizes the applications of PEDOT-based composites in electromechanically compatible fields including flexible sensing, micro/nano patterning, implantable biomedicine, anti-corrosion protection, and energy storage. This review aims to clarify the connotation of PEDOT’s electromechanical properties, refine the focus of relevant research, and provide a theoretical basis for designing high-performance PEDOT-based gels with balanced electromechanical properties.

Gels doi: 10.3390/gels12060501

Authors: Myoung Joon Jeon Youjin Seol Youjin Jeong Sayan Deb Dutta Ki-Taek Lim

Effective wound management remains a critical challenge in modern medicine, requiring a delicate balance among infection control, hemostasis, and tissue regeneration. Biopolymer-based hydrogels have emerged as leading candidates for medical use due to their biocompatibility, moisture-retention capabilities, and structural similarity to the natural ECM. This review provides a comprehensive overview of the transition from passive dressings to intelligent, multifunctional hydrogel scaffolds. We first examine the biological mechanisms of wound healing and the fundamental roles of hydrogels in maintaining an optimal microenvironment. Central to this discussion is the integration of conductive materials (including conductive polymers, carbon-based nanomaterials, and metal nanoparticles), which empower hydrogels with bio-sensing and electromechanical stimulation capabilities. Furthermore, we explore how 3D printing technologies enable the fabrication of personalized, high-precision scaffolds. The review also discusses the emerging role of integrated monitoring systems and machine learning algorithms in enhancing diagnostic accuracy. By synthesizing current research, this review identifies critical engineering hurdles and outlines the future trajectory toward automated, closed-loop wound-care systems in clinical practice. Ultimately, while these advanced electronic scaffolds offer revolutionary therapeutic paradigms, this review underscores that balancing electroconductivity with chronic cytocompatibility, refining multi-modal biosensor calibration, and navigating complex regulatory evaluation pathways remain critical prerequisites. Overcoming these fundamental translational bottlenecks is essential to realizing the next generation of automated clinical wound care.

Gels doi: 10.3390/gels12060500

Authors: Mobinul Islam Md. Shahriar Ahmed Yoomin Kim Jemin Yeon Jihun Kim Ye-Chan Oh Md. Mahmudul Hasan Hyerim Hong Yuchae Hwang Kyung-Wan Nam

The growing demand for efficient and sustainable energy storage systems has intensified research on advanced materials for lithium–ion batteries (LIBs). Gel-based synthesis routes—particularly polymeric and chelating gel techniques—have emerged as powerful methods for designing lithium–ion battery (LIB) anode materials with tailored microstructures, composition uniformity, and enhanced electrochemical performance. These methods facilitate the transformation of solution-phase precursors into homogeneous and finely structured materials, enabling precise tuning of physicochemical properties. This review provides a comprehensive overview of the fundamental principles of polymeric and chelate gel synthesis routes, highlighting their ability in controlling particle size, morphology, and phase purity. Their applicability to a wide range of anode materials, including transition metal oxides and silicon-based composites, is discussed. The manuscript highlights LIBs anode material developments via gel precursor chemistry, structure–property relationships, and future directions toward scalable and sustainable electrode manufacturing.

Gels doi: 10.3390/gels12060499

Authors: Jingjing Zhang Ning Liang Dingli Su

This study investigates in situ hydrogel formation and its regulating effect on multiscale damage evolution in red sandstone subjected to chemical–wet–dry cycles. Uniaxial compression, X-ray diffraction, scanning electron microscopy coupled with energy-dispersive spectroscopy, mercury intrusion porosimetry, and inductively coupled plasma mass spectrometry tests were performed to characterize mechanical degradation, mineral alteration, pore-network evolution, ion migration, and gel micromorphology. By combining multiscale experimental characterization with a segmented statistical damage constitutive model, this study describes the hydrogel-mediated damage evolution of red sandstone under chemical–wet–dry cycles. The mechanical properties of red sandstone show nonlinear degradation, with a deterioration order of acidic > alkaline > neutral, and this effect intensifies with increasing cycle number. After 15 cycles at pH = 3, the compressive strength and elastic modulus decreased by 38.21% and 27.12%, respectively. Both acidic and alkaline environments promoted pore development in red sandstone. After 15 cycles at pH = 3, the porosity increased from 21.51% to 24.51%, and the most probable pore diameter shifted from 21.32 μm to 25.88 μm. The porosity increased by 2.86% at pH = 11, and in situ hydrogels formed under alkaline conditions partially filled pores and inhibited crack propagation. The developed model effectively reproduced the mechanical evolution of red sandstone, with all fitted results showing R2 values no lower than 0.92. These findings provide a basis for evaluating hydrogel-regulated damage in red sandstone and support the application of in situ gel materials in geotechnical engineering.

Gels doi: 10.3390/gels12060498

Authors: Jiaxuan Di Yan He Chao Sun Jingna Jia Xing Zheng Xinyu Li

Articular cartilage has attracted significant attention for its essential roles in joint lubrication and stress buffering. However, its inherent self-repair capacity is limited. Addressing inflammatory damage to this tissue, therefore, presents a major clinical challenge in orthopedics. Poly(vinyl alcohol) (PVA)-based hydrogels have emerged as promising repair materials due to their high water content, which mimics the properties of natural cartilage, as well as their tunable mechanical properties and favorable biocompatibility. This review comprehensively examines PVA-based hydrogels, beginning with an overview of their network formation. It then systematically summarizes the main methods and principles for constructing their networks, including physical crosslinking (e.g., cyclic freezing-thawing), chemical crosslinking, and radiation crosslinking, as well as targeted strategies to enhance performance and modify functionality. Particular emphasis is placed on their diverse clinical applications in treating osteoarthritis, primarily including their use as surgical adjuncts, such as injectable gels and anti-adhesion membranes, as long-term or biodegradable cartilage replacement implants, and their potential in partial joint surface resurfacing and reconstruction. Finally, prospects for the application of PVA-based hydrogels in osteoarthritis therapy are considered. Overall, as versatile platform materials, PVA-based hydrogels demonstrate significant potential for clinical translation in cartilage repair.

Gels doi: 10.3390/gels12060496

Authors: Dongmei Jiang Yingjun Wang

This study presents a sodium alginate/chitosan/activated carbon (SA/CS/AC) gel microspheres loaded with Citrus reticulata peel allelochemicals for continuous inhibition of Microcystis aeruginosa by controlled release. Preparation parameters were optimized via response surface methodology (RSM) for improved algal inhibition, yielding an optimal formulation: 1.97% SA, 0.76% CS, 0.31% AC. The optimized gel microspheres showed a 7-day inhibition rate of 85.17 ± 2.49%, consistent with the predicted 85.29%. Characterization revealed that AC optimized the gel’s porous structure and surface functionality, providing more adsorption sites for allelochemicals. This helps improve the loading capacity of the gel microspheres and enables stable sustained release, with a cumulative release of 70% over 25 days. Algal inhibition declined slightly from day 7 to 30 due to allelochemical depletion but remained 76.27%, versus 30.58% for the blank SA/CS/AC carrier and 52.81% for the allelochemical-loaded SA/CS gel microspheres. AC thus synergistically strengthens algal inhibition by elevating allelochemical loading and prolonging activity, providing a feasible strategy for sustainable cyanobacterial bloom control.

Gels doi: 10.3390/gels12060497

Authors: Babar Azeem KuZilati KuShaari

Polysaccharide hydrogel-based fertilizer carriers have emerged as promising alternatives to conventional synthetic systems due to their biodegradability, tunable physicochemical properties, and ability to regulate nutrient release through structure–transport interactions. However, their performance is still predominantly evaluated using simplified aqueous testing methods that fail to capture the complexity of real soil environments. This review provides an engineering-oriented analysis of nutrient release behavior from polysaccharide-based hydrogel systems, emphasizing the limitations of conventional aqueous evaluation and their implications for predicting field performance. The discussion integrates material design, transport phenomena, and environmental interactions to establish structure–property–release relationships governing nutrient delivery. Conventional aqueous testing methods are critically examined in terms of experimental configuration, performance metrics, and kinetic modeling approaches, highlighting their tendency to overestimate swelling, neglect ionic and biological interactions, and ignore external transport resistances. The influence of soil-dependent factors, including moisture dynamics, pH, ionic strength, microbial activity, and soil structure, is systematically analyzed to demonstrate their coupled effects on swelling, diffusion, and degradation-controlled release mechanisms. Comparative evidence reveals a consistent laboratory–soil mismatch, where aqueous systems predict faster release rates and shorter durations compared to soil conditions. Based on these insights, key gaps in current evaluation practices are identified, particularly the lack of soil-representative testing protocols and the limited applicability of models derived from aqueous systems. Finally, an engineering framework is proposed for soil-relevant evaluation and improved predictive modeling, aimed at supporting the rational design and scalable implementation of next-generation hydrogel-based fertilizer carriers.

Gels doi: 10.3390/gels12060494

Authors: Luon Tan Nguyen Patrick Kai Xuan Lim Wenjuan Jin Yanli Zheng Quang M. N. Phan Meng Wang Duc Anh Tran Y. B. Guo V. P. W. Shim Huy-Du Do Thanh-Tan Nguyen Hieu Tran-Van Nga H. N. Do Hai M. Duong

Osteoarthritis is the most prevalent age-related joint disease, yet the limited regenerative capacity of articular cartilage severely constrains spontaneous repair. Here, we present a freeze–thaw polyvinyl alcohol (PVA)/polyethylene glycol (PEG) hydrogel platform featuring a hybrid open–closed macroporous architecture that enables cartilage-mimetic load dissipation for artificial cartilage applications. The hybrid porous structure provides synergistic advantages, where closed pores enhance load-bearing stiffness while open pores facilitate energy dissipation. By systematically tuning polymer composition and processing conditions, clear structure–property relationships among porosity, water content, and mechanical performance are established. An optimized formulation (18 wt.% PVA, 85–124 kDa; 18 wt.% PEG; three freeze–thaw cycles) yields hydrogels with high water content (39.1 ± 7.8 wt.%), high compressive Young’s modulus (3.60 ± 0.67 MPa), and excellent resilience under cyclic loading. Notably, under dynamic compression (2 m/s), a frequently overlooked yet physiologically relevant mechanical property of hydrogels, the materials exhibit nearly twofold enhancement in compressive modulus compared to static conditions, demonstrating pronounced strain-rate-dependent stiffening. Finite element analysis reveals efficient load redistribution across the interconnected porous network, providing mechanistic insight into the observed mechanical robustness. Compared with native cartilage and recently reported hydrogel systems, the developed hydrogels exhibit superior stiffness while maintaining mechanical and structural resilience. In vitro cytotoxicity and direct-contact assays confirm excellent cytocompatibility. These results establish a scalable and cost-effective design strategy for engineering mechanically robust, rate-adaptive hydrogels, advancing the development of next-generation artificial cartilage substitutes.

Gels doi: 10.3390/gels12060495

Authors: Tarek Dayyoub Kabiru Haruna Mohannad Mayyas

Polymeric fibers represent a vital class of functional materials due to their versatile properties, such as wide availability, low cost, recyclability, biodegradability, and excellent mechanical and chemical stability. Polymer fibers can be fabricated at both micro- and nanoscale dimensions using a variety of processing techniques. This review provides a comprehensive overview of the principal methods employed for polymer fiber preparation, including electrospinning, melt and solution blowing, dry and wet spinning, template synthesis, phase separation, and self-assembly. The technical principles, as well as the advantages and limitations, of each technique are systematically discussed. The review also explores polymeric fibers as smart materials for actuation applications. Particular focus is given to stimulus-responsive fiber systems such as shape memory fibers, hydrogel fibers, liquid crystal fibers, and electroactive polymers. Overall, this review establishes a coherent framework linking polymer fiber fabrication strategies with structure–property–function relationships, offering practical guidance for material selection and accelerating the development of next-generation smart polymer fibers for advanced actuation and multifunctional applications.

Gels doi: 10.3390/gels12060493

Authors: Jiangmei Cao Yutong Wang Hongchao Zhang Yanan Lu Jie Wu Haihua Li Wenyan Wang Xu Duan Xing Gao

Sports injuries, especially musculoskeletal and neurological types from strenuous exercise, are a global public health challenge. Characterized by a high incidence and slow recovery, these injuries differ from typical trauma, often resulting in severe mechanical transmission loss and an imbalanced immune microenvironment. Consequently, standard interventions struggle to achieve true tissue regeneration. Gelatin, a collagen-derived biomaterial, offers RGD-mediated cell adhesion, MMP-responsive degradation, and high modifiability. These qualities make it an excellent foundation for biomimetic repair scaffolds. This paper reviews the design principles and recent advances in gelatin-based multifunctional hydrogels in sports medicine. First, we analyse their structure and engineering advantages. Next, we summarise strategies and mechanisms for modules like conductivity, antibacterial activity, self-healing, stimulus responsiveness, and tissue adhesion. The review links these modules to types of injuries: bone or cartilage, tendon or ligament, skeletal muscle, spinal cord, and peripheral nerve. It clarifies their clinical and translational value in remodelling immune microenvironments, regulating electrophysiology, promoting interfacial regeneration, and restoring motor function. This review provides focused insights from materials science and sports rehabilitation to advance precision treatments for sports injuries.

Gels doi: 10.3390/gels12060492

Authors: Rong Tian Han Yi Jiaoyang Liu Tong Wang Tianyue Jiang Song Qin

Diabetic foot ulceration is a severe and common chronic complication of diabetes, accompanied by excessive reactive oxygen species (ROS) accumulation, persistent bacterial infection, prolonged inflammation, and insufficient angiogenesis. Traditional single-function wound dressings fail to simultaneously resolve these pathological barriers, leading to unsatisfactory healing outcomes. In this study, we developed a multifunctional composite hydrogel (E/MGel) by introducing mussel adhesive protein (MAP) into methacrylated hyaluronic acid (mHA) to construct an antibacterial and antioxidant delivery system, which was further loaded with epidermal growth factor (EGF) to promote angiogenesis. The as-prepared E/MGel exhibited a uniform porous structure, favorable rheology, high swelling ratio, and sustained protein release behavior. In vitro results demonstrated that E/MGel exerted potent antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli (E.coli), high ROS scavenging efficiency, good cytocompatibility, and remarkable pro-angiogenic effect on endothelial cells. In a mouse model of diabetic MRSA-infected full-thickness skin defect, E/MGel significantly accelerated wound closure, reduced bacterial burden, downregulated pro-inflammatory cytokines, promoted collagen deposition, and enhanced neovascularization. Meanwhile, no obvious systemic toxicity was observed. Taken together, this multifunctional hydrogel integrates antibacterial, antioxidant, and pro-angiogenic capacities to break the pathological vicious cycle of diabetic wounds, providing a promising and safe strategy for the clinical treatment of diabetic infected wounds.

Gels doi: 10.3390/gels12060491

Authors: Hyeon Ji Jeon Bo Yeong Park Ju Hyun Min Gyu Ri Shin Hye Min Jeong Kwang Yong Seol Ju-Hoon Lee Younghoon Kim Jungwoo Yang Young Hoon Jung

Probiotics can promote gut health, but their efficacy is often limited by low viability and metabolic activity in the gastrointestinal (GI) tract. This study aimed to develop protective hydrogels for encapsulating Lactiplantibacillus plantarum CJLP 133 using a composite matrix of sodium alginate (SA) and cellulose nanofibers (CNFs). L. plantarum CJLP 133-loaded hydrogel beads were fabricated via the ionic gelation technique using an optimized formulation of SA and CNF. Scanning electron microscopy revealed that CNF integration improved spherical morphology with reduced surface cracking. Fourier transform infrared spectroscopy confirmed the formation of intermolecular hydrogen bonds between SA and CNF. CNF integration also reduced gumminess and chewiness, resulting in a softer texture. The survival rate of L. plantarum CJLP 133 remained high following thermal exposure and freeze-drying. The in vitro GI delivery system demonstrated a protective swelling profile in stimulated gastric fluid and a targeted, highly efficient release profile in stimulated intestinal fluid. Finally, the 3% SA + 0.5% CNF hydrogel with L. plantarum CJLP 133 exhibited significant synbiotic effects, enhancing probiotic growth, intestinal adhesion, and butyrate and succinate production. These results suggest that the SA/CNF-based hydrogel is an effective delivery system that ensures the targeted release of probiotics within the GI tract.

Gels doi: 10.3390/gels12060490

Authors: György Szmirnov Ilona Szmirnova Ákos Tamás Nagy Gábor Kammerhofer Zsolt Németh Zsófia Zubor György Szabó

A propolis-based nano-formulated bioadhesive oral gel (NBF gel) containing vitamins C and E has been proposed as a supportive topical therapy for oral mucosal lesions. The aim of this study was to evaluate clinical outcomes associated with the use of the gel during a 15-year institutional clinical experience and to assess its adjunctive effect on periodontal status in patients with intellectual disabilities. The study consisted of two components: a retrospective observational case series and a non-randomized controlled clinical study. In the retrospective component, 295 patients (219 females and 76 males) received topical NBF gel treatment for various oral mucosal conditions, including xerostomia-associated mucositis, inflammatory lesions, aphthous ulcers, herpes infections, glossodynia, leukoplakia, erythroplakia, and post-surgical conditions. Treatment response was assessed descriptively using patient-reported symptom improvement combined with clinical evaluation. Overall, treatment was considered successful in 265/295 patients (89.8%), while 14/295 patients (4.7%) were classified as ineffective and 16/295 patients (5.4%) as inconclusive. More favorable responses were observed in inflammatory and post-treatment lesions than in potentially premalignant or neuropathic conditions. In the controlled periodontal component, 40 patients with mild to moderate intellectual disabilities were allocated into a control group performing toothbrushing alone and a test group additionally receiving topical NBF gel application. Periodontal status was assessed using the Basic Periodontal Examination (BPE) index at baseline and after 1 and 2 weeks. Adjunctive gel application was associated with greater improvement in periodontal status compared with toothbrushing alone. No clinically relevant adverse effects were documented during the observation period; however, because adverse events were not assessed using a predefined safety-monitoring protocol, these findings should be interpreted cautiously. The present findings suggest that the investigated nano-formulated bioadhesive oral gel may represent a potentially useful adjunctive topical therapy in selected oral mucosal and periodontal conditions. Further randomized controlled studies with standardized objective outcome measures are required to confirm these preliminary findings.

Gels doi: 10.3390/gels12060489

Authors: Airi Harui Michael D. Roth

Systemic administration of antibodies that target immune checkpoint inhibitor pathways is a highly effective approach to cancer immunotherapy, but systemic toxicity can limit clinical utility. In preclinical testing, a peri-tumor injection of a low dose of hydrogel-encapsulated cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) antibody was shown to selectively activate T cells in tumor-draining lymph nodes, induce tumor infiltration by cytotoxic T cells, and result in tumor regression, protective immunity, and long-term survival. In contrast to systemic therapy, there was limited systemic exposure or risk for autoimmune toxicity. The current study focuses on translating this platform into a biocompatible human therapeutic. The hydrogel matrix was reformulated using a low-molecular-weight hyaluronic acid. A recombinant human hyaluronidase (rHuPH20) was incorporated to promote lymph node targeting and self-resorbing features. Formulations were optimized to operate at neutral pH and with gelation kinetics allowing a 5 to 10 min administration window. Performance features were assessed including the capacity to encapsulate human IgG or ipilimumab antibody at proposed therapeutic doses (1–15 mg/mL), impact of rHuPH20 and antibody on rheologic properties and three-dimensional microstructure, and payload delivery profiles in vitro and in vivo. Results confirm the capacity for this unique hydrogel platform to be adapted for human testing.

Gels doi: 10.3390/gels12060488

Authors: Junjie Wang Yi Ju Yang Lei Jieyu Zhang Yunbing Wang

Cell culture is foundational to biomedical advancements, yet its widespread clinical and practical distribution is severely constrained by the high infrastructural costs of cryogenic logistics and the physical stressors of liquid-phase transit. Herein, we propose a proof-of-concept cryogen-free cell transportation strategy leveraging a rapid reversible thermoresponsive collagen (RRTC) hydrogel regulated by simulated body fluid (SBF). Operating via temperature-driven physical network assembly and disassembly rather than chemical crosslinking or chemical modifications, the RRTC system undergoes a rapid sol-to-gel transition within 60 s at 37 °C for efficient cell encapsulation, and completely reverses to a free-flowing sol state within 60 s at 4 °C to facilitate enzyme-free, non-destructive cell retrieval. Using L929 fibroblasts as a standardized benchmarking cell model, the biophysical protection of the matrix was systematically evaluated under both static simulated transit (48 h and 120 h) and real-world trans-city courier transportation (an approximate 50 h round trip via SF Express) within a passively temperature-shield configuration. The SBF-regulated 3D physical confinement successfully shielded cells from manual handling, multi-axis shipping vibrations, and environmental thermal fluctuations. Post-transport evaluations demonstrated that the encapsulated cells maintained a high viability above 90% and a stable recovery yield of approximately 78%, while exhibiting robust subsequent 2D re-adhesion and sustained re-culture capacity. This thermoresponsive matrix provides a potential matrix for short-term cryogen-free cell transportation and post-transport recovery, while further studies using additional cell types, longer transportation periods, and functional assays are required to evaluate its broader applicability.

Gels doi: 10.3390/gels12060487

Authors: Wenyao Zhang Changjin Xu Jiuyang Wang Riqing Cheng Huiqing Guo

To address the limitations of the tumor microenvironment (TME) and the inadequate efficacy of standalone chemodynamic therapy (CDT), this study developed a tannic acid-copper coordination gel-coated mesoporous Cu2O nanodelivery system (Cu2O@TA@5-FU) for synergistic enhanced CDT and chemotherapy. The system exhibits a high specific surface area (98 m2·g−1) and mesoporosity, achieving a 5-fluorouracil (5-FU) loading efficiency of 46.2%. Under simulated TME conditions, the nanodelivery system displayed markedly accelerated drug release and enhanced catalytic activity, indicative of pronounced TME responsiveness. In vitro, the Cu2O@TA support efficiently catalyzed a Fenton-like reaction with H2O2 to generate cytotoxic hydroxyl radicals (·OH) while depleting overexpressed intracellular GSH, thereby disrupting antioxidant defenses and amplifying oxidative stress. Combined with the antiproliferative action of released 5-FU, the synergistic treatment reduced 4T1 cell viability to approximately 23%, accompanied by sharp declines in intracellular ATP and GSH levels. This work overcomes the systemic toxicity of free 5-FU and the instability of Cu2O by employing a protective and stimuli-responsive TA-Cu coordination gel shell, offering a reliable strategy for TME-responsive synergistic nanotherapeutics that disrupt tumor metabolic and redox homeostasis.

Gels doi: 10.3390/gels12060486

Authors: Daniel González-Nieto José Pérez-Rigueiro Francisco J. Rojo Fivos Panetsos Gustavo V. Guinea

Direct cellular reprogramming, the conversion of one somatic cell type into another, represents a remarkable advancement in regenerative medicine. Its potential to transform fibrotic tissue into functional parenchyma underscores its therapeutic promise. However, several critical challenges remain unresolved, including limited reprogramming efficiency, the long-term functional stability of converted cells, their integration within pre-existing cellular circuits, and safety concerns related to transgene integration and immunological responses to reprogramming-based viral vectors. Approaches based on the exogenous administration of recombinant proteins and miRNAs have also emerged, though these rely on factors that are naturally prone to exhaustion and degradation, potentially restricting their efficacy. This review is divided into three main sections. The first part addresses direct cellular reprogramming in the context of other cell-based applications, outlining its main applications and current biological limitations. The second part examines how different biomaterials, ranging from hydrogel scaffolds to nanoparticles, can modulate direct cellular reprogramming by providing mechanical and topographical cues and by enabling tighter control over the concentration and spatiotemporal dynamics of reprogramming factors and viral vectors. The third part discusses key findings in biomaterial-assisted reprogramming strategies, highlighting emerging opportunities for clinically translatable approaches. The convergence of regenerative biology and biomaterials science may ultimately generate advanced gel-based and hybrid cellular reprogramming platforms for in vitro testing and, in situ applications, for promoting cell fate stabilization and facilitating the regeneration of damaged tissues and organs.

Gels doi: 10.3390/gels12060485

Authors: André Cruz Andreja Lesac Nataša Šijaković Vujičić Francisco J. Galindo-Rosales

Liquid crystal physical gels (LCPGs) combine the anisotropic properties of liquid crystals with the structural stability of soft solids. In this work, MBBA-based LCPGs were prepared using chiral oxalamide gelators 1,6-bis((O-leucylmethanol)-N-yloxalamido)hexane (6-O-Me) and 1,9-bis((O-leucylmethanol)-N-yloxalamido)nonane (9-O-Me) and thoroughly characterized for their thermal, rheological, and electrorheological behaviours. Techniques included differential scanning calorimetry, oscillatory rheology, electrorheological testing, and advanced microscopy analysis. A custom microfluidic device was developed for in situ application of an electric field and optical assessment of its influence on microstructure formation. Both gels exhibited distinct gel-like behavior, with storage moduli consistently exceeding loss moduli and sustained network stability under both short- and long-term deformations. The gelators had minimal effect on the isotropic–nematic transition of MBBA but efficiently delayed crystallization, extending the stability window by −8 °C for 9-O-Me and −14 °C for 6-O-Me. When subjected to electric fields, the gel network weakened in the nematic phase, and the fiber assembly during cooling was altered, resulting in the formation of thicker, anisotropic fibers, consistent with microscopic observations. These results illustrate how the properties of LCPGs can be tuned through molecular design and external stimuli, expanding their potential for stimuli-responsive soft matter applications.

Gels doi: 10.3390/gels12060483

Authors: Óscar Brandón-Basdediós Laura Miguélez-Riádigos Esther Pinilla-Peñalver Mateo Alonso Paula Sánchez Luz Sánchez-Silva Juan Luis Sobreira-Seoane

The growing demand for sustainable and energy-efficient materials has positioned aerogels as promising candidates for advanced insulation applications. Among them, polyurethane (PU) aerogels are attracting increasing interest due to their thermal insulation properties and mechanical versatility. However, their development commonly relies on trial-and-error experimentation, which is time-consuming and resource-intensive. This study presents a Digital Twin (DT) framework to support PU aerogel design and reduce the experimental workload. A pilot-scale DT was developed using data from 21 synthesis experiments, including process configuration, parameter mapping, model development, and process analysis. Two predictive models were evaluated, with the Support Vector Regression (SVR) model showing good agreement with the experimental data (R2 = 0.964) and being selected to estimate aerogel density within the parameter range studied. The DT framework enabled the identification of synthesis conditions associated with lower density, which may contribute to improved thermal insulation performance. These results illustrate the potential of DT-assisted modelling to support material development, improve process understanding, and guide more efficient experimentation in PU aerogel synthesis. Overall, this work highlights a data-driven approach for advancing sustainable and scalable aerogel manufacturing.

Gels doi: 10.3390/gels12060484

Authors: Dan Gao Junqiang Huang Zhenhua Duan Qingli Xie Yuthana Phimolsiripol Pornchai Rachtanapun Noppol Leksawasdi

Hemp seed protein hydrolysate (HSPH), despite its high digestibility and solubility, exhibits severely impaired gelation properties due to extensive hydrolysis, thereby limiting its food applications. This study analyzed the effect of homogeneously incorporating commercial hemp seed protein concentrate (HSPC) into HSPH on physicochemical and structural properties of the resultant composite gels. As the HSPC concentration increased from 100 to 150 mg/mL, the composite gels exhibited a significant enhancement in hardness (p < 0.05), increasing from 1.63 to 5.74 N, along with an improvement in water-holding capacity (WHC) from 45.52 to 55.46 g/g. Concurrently, the storage modulus (G′) and gelation temperature increased, with the latter rising from 65 to 78 °C. SDS-PAGE analysis suggested that the enhanced composite gel properties were attributed to its high-molecular-weight protein fractions (10–15 kDa and 40–50 kDa) of HSPC, which functioned as the primary structural components of the gel network. In addition, the formation of denser yet irregular microstructures was observed by scanning electron microscopy (SEM) analysis when HSPC incorporation increased from 0 to 200 mg/mL. Fourier-transform infrared (FTIR) further suggested that these improvements were due to increases in β-turn and random coil contents by approximately 9.60 and 7.73%, respectively. These findings provided insights into the utilization of HSPH and HSPC in plant-based foods and contributed to food security and sustainable agriculture.

Gels doi: 10.3390/gels12060482

Authors: Emmanuel Anegbe Cesare Oliviero Rossi Iolinda Aiello Nicolas Godbert Eugenia Giorno Darren A. Makeiff Pietro Calandra Paolino Caputo

The demand for eco-friendly viscosity modifiers in food, cosmetics, and lubricants has increased, promoting the development of high-performance, sustainable materials. Low-molecular-weight gelators (LMWGs) are promising candidates, though their behavior in complex systems remains underexplored. In this study, a novel alkylamido isophthalic acid-based LMWG (AIPA–gallic acid) was synthesized. Its performance was evaluated in vegetable oil, mineral oil, and cocoa butter using rheological measurements across varying concentrations and temperatures, with all dynamic rheological measurements conducted in the viscoelastic region. Cacao butter is solid at 15 °C, so the flow curve that can be obtained at this temperature should show high values not comparable with the other liquid oils. No slippage phenomenon was observed. Using a step-rate protocol before acquiring the flow curves, no time-dependent behavior (thixotropy) was observed. Frequency and flow sweep tests were used to assess viscoelastic properties, interaction strength, and coordination number. Results revealed that incorporating AIPA–gallic acid at 4 wt% increased the viscosity by 74 times (at 25 °C) in mineral oil, compared to an increase of about four orders of magnitude in vegetable oil. This suggests the formation of intermolecular interactions that lead to an increased momentum transport process, which is significantly higher in vegetable oil. In contrast, cocoa butter exhibited minimal rheological changes, suggesting that no gelation occurred. Analysis using the weak gel model confirmed that viscosity enhancement arises from a structured network in mineral and vegetable oils, but not in cocoa butter. Temperature-dependent variations in structural parameters further highlight the role of molecular interactions between the gelator and the oil matrix.

Gels doi: 10.3390/gels12060481

Authors: Hongjian Wu Xiangwei Kong

A critical challenge in coalbed methane (CBM) extraction is the severe formation damage induced by conventional foam fracturing fluids, primarily through polymer retention and hydrogen bond disruption within the microporous matrix. This study presents a molecularly engineered, low-damage foam fracturing fluid that leverages synergistic nanoparticle–surfactant interactions to construct a robust interfacial pseudo-gel network, thereby decoupling effective fracture stimulation from adverse geochemical damage. The primary novelties of this work are threefold: (i) establishing a direct, quantitative cause-and-effect relationship between molecular interfacial architecture and reservoir protection, (ii) proposing a comprehensive “interfacial control” design paradigm that engineers viscoelasticity at the gas–liquid interface rather than through bulk polymer gelation, and (iii) demonstrating the complete decoupling of foam stability from formation damage in a polymer-free system. A systematic optimization methodology was employed: initial foaming agents were screened via the Waring Blender method, evaluating foam volume, half-life, and a derived comprehensive index; subsequently, synergistic binary surfactant mixtures and foam stabilizers were assessed to formulate the final systems. An optimized formulation, designated Foam System I (0.5 wt.% fluorosurfactant FK + 0.5 wt.% nano-silica RX + 2.0 wt.% KCl), demonstrated exceptional foam quality (Γ = 77.1 ± 1.5%) and kinetic stability (T1/2 > 350 s). Rheological characterization confirmed shear-thinning behavior conforming to the Herschel–Bulkley model (n = 0.38–0.42, R2 > 0.98) and a structural recovery of 92.5 ± 2.1%—comparable to crosslinked polymer gels but achieved without any bulk viscosifier. Core flood analyses revealed that Foam System I induced a permeability damage of only 12.75 ± 1.8%, representing a 55–75% reduction compared to polyethylene glycol (PEG)-stabilized reference fluids (28.36–51.91%). X-ray photoelectron spectroscopy (XPS) correlated this enhanced reservoir compatibility with an 18.0 ± 2.0% suppression of oxygen-containing functional group adsorption, attributed to the steric hindrance conferred by the fluorinated hydrophobic moieties. This work establishes an “interfacial control” paradigm wherein gel-like stabilization for proppant transport is achieved via interfacial viscoelasticity rather than bulk polymer gelation, thereby directly addressing the critical imperative to harmonize fracture conductivity with reservoir protection in unconventional energy development. The findings are validated for shallow CBM reservoir conditions (25–35 °C), with extension to higher-temperature formations identified as a priority for future investigation.

Gels doi: 10.3390/gels12060480

Authors: Noman Sohail Thomas Fischer Marion Martienssen

The long-term application of immobilized quorum quenching (QQ) bacteria requires carrier materials with sufficient mechanical stability and durability across various operating conditions. This study aims to enhance the durability and stability of polyvinyl alcohol (PVA) beads and to evaluate their performance for long-term operation. The beads were synthesized using two PVA brands with different molecular weights (MWs), and the effect of cross-linking conditions and reagent purity on bead stability was also investigated. Primarily, their physical strength was evaluated under centrifugal forces. Additionally, polyvinyl alcohol and sodium alginate (PVA-SA) beads were incorporated with cellulose to enhance their strength. The structural and chemical characteristics of the beads were examined using scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). The results showed that PVA 100 kDa beads withstood centrifugal forces up to 11,000 rpm without breakage, whereas lower MW (PVA 85 kDa) beads failed at 5000 rpm. Bead quality was critically sensitive to calcium chloride purity, as impurities and reduced Ca2+ availability caused poor crosslinking and structural collapse. The results revealed that PVA 100 kDa increases the number of polymer chain entanglements and intermolecular interactions, which enhance the structural integrity. Bead quality is strongly influenced by the purity of calcium chloride in the crosslinking solution, as well as by the solution pH. SEM analysis showed that cellulose-incorporating beads exhibited a denser and more uniform pore structure, with median equivalent pore diameters reduced from 50 µm (PVA-SA) to 22.4 µm upon cellulose incorporation, while maintaining sufficient porosity for nutrient diffusion. Similarly, FTIR analysis confirmed that cellulose was successfully integrated, with increased hydroxyl interactions and modified C–O vibrational characteristics, indicating strong hydrogen bonding within the composite matrix. Principal component analysis (PCA) confirmed that hydroxyl interactions and C–O vibrational modes are the main contributors to spectral variation, indicating that cellulose acts as a structural modifier in the PVA-SA network. These results demonstrate the effectiveness of this strategy in designing durable PVA-SA-cellulose based composite beads for long-term QQ applications.

Gels doi: 10.3390/gels12060479

Authors: Chenghao Zhang Jingbin Yang Zhongyi Wang Mengyao Wang Yuan Liu

To address the poor temperature resistance of conventional gel breakers, the uncontrollable gel-breaking time, and the risk of secondary reservoir damage during temporary plugging of fractured formations with polymer gels, a high-temperature-resistant double-shell encapsulated gel breaker, UF-EC/SA, was prepared using oil-phase phase separation combined with in situ polymerization. In this material, urea-formaldehyde resin (UF) served as the outer shell, ethyl cellulose (EC) as the inner shell, and sulfamic acid (SA) as the core. Unlike conventional single-shell persulfate or directly added acid breakers, this double shell design integrates a thermally resistant UF barrier, a diffusion-controlling EC layer, and an acid core to delay premature gel degradation while enabling subsequent cleanup. The physical structure and sustained-release behavior of the capsules were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), powder X-ray diffraction (XRD), and conductivity measurements. The compatibility between the encapsulated breaker and the polymer gel, as well as the effects of salinity and breaker dosage on the rheological properties of the gel, were investigated. The regulatory effects of temperature and capsule dosage on gel-breaking performance were studied in detail. In addition, high-temperature/high-pressure displacement experiments were conducted to evaluate the temporary plugging performance of the gel containing the encapsulated breaker in fractured cores and packed-sand tubes. The results showed that the prepared capsules had good sphericity and a dense shell structure, with an encapsulation efficiency of 76.7%. The capsules exhibited temperature resistance up to 150 °C and favorable sustained-release characteristics. The UF-EC/SA breaker showed good compatibility with the polymer gel and did not inhibit gelation within the temperature range of 80–150 °C or at dosages of 0–16 wt.%. The gel maintained good mechanical strength even in highly mineralized brines. At 150 °C and a capsule dosage of 16 wt.%, the gel was completely broken within 2.5 d; the residue concentration was only 351 mg/L, and the residue size was mainly distributed within 100–500 μm. The high-temperature/high-pressure displacement tests demonstrated that the gel containing 16 wt.% capsules achieved a maximum breakthrough pressure of 5.16 MPa in a 3 mm wedge-shaped fracture core, and the pressure remained stable for 5 d. After gel breaking, the residue could be readily flowed back, indicating excellent synergy between temporary plugging and subsequent gel breaking. Therefore, the UF-EC/SA encapsulated breaker provides a new technical option for efficient gel breaking in high-temperature fractured formations.

Gels doi: 10.3390/gels12060477

Authors: Han Fu Qiwen Yao Shuai Tan Yingming Wang Aishun Jin

Porous hydrogels are critical for tissue engineering and regenerative medicine, as they mimic the native extracellular matrix to support cell infiltration and mass transport. A common strategy for engineering pore structures involves the incorporation and subsequent removal of sacrificial porogen templates (e.g., crystals or microspheres). Although this approach offers excellent control over pore architecture, it often suffers from complex procedures and biosafety concerns arising from incomplete template removal. In this work, we present a simple, biocompatible, and versatile templating approach. By systematically investigating the coacervation parameters, we produced gelatin microspheres (GSs) with tunable diameters from 7 µm to 300 µm via a green, instrument-free, and scalable process. Using GSs of 20–160 µm as porogens, we obtained alginate hydrogels with adjustable viscoelasticity, stiffness, and pore sizes. We then validated two cell-loading strategies for bulk porous alginate hydrogels using immortalized human T (Jurkat) cells: (i) post-seeding into pre-formed pores supported high-density, long-term, and organized cell aggregates with >90% viability; (ii) in situ encapsulation (prior to pore formation) yielded >80% viability and preserved the cluster-forming growth characteristics of Jurkat cells. Moreover, composites of smaller GSs (7–20 µm) with alginate could be syringe-extruded into stable, sub-millimeter porous filaments, demonstrating the potential for 3D printing. Collectively, this work provides a promising platform for three-dimensional culture of immune cells.

Gels doi: 10.3390/gels12060478

Authors: Paula Kaufelde Anete Vircava Ingus Skadiņš Kristiāna Rubeze Jevgenijs Proskurins Konstantīns Logviss Agnese Brangule

Sterilization is essential for hydrogel-based biomaterials, but it can also determine the final material state. This study used ionically crosslinked alginate hydrogels as a model system to evaluate sterilization as a coupled process linking microbial inactivation and hydrogel structural reorganization. Steam sterilization, gamma irradiation, ethylene oxide (EtO), ultraviolet (UV) irradiation, and high hydrostatic pressure (HHP) treatment were assessed within the same model system. Microbiological effectiveness was assessed using surface- and matrix-associated contamination models, while structural responses were evaluated by rheology, dimensional changes, and swelling behavior. Steam sterilization, gamma irradiation, EtO, and selected HHP conditions resulted in no detectable microbial growth under the tested conditions, whereas UV irradiation was insufficient to eliminate detectable growth from matrix-associated contamination. However, microbiologically effective treatments produced distinct material profiles. Steam generated a compact and stiff hydrogel state, gamma irradiation produced softened but deformation-tolerant networks, EtO caused pronounced dimensional alteration and high deformability, and HHP produced softened, water-accessible hydrogels with parameter-dependent responses. These findings show that sterilization method selection should integrate microbial inactivation with the final structural state required for application-specific hydrogel performance.

Gels doi: 10.3390/gels12060476

Authors: Xiaoli Wang Xinyu Zhao

Conventional strategies for synthesizing porous structures generally depend on template-based methods, which involve not only excessive consumption of templating agents but also the use of hazardous chemicals, such as hydrofluoric acid or strong alkalis. Therefore, designing an effective and convenient strategy to fabricate porous SnO2 is of significant practical relevance. Herein, we developed a top-down strategy to fabricate SnO2 electrode via a thermal oxidation gas-release route, resulting in a bulk 3D hierarchical architecture with interconnected porous channels. Employing a bottom-up strategy, the gel precursors of these porous SnO2 materials were synthesized on a large scale via a simple, surfactant- and template-free route, in accordance with green chemistry principles. The results show that the porous SnO2(300) electrode materials possess a high specific surface area and exhibit favorable electrochemical energy-storage performance, achieving a high specific capacitance of 267.31 F g−1 at a current density of 1 A g−1. Furthermore, based on the gel electrolyte of PVA/KOH, an asymmetric supercapacitor device assembled using porous SnO2(300) materials as the positive electrode and activated carbon as the negative electrode (denoted as P-SnO2//AC) achieves an energy density of 32.49 Wh kg−1 at the power density of 718.97 W kg−1. This work presents a simple, cost-effective, environmentally friendly and scalable approach to synthesize SnO2 materials with an advanced structural design.

Gels doi: 10.3390/gels12060475

Authors: Jiali Wang Long Chen Jiayin Zhang Yu Sang Yunhai Zhao Hui Mao

To address wellbore instability and the technical challenges associated with high-density water-based drilling fluid loss control in deep shale gas formations of the Sichuan-Chongqing region in China, a novel nano-micro sealant designated CLG-Seal was synthesized via molecular structural optimization. The molecular structure of newly developed CLG-Seal exhibits distinct core–shell structural characteristics. The inorganic nano-silica constitutes the rigid core of CLG-Seal, which guarantees its plugging performance. The hydrophobically associating polymer which is coated on the surface of nano-silica constructs the flexible shell of CLG-Seal, endowing the CLG-Seal with excellent gel-forming capacity, adhesion film-forming capacity, deformability and perfect dispersibility. Transmission electron microscopy and scanning electron microscopy were employed to characterize the morphology of the CLG-Seal nanomicron-scale plugging agent. The sealing performance and underlying mechanisms of CLG-Seal were subsequently evaluated via particle plugging apparatus tests, displacement experiments, and etched glass micromodel simulations. Field trials conducted in the third section of Well WY3-2-3HF validated the application effectiveness of this agent in drilling fluid systems. The results indicate that the nano-micro sealant CLG-Seal exhibits a median particle size of D50 is 146 nm, which can be modulated by adjusting the synthesis conditions. The nano-micro sealant CLG-Seal significantly mitigates fluid loss in low-permeability microfractures and fissures. Notably, a concentration of merely 3% is sufficient to achieve optimal nano-micro plugging performance. The results of the mechanism study indicate that while the CLG-Seal particles are close to each other, the polymer chains with flexible long chain structure which are coated on the surface of nano-silica constructs tend to be intertwined, forming a cross-linked network structure of gel film, thereby increasing the interaction between nano-micron particles and forming an impermeable plugging film. In addition, due to the nanoscale effect, the CLG-Seal has a strong tendency to adsorb onto the surface of shale rock through hydrogen bonding with the shale matrix. The hydrophobically associating polymer with high elastic modulus and excellent mechanical properties can enhance the pressure-bearing capacity of the filter cake through elastic deformation. Therefore, these nano-micron particles can form a strong sealing film on the filter cake and at the micropores of shale rock, thereby creating a dense mud cake on the outside of the shale formation. Field trial results demonstrate that the incorporation of the nano-micro sealant CLG-Seal into the drilling fluid for the third section of Well WY3-2-3HF reduced the PPA fluid loss to 4.6 mL. This value represents a substantial reduction compared to adjacent wells and signifies a remarkable improvement over the drilling fluids previously employed in the Longmaxi Formation of this block. Furthermore, the treated drilling fluid exhibited a superior filtration control pressure capacity of 10.5 MPa. The operation was completed successfully without any lost circulation or wellbore instability, and achieved a drilling footage of 42 h with an average penetration rate of 7.81 m/h. The mud weight was reduced by approximately 0.08–0.10 g/cm3 compared to offset wells. These results confirm the excellent application efficiency of the newly developed CLG-Seal in field operations.

Gels doi: 10.3390/gels12060474

Authors: Otávio Simões Girotto Maria Angelica Miglino Giovanna Ayumi M. Fukuda Caliandra Bernardi Cristiane Lurdes Paloschi Talissa Caroline Pollon Fernando Gonçalves da Silva Petronio Fernando Chissico Matheus Henrique Herminio Garcia Vinicius Gabriel Silverio Scholl Sandra Maria Barbalho Rogerio Leone Buchaim Daniela Vieira Buchaim Vivien Patricia Garbin Samara Silva de Souza

Since current therapies cannot regenerate lost myocardium or reverse adverse ventricular remodeling—major contributors to worldwide cardiovascular mortality—advanced biomaterials, particularly hydrogels, have emerged as promising therapeutic platforms. Among these, bacterial nanocellulose (BNC) has gained increasing attention due to its hydrated nanofibrillar architecture, high crystallinity, robust mechanical performance, and excellent water-retention capacity, features that closely resemble key aspects of the native extracellular matrix. These properties provide a favorable microenvironment for cell adhesion, survival, and tissue organization in cardiovascular applications. Preclinical evidence suggests that BNC-based cardiac constructs, including acellular patches and cell-laden systems, may reduce post-infarction ventricular dilation, promote angiogenesis, and improve cellular engraftment. In vascular tissue engineering, BNC has also been explored in small-diameter grafts, anisotropic hydrogel systems, and shape-memory conduits with encouraging hemocompatibility and functional durability. Functional modifications—including gelatin incorporation, oxidative surface treatments, peptide grafting, conductive polymers, and structural alignment strategies—further expand the biological and mechanical versatility of BNC-based systems. In addition, BNC-containing bioinks have demonstrated promising rheological behavior, printability, and cell compatibility for 3D bioprinting applications. Despite these advances, important challenges remain, including optimization of material functionalization, host integration, degradation control, vascularization, scalable manufacturing, and regulatory translation toward clinical application.

Gels doi: 10.3390/gels12060473

Authors: Junjie Xu Hui Gao Jianlong Chang Lijun Lei Feng Liu Pengyong Xie Yuan Cao

This study realizes the synergistic improvement in mechanical properties and ablation resistance of Si-modified phenolic aerogel composites with preserved lightweight characteristics and excellent thermal insulation. The resin matrix forms a uniform nanoporous structure, providing prominent thermal insulation performance. The composite with a fiber density of 0.62 g/cm3 has a low thermal conductivity of 0.086 W/(m·K). The material exhibits reliable tensile strength within a wide temperature range, and its tensile strength rises significantly with an increase in fiber density. The composite with a fiber density of 0.62 g/cm3 delivers a tensile strength of 129 MPa at 20 °C and 102 MPa at 300 °C, which are 79.4% and 122.2% higher than those of the composite with a fiber density of 0.36 g/cm3. In addition, methyltriethoxysilane and quartz fiber knitted felts form in situ SiO2 and SiC ceramic cladding layers under high-temperature ablation, effectively enhancing the ablation resistance of the composites. Higher fiber density greatly reduces the linear ablation rate. With an oxygen flow of 950 L/h and acetylene flow of 700 L/h, the linear ablation rate of the composite with a fiber density of 0.62 g/cm3 is only 0.13 mm/s, 23.1% lower than the composite with a fiber density of 0.36 g/cm3.

Gels doi: 10.3390/gels12060472

Authors: Yidian Li Yunyi Gong Xuejiao Wang Yongshuai Ma Rui Chai Zhenna Zhang Chaofan Guo Junjie Yi

Extrusion-based three-dimensional food printing requires inks that can be smoothly extruded while maintaining sufficient structural stability after deposition. In this study, gelatin and κ-carrageenan were first mixed and then subjected to post-mixing pH regulation before spray drying, producing composite powders with different structural states. These powders were incorporated into yellow peach pulp gels to prepare fruit-based printing inks, and their printing performance, extrusion behavior, mechanical properties, particle-size distribution, and microstructure were systematically evaluated. The results showed that the structural state formed during gelatin–κ-carrageenan powder preparation was closely associated with the extrusion stability and shape retention of the final inks. Among the tested formulations, the ink prepared with gelatin–κ-carrageenan powder pre-regulated to pH 4.0 exhibited the best overall printability. Although its pore-area fidelity was slightly lower than that of the sample pre-regulated to pH 3.5, it produced more stable multilayer cylinders and better-defined lattice structures. In addition, the pH 4.0 sample showed the lowest and most stable extrusion force and the highest Young’s modulus, indicating a favorable balance between extrusion flowability and post-deposition support. Microstructural observations and particle-size analysis suggested that pH regulation altered the aggregation state and local morphology of the gelatin–κ-carrageenan system. Samples prepared at higher pH values tended to form larger and less uniform aggregates, which was unfavorable for stable extrusion and shape retention. Overall, post-mixing pH regulation of gelatin–κ-carrageenan provides a practical strategy for improving the printing-related properties of fruit-based gel inks.

Gels doi: 10.3390/gels12060471

Authors: Beibei Wang Xuetong Sun Hao Sun Jiacheng Yu

Bone repair is a complex and dynamic process that demands implanted scaffolds to provide temporal-specific functions: antibacterial activity in the early stage, followed by angiogenic and osteogenic stimulation in later stages. This study introduces a biomimetic scaffold composed of a filled Gel-OSA hydrogel and a 3D-printed PLA framework, enabling sequential multi-drug release for bone regeneration. Zero-dimensional arginine-derived carbon dots were incorporated into the hydrogel to achieve rapid release after implantation, conferring potent antibacterial activity and ROS regulation. Meanwhile, chondroitin sulfate (CS)-loaded mesoporous bioactive glass nanoparticles were immobilized onto the 3D-printed PLA surface via a polydopamine coating, allowing sustained release of CS and Ca/P ions to enhance the scaffold’s long-term osteoinductive capability. The composite scaffold further demonstrated combined effects in promoting cell proliferation and osteogenic differentiation in vitro. Collectively, these findings suggest that this biomimetic scaffold, designed for temporally controlled multi-drug release, represents a promising therapeutic strategy for the reconstruction of bone tissue.

Gels doi: 10.3390/gels12060470

Authors: Peiji Liu Yinfeng Wang Hong Lin Jingxue Wang

Development of efficient and robust endotoxin removal approaches is vital for safeguarding the safety and functional performance of bacteriophage formulations and recombinant protein bioproducts. Here, a stacked gel-casting strategy combined with carboxymethyl chitosan (CMCS) reinforcement was employed to construct a mechanically robust PMB-functionalized cryogel. The synergistic effects of the stacked architecture and CMCS reinforcement significantly enhanced pore-wall stability and functional site accessibility, resulting in a high endotoxin adsorption capacity (1.88 × 106 EU/g) and excellent reusability (>90.30% removal efficiency after six cycles). The cryogel also demonstrated effective endotoxin removal in complex biological samples, achieving >99.00% removal in bacteriophage preparations with improved phage recovery and >99.99% clearance in recombinant protein solutions. These results highlight a promising strategy for endotoxin control in phage-based applications and biopharmaceutical purification.

Gels doi: 10.3390/gels12060469

Authors: Qianbing Lin Guanyu Chen Ruiqiang Dong Xinyue Cui Shiyu Zhang Daoyong Li Xinzhe Li Lianghui Guo

Water channeling during water injection in mid-to-late development stages of low-permeability reservoirs in Xinjiang leads to a rapid water cut increase and reduced oil displacement efficiency, causing significant economic losses. This study systematically investigated two chemical systems—a polyurethane (PU) plugging system and a urea-formaldehyde (UF) plugging system—under simulated Xinjiang reservoir conditions. The PU plugging system formulation was optimized through control variable experiments, and both systems were evaluated for rheological properties, curing behavior, mechanical strength, salinity and temperature adaptability, and plugging performance using sand-pack displacement tests. The optimized PU plugging system cured at 80 °C for 1 h achieved a maximum plugging rate of 96% and a breakthrough pressure gradient of 4.2 MPa·m−1. The UF plugging system exhibited distinct temperature-triggered gelation, with viscosity rising exponentially above 60 °C, providing a plugging rate of 70% and a breakthrough pressure gradient of 1.0–2.0 MPa·m−1, suitable for deep fluid diversion. The PU plugging system offers high-strength near-wellbore plugging, while the UF plugging system enables controllable deep fluid diversion. Their complementary properties provide a comprehensive technical strategy for water channeling control in different low-permeability and high-temperature reservoirs in Xinjiang Oilfield.

Gels doi: 10.3390/gels12060468

Authors: Xuecui Song Jing Guo Wei Chen Mengya Liu Yihang Zhang Wenhui Xiao Fucheng Guan

Recently, conductive hydrogels have gained extensive applications in flexible wearable electronics and have garnered considerable attention. However, their inherent swelling behaviour and limited mechanical strength have hindered their further development. In this study, a polyacrylamide/sodium alginate (PAM/SA, PS)-based hydrogel with high mechanical strength and anti-swelling properties was prepared by combining mechanical stretching–drying pretreatment with a bimetallic ion (Li+/multivalent metal ion) post-soaking strategy. Among multivalent metal ions (Ca2+, Al3+, and Zr4+), the Al3+-crosslinked hydrogel (PS-Al3+) demonstrated outstanding overall performance. It exhibited excellent mechanical properties, with tensile strength, elongation at break, and impact strength reaching 9.71 MPa, 993.53%, and 75 MJ/m3, respectively. Its dense network structure also gave it excellent anti-swelling properties (swelling ratio of 14%). As a strain sensor, the PS-Al3+ hydrogel displayed good conductivity (1.33 S/m), high sensitivity (GF = 2.25), fast response (response time of 403 ms), and negligible hysteresis (recovery time of 407 ms). Benefiting from its exceptional resistance to expansion, the material’s sensor response signals in underwater environments are highly consistent with those in air. Furthermore, this sensor has been successfully applied to swimming motion monitoring and data transmission in underwater environments. This study proposes a novel, low-cost, and simple approach for developing flexible sensors suitable for underwater environments.

Gels doi: 10.3390/gels12060467

Authors: Lingfeng Kou Huan Yang Yunquan Zheng

In this study, a novel composite hydrogel was developed based on oxidized sodium alginate (OSA), synthesized via sodium periodate oxidation, and incorporated into a carboxymethyl chitosan (CMCS) matrix. Scallop active peptides (SAPs), a marine-derived bioactive component with outstanding antioxidant and pro-regenerative activities, was introduced to endow the hydrogel with enhanced biological functions, which is of great significance for breaking the functional limitations of traditional single-component hydrogels. The construction of a dynamic covalent network, driven by the Schiff base reaction, was confirmed through structural characterization using FT-IR and 1H-NMR. The hydrogel exhibited favorable physicochemical properties, including shear-thinning behavior, significant self-healing capability, and a uniform porous microstructure that effectively mimics the extracellular matrix (ECM). In vitro evaluations revealed excellent biocompatibility and potent pro-angiogenic potential, as evidenced by enhanced HUVEC migration and tube formation. In a rat model of full-thickness skin wounds, the CMCS/OSA/SAPs hydrogel significantly accelerated wound closure and promoted re-epithelialization and organized collagen deposition. Furthermore, immunohistochemical analysis confirmed upregulated VEGF and α-SMA expression, alongside reduced inflammatory levels (decreased iNOS), indicating potent tissue-regenerative and immunomodulatory functions. Overall, this work presents a multifunctional hydrogel system that integrates antioxidant, anti-inflammatory, and tissue-regenerative properties, offering a promising strategy for deep-wound healing. This study highlights the significant potential of marine-derived bioactive proteins/peptides in the development of advanced biomedical materials.

Gels doi: 10.3390/gels12060466

Authors: Lixia Wang Guorong Lin Lijun Fu

The gelation property is one of the core functional characteristics of konjac glucomannan (KGM). KGM mainly forms gels through ionic crosslinking, deacetylation and compounding with other colloids. Exploring novel gelation technologies for the precise regulation of KGM gel properties is the research focus in this field. In this work, an alternating current (AC) electric field was applied to trigger KGM gelation in the presence of calcium chloride (CaCl2). The structure and viscoelastic properties (including storage modulus G′, loss modulus G″ and loss factor tanδ) of the gels were analyzed by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy (RS), scanning electron microscopy (SEM), X-ray diffraction (XRD), simultaneous differential scanning calorimetry/thermo-gravimetric analyzer (DSC/TGA) and rheometer. FTIR and RS revealed that KGM underwent partial degradation and deacetylation under the AC electric field. Calcium ions and chloride ions dissociated from CaCl2 are adsorbed onto the hydroxyl groups of KGM molecules. KGM molecules constituting the gels still retain partial original acetyl groups. SEM images showed that the gels had a porous structure with a coarse surface. XRD patterns showed the gels contained complex CaCl2 hydrates. Simultaneous DSC/TGA analysis indicated that the gel with excellent thermal stability exhibited distinct melting endothermic peaks corresponding to CaCl2 hydrates. Rheological data showed that, apart from KGM concentration, G′ and G″ of the gels gradually increased with the elevation of CaCl2 concentration, applied voltage and electric treatment duration. However, when CaCl2 concentrations, voltage, and electric treatment time exceeded their respective critical values, both started to decrease. Taking G′ as the evaluation index, the optimal preparation conditions for KGM-CaCl2 electrogel were determined as follows: KGM 0.5%, CaCl2 1.2%, electric treatment duration 45 min, and voltage 24 V.

Gels doi: 10.3390/gels12060465

Authors: Haofeng Wang Nongawendé S. Gloria Saguin Hao Lan Jingrong Gao Yadong Zhao Shanggui Deng

This study investigated the development, fabrication, and characterization of a novel biodegradable food packaging film based on chitosan (CH) and fucoidan (FU), incorporating blackcurrant-derived anthocyanins (BCAs). The system was designed to enable real-time monitoring of tuna (Thunnus spp.) freshness, while addressing environmental concerns through the replacement of synthetic materials with a bioactive, multifunctional alternative that provides both mechanical protection and dynamic spoilage indication. Films were prepared using a casting method with varying BCA concentrations (0.2%, 0.4%, and 0.6%) and systematically evaluated in terms of their structural, physicochemical, and biological properties. The results indicated that the CH/FU/BCA film containing 0.4% BCA exhibited optimal performance, characterized by enhanced tensile strength, reduced water solubility and moisture content, and improved thermal stability and barrier properties. The incorporation of BCA enabled distinct color changes in response to spoilage-related conditions, supporting its function as a pH-responsive indicator. In addition, the films demonstrated significant antimicrobial activity against Escherichia coli and Staphylococcus aureus, affirming their suitability as active packaging materials. Zeta potential analysis further indicated improved colloidal stability upon BCA incorporation. Overall, the synergistic interactions among CH, FU, and BCA resulted in a multifunctional film with combined protective and freshness-indicating capabilities. These findings highlight the potential of the developed biofilm for application in intelligent seafood packaging systems.

Gels doi: 10.3390/gels12060464

Authors: Rui Li Chang Xu Qiannuo Gu Xiaoyang Pan Andong Qian Xuning Leng

A sustainable alginate-based composite adsorbent was developed by valorizing soy whey wastewater for the efficient removal of copper (II) ions from aqueous solutions. Soy whey wastewater/sodium alginate/cellulose (SWWSAC) beads were fabricated via a controlled slow-release calcium ion cross-linking strategy. This strategy resulted in homogeneous gelation, effective encapsulation of wastewater-derived organics and the formation of a hierarchical mesoporous structure. Compared with pure sodium alginate (SA) and sodium alginate–cellulose (SAC) beads, the SWWSAC beads exhibited a significantly higher specific surface area (3.95 m2/g) and pore volume (0.021 cm3/g), thus having markedly enhanced copper (II) ion adsorption performance. Batch adsorption experiments demonstrate that the adsorption process was strongly dependent on solution pH, adsorbent dosage, contact time and initial metal concentration. Kinetic analysis indicates that the adsorption process followed a pseudo-second-order model, while equilibrium data were well described by the Langmuir isotherm, corresponding to monolayer chemisorption. Based on this isotherm, SWWSAC beads had a theoretical maximum adsorption capacity of 168.3 mg/g (25 °C), 190.8 mg/g (35 °C), and 204.4 mg/g (45 °C). Thermodynamic results reveal that the adsorption was spontaneous and endothermic. FTIR and XPS analyses confirm that copper (II) ion removal was governed by synergistic complexation involving carboxyl, hydroxyl, carbonyl, and protein-derived nitrogen-containing functional groups. Moreover, the SWWSAC beads had a copper (II) ion removal efficiency of (92.4 ± 0.4)% and retained 73.3% of their initial adsorption capacity after six regeneration cycles in actual electroplating wastewater treatment. In this process, the beads exhibited good anti-interference performance against coexisting cations and good structural stability. Therefore, this work demonstrates an effective and low-cost strategy for copper (II) ion removal while providing a value-added route for the sustainable utilization of soy whey wastewater.

Gels doi: 10.3390/gels12060463

Authors: Jiawei Han Peng Zhang Xiaobing Dai Canhua Lai

Geopolymer gel concrete (GPC) is a kind of environmentally friendly concrete, which has become a potential alternative material to replace ordinary concrete. Traditional mix design of GPC is carried out under experimental conditions, which is time-consuming and labor-intensive. Geopolymer concrete (GPC) is intended for use in hydraulic structures, which are often exposed to water environments. Water flow exerts significant abrasion and erosion on these structures. If the abrasion resistance (AR) of the material is poor, the service life and service quality of hydraulic structures will be substantially reduced under the action of water flow. Therefore, AR is a key performance indicator for GPC in hydraulic engineering applications. This abrasion resistance can be enhanced by using fibers (for example, steel fibers, polyvinyl alcohol (PVA) fibers, and basalt fibers) and nanomaterials. Furthermore, there is a complex nonlinear relationship between the proportions of fibers and nanoparticles added and the properties of GPC. In this study, the circular ring test method and the underwater steel ball test method were conducted to investigate the AR of nano-SiO2 (NS) and hybrid fiber (NHF) reinforced geopolymer gel concrete (NHF-GPC). A backpropagation (BP) neural network (BPNN) model optimized by the Grey Wolf Optimizer (GWO) (GWO-BPNN) is established to predict the abrasion resistance strength (ARS) and the abrasion rate of NHF-GPC based on the circular ring test method. In addition, the ARS, abrasion rate, and average abrasion depth (AAD) based on the underwater steel ball test method were also predicted. The results indicate that the GWO-BPNN model demonstrates superior performance over the standard BPNN, exhibiting higher prediction accuracy, better fitting performance, and faster convergence speed. Specifically, for the circular ring test method abrasion rate prediction, GWO-BPNN reduced the root mean square error (RMSE) by 30.3% and lowered the mean absolute percentage error (MAPE) to 8.4%. The GWO-BPNN model established in this study can provide efficient and reliable theoretical support for the optimization of the NHF-GPC mix design.

Gels doi: 10.3390/gels12060462

Authors: Tianjiao Zhao Lei Huang Sihan Wei Chengci Liu Jinhua Xu Lu Qiao Jincheng Li Chaoying Zhang Yingchun Mu Zhiyang Zhao Meitong Li Xin Hu

Aerogels derived from microbial exopolysaccharides are useful in the food, pharmaceutical, and environmental sectors, but their application in anticancer therapy is constrained by inadequate characterization, especially regarding effects on normal cells. This study used ethanol precipitation and trichloroacetic acid deproteinization to extract crude exopolysaccharide from the fermentation broth of Bacillus amyloliquefaciens SQ-2. The pure fraction, EPS-3791, was obtained using Sephadex G-100 gel filtration chromatography and DEAE cellulose ion exchange. The weight–average molecular weight of EPS-3791 was 64.4 kDa. Monosaccharide analysis indicated fructan as the dominant component, which was consistent with the results of methylation analysis and NMR spectroscopy, confirming that EPS-3791 is a fructan mainly linked by →1)–Fruf–(2→bonds. UV scanning indicated high purity. FTIR analysis revealed functional groups including hydroxyl, carbonyl, and C–O–C groups. EPS-3791 exhibited a porous three-dimensional network morphology by SEM, with a decomposition temperature of 191.61 °C by TGA. Additionally, aerogels were prepared by freeze drying. EPS-3791 aerogels demonstrated minimal cytotoxicity to normal L929 cells while inhibiting the growth of human lung cancer A549, breast cancer MCF–7, and cervical cancer HeLa cells in a dose-dependent manner. Scratch wound healing experiments revealed that EPS-3791 aerogels hindered HeLa cell migration while promoting L929 wound closure. These findings identify EPS-3791 as a fructan-type exopolysaccharide aerogel with specific anticancer properties.

Gels doi: 10.3390/gels12060461

Authors: Xingmei Sheng Qi Cui Siyan Huang Zibo Song Xueming Xu Junjie Yi Chaofan Guo Yongshuai Ma

This study evaluated the effects of tamarind seed polysaccharides (TSP) on the quality characteristics and in vitro starch digestibility of steamed buns made from doughs with different freezing storage times (0, 30, and 60 days). The pore structure, specific volume, water distribution, and starch digestibility were analyzed. TSP significantly altered the dough microstructure by increasing pore density and pore volume while reducing the average pore area, forming a more uniform pore network. During freezing storage, the specific volume of control samples decreased, whereas steamed buns with 1–2% TSP maintained a relatively high specific volume (~1.65) after 60 days, indicating improved gas retention and structural stability. TSP also increased bound water and restricted water migration. Additionally, TSP increased resistant starch (RS) from 15.96% to 24% and reduced rapidly digestible starch (RDS). Overall, TSP improved the structural stability of frozen steamed buns by regulating water distribution, strengthening the gluten-starch network, and altering starch digestibility. These findings provide insights into the use of natural polysaccharides to enhance the quality and nutritional function of frozen wheat-based foods.

Gels doi: 10.3390/gels12060460

Authors: Minghang Zhao Yulu Xie Pengbo Wang Xuyu Hao Yutong Xu Dongyang Zhao Zhengxiong Wang Hao Chen

The development of stable and efficient essential oil delivery systems remains a persistent challenge in active food packaging applications. This research aimed to develop a multi-functional soy protein isolate (SPI)-based composite gel film integrating a tea tree oil micro emulsion (TME) via a microemulsion-in-gel approach, featuring sustained antioxidant release. The TME was first optimized using pseudo-ternary phase diagrams and exhibited excellent physicochemical stability. It maintained a droplet size ranging from 10 to 13 nm, with a polydispersity index (PDI) less than 0.2 under diverse stress situations (such as dilution, heat treatment, pH change, centrifugation, and 30-day storage). Afterward, TME-SPI composite gel films containing 1 to 3% TME were fabricated through solution casting and subsequent gelation of the protein matrix. The incorporation of TME markedly improved the properties of the gel film network. It raised the opacity by around 2.5 times, boosted the elongation at break to 144% (which is three times that of the control), and distinctively enhanced both water solubility and the water vapor barrier. Importantly, the 2% TME-SPI gel film exhibited sustained antioxidant activity from within the gel matrix, retaining more than 50% of its original 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity after 72 h, significantly outperforming films containing free TTO. The microemulsion-in-gel approach was shown to be effective in creating SPI-based gel films that possess combined light-barrier characteristics, adjustable moisture resistance, improved flexibility, and extended antioxidant release. This offers a promising framework for the next generation of active food packaging. Furthermore, the composite gel films exhibited concentration-dependent antibacterial activity against Staphylococcus aureus, with the 3% TME-SPI film achieving an 82% inhibition rate, thus experimentally validating its active packaging potential.

Gels doi: 10.3390/gels12060459

Authors: Mikhail M. Avdeev Vyacheslav S. Molchanov Alexander L. Kwiatkowski Yuri M. Chesnokov Akhmed Kh. Islamov Kuanysh Nazarov Olga E. Philippova

Wormlike micelles (WLMs) of surfactants are widely used as smart thickeners in various applications, including enhanced oil recovery. However, their thickening ability needs to be improved both at ambient and elevated temperatures. In the present paper, we propose to enhance the viscoelastic properties of surfactant solutions by incorporating carboxymethylated cellulose nanocrystals (CNCs). Upon addition of CNCs, dilute solutions of short WLMs acquire viscoelasticity and then transition into a viscoelastic solid state. This process is accompanied by an increase in the viscosity and storage modulus by up to five and four orders of magnitude, respectively. The observed effect of CNCs on the storage modulus and viscosity is greater than that of any of the previously studied WLM-CNC systems. It is attributed to the formation of a network of fibrillar-like aggregates composed of WLMs and CNCs, which was confirmed by cryo-TEM data. To our knowledge, such kind of aggregates have not been observed before. When CNCs are added to a transient network of long entangled WLMs, the viscoelastic solution transitions into a viscoelastic solid state, which results in an increase in the viscosity and storage modulus by up to two orders of magnitude. CNCs provide the WLM solution with greater resistance to heating, such that the storage modulus remains almost unchanged when the temperature increases from 20 to 70 °C. Moreover, a heat-induced gelation was observed. It was shown that higher concentrations of nanocrystals lower the critical gel temperature, indicating that they promote the gelation of the mixture. SANS data revealed that the local structures of both micelles and nanocrystals are preserved in the mixed system upon heating. According to ITC data, at room temperature, the interaction between surfactant ions and similarly charged nanocrystals is governed by both enthalpy and entropy, which suggests that hydrogen bonding plays a major role in this process, although hydrophobic interactions may also be involved. When the temperature increases to 60 °C, the aggregation becomes entropy-driven, indicating that hydrophobic interactions begin to dominate. The results obtained can expand the range of practical applications of WLMs as thickening agents, in particular, to higher-temperature conditions in deeper oil wells.

Gels doi: 10.3390/gels12060458

Authors: Dandan Chen Yan He Xinyue Zhang Longyi Nan Xin Jin Yan Zheng Chao Sun Jianpeng Guo Xinyu Li

Wound healing is a complex physiological process involving multiple stages, including hemostasis, inflammation, proliferation, and remodeling, which imposes high demands on the functionality and adaptability of wound repair materials. Hydrogels, as a class of novel materials, have become ideal wound dressings due to their excellent biocompatibility, breathability, and conformability. Sodium alginate-based composite hydrogels offer advantages such as readily available raw materials and mild preparation conditions. They can also endow materials with properties including antibacterial, anti-inflammatory, hemostatic, and pro-angiogenic effects, meeting the application requirements for multifunctional and highly efficient wound dressings. As a result, they have attracted considerable attention in the field of wound repair. This article introduces the preparation methods of physically and chemically crosslinked sodium alginate-based composite hydrogels, as well as the drug release mechanisms from these hydrogels. It elaborates on their applications in wound dressings, discusses key challenges including difficulties in large-scale preparation, high barriers to clinical translation, insufficient long-term in vivo stability, and low integration of intelligent functions, and outlines future research directions in terms of large-scale fabrication, regulatory compliance, long-term safety, and intelligent design. This review aims to provide a theoretical basis for the development of novel sodium alginate-based composite hydrogels for wound dressings and to promote their clinical translation and practical application in this field.

Gels doi: 10.3390/gels12060457

Authors: Ioana Maria Marinescu Andrada Serafim Elena Olaret Bogdan Stefan Vasile Mona Mihailescu Gratiela Gradisteanu Pircalabioru Kristin Syverud Stian Kreken Almeland Samih Mohamed-Ahmed Kamal Mustafa Esko Kankuri Cristian Botezatu Bogdan-Stelian Mastalier-Manolescu Alexandra Catalina Birca Izabela-Cristina Stancu

Modern wound care is challenged by the emergence of antibiotic-resistant bacterial strains, causing the need for advanced dressing materials that provide infection control while promoting healing. Although polyacrylamide (PAAm) hydrogels are widely investigated due to their biocompatibility, their lack of intrinsic antibacterial activity and poor mechanical properties restrict their clinical use. To overcome these limitations, this study proposes a natural–synthetic hydrogel that combines PAAm with TEMPO-oxidized cellulose nanofiber (TOCNF) functionalized silver nanoparticles (AgNPs). The synthesis is performed through the polymerization of the synthetic monomer in the presence of the TOCNF–AgNPs, the nanofibrillar cellulose simultaneously serving as a reducing and stabilizing agent for AgNPs, and as a plasticizer for the PAAm network. Morpho-structural analysis of the hybrid precursor (TOCNF–AgNPs) revealed two populations of AgNPs, offering a cumulative effect between rapid bacterial penetration and a prolonged ionic reservoir, while maintaining the stability of the system. The subsequent incorporation of the hybrid into PAAm matrix resulted in tunable swelling kinetics and mechanical properties. Wettability and surface stiffness improve with the increase in hybrid content. The antibacterial effect was confirmed by a colony-counting assay for formulations with higher AgNPs content, exhibiting inhibitory metabolic activity against several pathogenic strains. These results suggest that PAAm/TOCNF–AgNPs (PTA) nanocomposites represent a promising mechanically adaptive candidate for wound-care applications.

Gels doi: 10.3390/gels12060456

Authors: Awn Abbas Nanxin Li Sameera Naseer Lian Chen Xiaoyang Ai Yixing Chen Chongde Gu Hualin Fu

Gelatin methacrylate (GelMA) hydrogels are promising carriers for bioactive agents like curcumin (Cur) and adenosine diphosphate (ADP) in wound healing. However, existing GelMA-based systems fail to achieve both rapid hemostasis and sustained anti-inflammatory effects. In this study, we developed a Cur/ADP GelMA hydrogel, and evaluated its anti-inflammatory, regenerative, hemostatic, and biocompatible properties. Proton nuclear magnetic resonance (1H-NMR) analysis showed that a 65% degree of substitution of GelMA is optimal for wound dressings. Scanning electron microscopy revealed a uniform pore size, aiding inflammatory exudate removal. The Cur/ADP GelMA hydrogel exhibited strong adhesion, stability, and antibacterial activity, reducing E. coli and S. aureus proliferation by 85% and 72%, respectively. Hemostatic effects were observed, with blood loss reduced to 238 ± 23 mg compared to 559 ± 18 mg in the untreated group. The ELISA results showed reduced pro-inflammatory cytokines (TNF-α, IL-1β, IL-6) and increased IL-10. In vivo studies demonstrated 98% wound closure by day 14, enhanced granulation tissue formation, and a 70% thicker epidermis compared to controls. Mechanistically, ADP accelerates platelet activation and clot formation, while Cur modulates the inflammatory microenvironment, enabling synergistic hemostasis and immune regulation, thus promoting accelerated wound healing.

Gels doi: 10.3390/gels12060455

Authors: Jingwei Zhang Aolin Zhang Jia Li

Magnesium phosphate cement (MPC) shows great potential for complex underground environments due to its rapid-hardening and early-strength properties. However, its large-scale application is hindered by several drawbacks, including high hydration heat, rapid setting, and insufficient long-term durability. To address these limitations, this study developed a novel MPC grouting material modified with steel slag (SS) and redispersible latex powder (LP). We systematically investigated the workability, mechanical properties, durability, and microstructural evolution of this modified system. Results indicate that incorporating SS and LP decreases both the fluidity and setting time of the grout. An optimal SS dosage accelerates reaction kinetics and raises the peak hydration temperature. Conversely, the LP-induced polymer film suppresses the overall temperature rise, delaying the first exothermic peak and advancing the second. The incorporation of 5% steel slag increased the 28-day compressive strength of the MPC to 54.86 MPa. Building on this, the combined addition of 0.15% latex powder further elevated the strength to 58.82 MPa. Microstructural and pore analyses confirmed that the steel slag enhanced interfacial bonding through physical filling and the formation of calcium phosphate crystals. Meanwhile, the latex powder formed a continuous polymer film, which tightly wrapped and bridged the hydration products and unreacted particles. This synergistic mechanism effectively sealed the capillary pores and reduced the proportion of harmful pores by 15.99% compared to the control group. Consequently, the densified MPC matrix laid a solid microstructural foundation for the material’s excellent durability. It offers reliable, high-performance material for seepage control and strata reinforcement in complex environments.

Gels doi: 10.3390/gels12060454

Authors: Olga Kammona Evgenia Tsanaktsidou

Hydrogels are three-dimensional (3D) hydrophilic polymer networks characterized by increased water content (>90%) that have arisen as extremely versatile biomaterials for tissue engineering (TE) applications (e [...]

Gels doi: 10.3390/gels12050453

Authors: Xin Hu Jingyu Wang Haijin Tang Xinlian Su Lifang Zou Baocai Xu

This study investigated the effects of curdlan (CUR) on the structural stability and thermal processing properties of Pleurotus eryngii mycelium–soy protein isolate–cassava starch gels used as bio-ink scaffolds for 4D-printed meat analogs. Bio-inks containing different CUR concentrations (0–5%, w/w) were prepared, and their rheological properties, 3D printability, microstructure, and water distribution were systematically evaluated. The fermented meat analogs were then subjected to steaming and baking to assess cooking loss, dimensional shrinkage, and textural properties. The results showed that CUR significantly increased the yield stress and structural recovery of the bio-inks while maintaining high height retention (>87%), thereby providing a favorable scaffold for mycelial growth and subsequent product formation. During thermal processing, CUR effectively mitigated structural collapse, which may be attributed to its heat-induced thermally irreversible gelation and the formation of an internal supporting network that resisted matrix contraction and dehydration. In particular, the addition of 5% CUR reduced cooking loss from 12.83% to 7.35% during steaming and from 42.52% to 38.59% during baking, while reducing shrinkage to 9.29% and 18.00%, respectively. In addition, hardness, springiness, and chewiness were significantly improved after cooking. Overall, CUR functioned not only as a rheological modifier for extrusion printing but also as a heat-activated internal supporting network during cooking, owing to its thermally irreversible gelation.

Gels doi: 10.3390/gels12050452

Authors: Yunxiang Zheng Yonghan Wang Mengmeng Wang Xingzhou Wen Chunxiao Zhang Xiangpeng Wang

The development of high-performance adsorbents for treating dye-laden wastewater necessitates a deep understanding of structure–property relationships. This study presents a systematic investigation into the role of carbon material dimensionality (0D biochar, BC; 1D carbon nanotubes, CNT; 2D graphene oxide, GO) in modulating the properties of a dual physically crosslinked sodium alginate/polyacrylamide (SA/PAM) hydrogel for methylene blue (MB) adsorption. A series of composite hydrogels was fabricated via a sequential physical crosslinking strategy. Comprehensive characterization confirmed the successful incorporation and dispersion of carbon materials within the dual network. The three hydrogels showed good mechanical properties. Under the conditions of 25 °C, an initial MB concentration of 100 mg/L, and pH 10–11, the incorporation of carbon materials enhanced the adsorption capacity, with maximum adsorption capacities of 411.5, 410.6, and 422.8 mg/g for BC-H, GO-H, and CNT-H, respectively. Coexisting constituents in real water samples reduce adsorption capacity via competitive adsorption and interfacial interference. After five consecutive adsorption–desorption cycles, the adsorption capacities of BC-H, GO-H, and CNT-H decreased to 57.7%, 67.2%, and 61.7% of their initial values, respectively. Adsorption isotherm and kinetic studies revealed that the process followed the Langmuir model and pseudo-second-order kinetics, indicative of monolayer chemisorption. Mechanistic analysis identified synergistic contributions from electrostatic attraction, π-π stacking, and physical entrapment. Physical structural changes and chemical site occupation are the main reasons for the decrease in the adsorption performance of hydrogels during cyclic use. This work provides a rational design strategy for advanced adsorbents and a theoretical foundation for efficient dye wastewater remediation.

Gels doi: 10.3390/gels12050451

Authors: Gyunhee Cho Jongkuk Ko Yunwoo Lee

Micro/nanorobotics is emerging as a promising biomedical technology because of its precision, minimal invasiveness, multifunctionality, and potential to mitigate systemic adverse effects. At these ultraminiaturized scales, unique physical constraints necessitate design principles and actuation strategies distinct from those of conventional robotic systems, making material choice, structural design, propulsion mechanisms, and fabrication methods central to overall performance. In this review, we examine recent trends in micro/nanorobot development, with particular emphasis on the advantages of employing hydrogels and the current technical limitations associated with their use. Magnetic, chemical, acoustic, optical, and biohybrid propulsion strategies are comparatively analyzed, together with the material requirements and biological compatibility associated with each approach. Representative applications in drug delivery, tissue regeneration, and cancer therapy are further discussed to highlight the broad medical potential of these systems. Finally, remaining challenges related to material limitations, actuation efficiency, biocompatibility, and manufacturing scalability are identified, and future directions toward clinical translation and practical deployment are outlined. Overall, this review provides an integrated perspective on how hydrogel properties, actuation physics, fabrication strategies, and translational considerations collectively shape the development of more adaptive, biocompatible, and clinically relevant microrobotic systems.

Gels doi: 10.3390/gels12050450

Authors: David Pawłowski Kinga Słomska Jakub Telszewski Marcel Hubert Pilarski Kamil Klimkowski Julia Witkowska Elżbieta Jankowska

Radiotherapy remains one of the main pillars of cancer treatment and is used in more than half of all oncological patients. Despite continuous technological improvements, ionizing radiation inevitably causes damage to surrounding healthy tissues, leading to acute and chronic complications affecting multiple organs, including the skin, mucosa, heart, lungs, bones and gastrointestinal tract. Radiation-induced injuries significantly impair patients’ quality of life, limit therapeutic doses, and represent a major unmet clinical challenge. Hydrogels have emerged as promising biomaterials for managing radiation-induced damage due to their high content of water, tunable mechanics, and ability to mimic the extracellular matrix. Recent innovations have introduced functional systems, including stimuli-responsive, injectable, and bioactive hydrogels, capable of delivering antioxidants, growth factors, or living cells. Unlike traditional material-based reviews, this work proposes a novel classification framework based on the hydrogel’s mechanism of action within the pathophysiology of radiation injury. We evaluate how specific designs, such as ROS-scavenging matrices, barrier-forming injectable shields, and bioactive delivery vehicles, address distinct phases of inflammation and fibrosis. By providing a comprehensive overview of radiation-induced injuries across different organs, this review summarizes current hydrogel-based strategies for both prevention and therapy. We highlight the potential of these mechanistically aligned systems to protect healthy tissues, suppress chronic inflammation, and promote effective tissue regeneration.

Gels doi: 10.3390/gels12050449

Authors: Zhizhou Zhang

Machine learning (ML) is reshaping the design and deployment of conductive hydrogel biosensors for wearable health monitoring by coupling material chemistry with scalable manufacturing and robust signal analytics. Persistent bottlenecks include hydration stability (dehydration and freezing), data scarcity, device variability, and model transfer across users and environments. Recent advances demonstrate ML-enabled gains across electrochemical, mechanical, optical, and multimodal transduction, improving feature extraction, drift compensation, and generalization in applications spanning electrophysiology, sweat chemistry, and soft tactile sensing. On the material side, polymer informatics and graph-based representations are emerging to predict gel properties and guide composition/structure selection. In analytics, physics-informed models are enhancing impedance and voltammetry interpretation and reliability. Building on these trends, this review outlines standards for dataset curation (metadata on ionic milieu, temperature, humidity history, and mechanical loading) and strategies for cross-user and domain generalization. This review closes with actionable design guidelines for standardization, real-time analytics, and the clinical translation of hydrogel wearables.

Gels doi: 10.3390/gels12050448

Authors: Hongyu Zheng Shikui Wu Yujie Liu Yuzhu Zhang Yushu Xing Jianye Wang Xin Yue Lijun Sun Xiao Li Ying Zhang Jiannan Ma Xiaoli Du Yan Xue Juan Yu Huiwen Zhang Huanyun Wang

This study aimed to develop antibacterial polyphenol–chitosan hydrogel dressings and, more importantly, to compare how three structurally distinct low-cost natural polyphenols—protocatechuic acid (PCA), gallic acid (GA), and tannic acid (TA)—regulate hydrogel performance within the same chitosan platform. PCA, GA, and TA were incorporated into chitosan to obtain the corresponding hydrogels, denoted CS-PCA, CS-GA, and CS-TA. Scanning electron microscopy confirmed that all formulations possessed a three-dimensional porous network. Rheological characterization revealed favorable viscoelastic behavior for all polyphenol-containing hydrogels, with CS-TA showing the highest mechanical strength in the present system. The hydrogels also exhibited pH-responsive swelling, good tissue adhesion, self-healing ability, and injectability. In vitro antibacterial assays demonstrated activity against both Gram-positive and Gram-negative microorganisms, with CS-TA showing the most favorable overall antibacterial performance under the tested conditions. In a rat full-thickness wound model, hydrogel treatment accelerated wound closure, while H&E staining indicated enhanced granulation tissue formation, collagen deposition, and reduced inflammatory cell infiltration. Collectively, these findings support the use of polyphenol–chitosan composite hydrogels as promising wound-dressing candidates and highlight the value of a side-by-side comparison of PCA, GA, and TA for understanding structure–property–function relationships in this class of materials.

Gels doi: 10.3390/gels12050447

Authors: Khair Ul Wara Muhammad Hasan Masrur Rana Talha Khalid Hadiya Malik Komal Tariq Abdul Alber Sang-Eun Song Jawad Hussain Saad Abdullah

Ultrasound coupling technology is pivotal to ensuring high-quality diagnostic imaging, yet conventional water-based gels face persistent challenges, including acoustic impedance mismatch, air-bubble formation, dehydration, messiness, and cross-contamination risks. This review presents a comprehensive analysis of the evolution, materials science, and clinical performance of ultrasound gel pads, an advanced alternative engineered for superior acoustic transmission, hygiene, and patient comfort. Historical progression from early coupling agents to modern polymeric and hydrogel-based pads is traced, highlighting breakthroughs such as bilayer hydrogels, nanocomposite reinforcements, metamaterial-inspired designs, and patient-specific 3D-printed pads. Comparative evaluations demonstrate that gel pads, particularly those integrating nanotechnology, rival but often outperform traditional gels in transmission efficiency, near-field resolution, and adaptability to complex anatomical surfaces, while offering reusability and reduced environmental impact. For instance, solid gel pads achieved 92.3% stone disintegration, compared with 45.5% for semi-liquid gel, in ESWL phantom studies (p < 0.001). Materials, including polyacrylamide, silicone, and advanced hydrogels, are analyzed for mechanical properties, biocompatibility, and sustainability, with emphasis on biodegradable and locally sourced alternatives. Manufacturing innovations ranging from continuous casting to additive manufacturing enable customization, functional integration, and scalable production, although cost, supply chain stability, and regulatory compliance remain critical barriers. By uniting advances in materials engineering, nanotechnology, and precision manufacturing, ultrasound gel pads have demonstrated strong potential to advance coupling media for diagnostic, therapeutic, and wearable ultrasound applications, enabling higher diagnostic accuracy, streamlined workflows, and patient-centered care across diverse clinical and resource-limited settings.

Gels doi: 10.3390/gels12050446

Authors: Yuhao Xia Fengfeng Xiao Jun Wang Jingping Liu Meng Li Yuanwei Sun

Gel plugging agents are key drilling fluid additives for maintaining wellbore stability. However, the downhole ultra-high-temperature, high-salinity environments, and developed micro-fractures in deep and ultra-deep wells pose severe challenges to the performance of gel plugging agents. To address this problem, this paper presents the preparation of a nano-micron gel plugging agent with a core–shell structure, denoted as LMS, suitable for high-temperature and high-salinity water-based drilling fluids. LMS was synthesized via emulsion polymerization, using a styrene–sodium p-styrenesulfonate copolymer as the core and 2-acrylamido-2-methylpropanesulfonic acid and methacryloyloxyethyltrimethyl ammonium chloride as the shell-modifying monomers. LMS was characterized by infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, and particle size analysis, confirming that LMS met the design expectations. Experimental results showed that after aging at 220 °C for 16 h under saturated-salt conditions, the filtration loss of the drilling fluid with 3 wt% LMS was 10.4 mL, a reduction of 57.4% compared to the base mud. Meanwhile, LMS exhibited good plugging performance in microporous membrane tests and sand bed tests. After aging at 220 °C for 16 h under saturated-salt conditions, the core plugging rate reached 95.4%. LMS can not only adsorb onto clay surfaces to increase the thickness of the hydration film, enhancing drilling fluid stability, but can also synergistically build a filter cake with clay particles to plug nano-micron pores, preventing drilling fluid infiltration into the formation. This paper provides a preparation method for a high-temperature- and high-salinity-resistant gel plugging agent with excellent plugging effects, which is expected to support safe and efficient drilling in deep and ultra-deep formations.

Gels doi: 10.3390/gels12050445

Authors: Jianbing Li Liwei Niu

To improve the effectiveness of sulfonated polyacrylamide soft microgels (SMGs) in deep profile control, this study investigated a surfactant-assisted regulation strategy based on surfactant uptake and surfactant–microgel association. The uptake behavior of a hydroxysulfobetaine surfactant by SMGs was characterized, and the resulting changes in swelling, frequency-dependent elastic response, electrostatic stabilization, shear resistance, and long-distance transport were evaluated. The surfactant uptake process was well described by pseudo-second-order kinetics and a Langmuir-type saturation model, while FTIR and XPS analyses provided spectroscopic evidence for surfactant association with SMGs, especially at the particle surface. Compared with the SMG system, surfactant addition mildly reduced the swollen median size (D50) at 15 d from 15.72 to 14.90 μm, and the corresponding swelling ratio decreased slightly but remained above 6.45. The S/SMG system also showed a larger magnitude of negative zeta potential, maintaining a value of −38.5 mV after 60 d compared with −32.1 mV for the SMG system, and generally better shear resistance, with particle size retention 0.8–3.8 percentage points higher over 0–7 d of swelling. Serial core-flooding experiments showed improved deep transport behavior. Although the SMG system produced slightly higher injection pressure below 2.4 m, the S/SMG system maintained a slightly higher pressure response beyond this distance. These results demonstrate that surfactant uptake and surface/network association regulate SMG physicochemical properties, thereby improving their transport and deep profile-control performance.

Gels doi: 10.3390/gels12050443

Authors: Kao Wu Zihan Yu Zixuan Yang Yingjie Ding Hong Qian Ying Kuang Man Xiao Fatang Jiang Bo Peng

Airborne particulate matter pollution has posed severe threats to public health, while conventional air filtration materials suffer from non-biodegradability and poor structural stability. Herein, a series of eco-friendly konjac glucomannan/sodium alginate (KGM/SA) composite aerogels reinforced by silk microfibers (SFs) were fabricated via freeze-drying. The extracted SF had a concentrated diameter distribution of 500 nm, with a well-preserved crystalline structure and the β-sheet secondary structure of natural silk. Results demonstrated that SF incorporation effectively regulated the pore structure, with reduced pore sizes, and an optimized uniform and compact cobweb-like porous network was achieved at 70% SF addition (KSSF70), with a maximum compressive stress of 78.89 kPa at 60% strain, a PM10 filtration efficiency of 99.8%, and a PM2.5 efficiency of 71.2%. Also, the removal efficiency of particles < 0.3 μm was boosted from 26% to 47% compared with the KGM/SA aerogel. Furthermore, the calculated quality factor met mainstream commercial standards. These findings guided SF use in improving the pore structure of biomass aerogels for enhanced air filtration performance.

Gels doi: 10.3390/gels12050444

Authors: Domenico Mammolenti Domenico Gabriele Francesca Romana Lupi Noemi Baldino Patrizia Formoso

Biphasic systems able to effectively release bioactive molecules along the gastrointestinal tract (GIT) are receiving growing interest. In this work, emulgels structured with citrus fiber, a digestion-resistant structuring agent, were produced using two types of edible oils (Miglyol® 812 N and rice oil). Samples with 3% w/w of fiber were loaded with curcumin. The rheology of emulgels, reference hydrogels, and oil phases was studied. Complex modulus (G*) and viscosity (η) increased with increasing fiber fraction, whereas the phase angle (δ) was fiber fraction-independent (p < 0.05). Dynamic and flow behaviors were modeled using weak gel model and modified Cross model, respectively. Samples with rice oil were more consistent and viscous than samples with Miglyol® 812 N because of the higher G* and η of rice oil. Curcumin does not affect the rheology of oils, whereas it modifies the emulgel behavior. In emulgels, curcumin does not change (p < 0.005) both weak gel parameters. Gel strength (A) was 750 ± 40 Pa sz again 760 ± 40 Pa sz and 597 ± 2 Pa sz again 604 ± 4 Pa sz for the system with rice oil and Miglyol® 812 N, respectively, and network extension (n) resulted to be 14.13 ± 0.03 for all samples. Curcumin slightly increases the phase angle δ, 5.83 ± 0.09° again 7.0 ± 0.2° and 5.5 ± 0.1° again 7.10 ± 0.08° for the system with rice oil and Miglyol® 812 N, respectively. This suggests a reduction in the structure of the fiber network. Curcumin has an oil-dependent influence on the zero-shear-rate viscosity (µ0) and on the time constant (m), while it does not affect the shear-thinning index (n), which resulted to be statistically independent of all systems (p < 0.05) yielding an average value of 1.616 ± 0.007. According to in vitro release studies, the percentage of cumulative released curcumin at 24 h was 15 ± 1% for emulgel with Miglyol® 812 N, whereas for the sample with rice oil, it was 18 ± 1%. Overall, results suggest the attractiveness of these systems for potential applications in the sustained oral release of curcumin.

Gels doi: 10.3390/gels12050442

Authors: Guofan Zeng Jiaqi Zhu Zehong Wu Yihan Qiu Mingcen Weng

Polyvinyl alcohol (PVA)-based hydrogels suffer from insufficient mechanical strength, while aramid nanofibers (ANF) have intrinsic insulation that limits their sensing applications, and the synergistic effect of composite fillers remains underexplored. This study aims to develop a multifunctional PVA/ANF/NaCl composite organohydrogel for high-performance flexible sensors. The gel was fabricated via freeze–thaw crosslinking, solvent exchange and NaCl impregnation, with systematic investigations of its microstructure, mechanical, electrical and multifunctional sensing properties, and a corresponding triboelectric nanogenerator (TENG) and self-powered handwriting recognition system were constructed. Results show that 2% ANF significantly enhances the gel’s mechanical performance, 0.5 M NaCl achieves optimal mechanical-electrical balance, the gel-based sensor exhibits excellent distance, pressure and strain sensing with high cyclic stability, the TENG delivers stable electrical output, and the recognition system achieves 95% accuracy on the test set. This work provides a new material and design strategy for advanced flexible electronic devices.

Gels doi: 10.3390/gels12050441

Authors: Mengxiao Wang Jia Yang Gang Qin Qiang Chen

Flexible supercapacitors (SCs) have attracted considerable attention for wearable electronics, and developing high-performance electrolytes is critical for their practical application. While hydrogels have been widely investigated as solid electrolytes, studies on double-network (DN) hydrogel electrolytes specifically addressing the electrode–electrolyte interface stability under mechanical deformation remain relatively scarce. A major obstacle is maintaining a stable electrode–electrolyte interface under large mechanical deformation. Drawing inspiration from the mucus of a snail, which effectively adheres to various surfaces in challenging conditions, we present a self-healing xanthan gum/hydrophobically associated polyacrylamide/NaCl (XG/HPAAm/NaCl) hydrogel polymer electrolyte (HPE) that facilitates the creation of flexible SCs with improved mechanical and electrochemical properties. The optimized 2 wt% XG/HPAAm/0.4 M NaCl DN HPE exhibits a high ionic conductivity of 4.0 S/m, a tensile strength of 0.43 MPa, and an elongation at break of 11.7 mm/mm, along with a high adhesive energy of 254.7 J/m2. The tough HPE was coated with a mixed adhesive of 502 cyanoacrylate glue and triethyl citrate (TEC) to create a surface coating resembling “mucus”, onto which activated carbon (AC)-modified carbon cloth (CC) electrodes (CC/AC) were affixed on both sides to construct the flexible SCs. Investigations into the HPE’s characteristics and the SCs’ electrochemical performance at various bending angles reveal that the “mucus-coating” HPE exhibits strong electrode adhesion and significantly improved electrochemical performance. The assembled flexible SC delivers a high specific capacitance of 249.3 F/g at 0.30 A/g, retains 73.4% of its initial capacitance after 20,000 cycles, and maintains 86.9% capacitance retention under 180° bending, outperforming SCs assembled with original HPEs in both performance and stability. This approach provides a versatile method for improving the interfacial properties between electrodes and HPEs, paving the way for innovative applications in robust, self-healing, and flexible devices.

Gels doi: 10.3390/gels12050440

Authors: Zhixuan Yang Shuailin Li Youjia Yang Jiawei Yang Ruiying Zhang Jianguo Li Bin Chen

High-performance flexible electronics require soft materials that combine mechanical robustness with efficient ionic conduction. In conventional ionogels, however, these requirements often conflict: dense networks improve strength but reduce the free volume and mobility needed for ion transport. This review provides a critical overview of recent progress in cellulose-based ionogels, with emphasis on design principles for decoupling mechanical and conductive properties. We discuss how cellulose precursors, crosslinking architectures (hydrogen bonding, covalent networks, and metal-ion coordination), and processing histories determine gel structure and mechanical integrity. We then highlight strategies that mitigate the trade-off, including precursor engineering, phase-separated networks, double-network architectures, crystallization-induced reorganization, and anisotropic assembly. Representative applications in flexible sensors, flexible energy-storage devices, and soft actuators are also summarized. This review offers a practical framework for designing cellulose-based soft functional materials with robust mechanics and sustained ionic conductivity.

Gels doi: 10.3390/gels12050439

Authors: Yuquan Cao Ruliang Li Zikang Chen Miao Liu Yumin Duan Shuai Li Zhi Li

Facing the increasingly severe energy challenges and environmental problems, the development of thermally stable, lightweight, and thermal insulating materials is critical. Herein, we report an organic-inorganic composite strategy combined with a high-temperature carbonization step to fabricate aerogel-containing composites synergistically reinforced with chopped glass fibers and hollow glass microspheres. By systematically varying the ratio of acrylic emulsion to potassium silicate solution, we investigated the effects on the forming behavior, microstructure, hydrophobicity, thermal stability, and thermal insulation performance. Increasing the acrylic emulsion fraction substantially enhanced hydrophobicity, yielding a maximum water contact angle of 129.3°. Concurrently, the apparent density decreased from 0.18 g/cm3 to 0.09 g/cm3 and the thermal conductivity dropped from 57.9 mW/(m·K) to 29.0 mW/(m·K). Mechanical testing revealed that the compressive Young’s modulus decreased with increasing acrylic content, from 3.6 MPa for the purely inorganic sample to 0.55 MPa at 70% acrylic content, reflecting a trade-off between stiffness and organic-derived porosity. Microstructural characterization revealed a hierarchical porous network in which uniformly dispersed hollow glass microspheres and the aerogel-derived silica network form an efficient thermal barrier system. Thermogravimetric analysis demonstrated excellent thermal stability, with total weight loss below 5% up to 800 °C. Infrared thermography analysis showed that, after unilateral heating at 300 °C and 400 °C for 10 min, the backside surface temperature of the composites decreased as the acrylic emulsion content increased. At 300 °C, the temperature decreased from 176.1 °C for AP-1 to 151.0 °C for AP-4, while at 400 °C, it decreased from 228.5 °C to 199.3 °C. These results indicate that the composites exhibit effective thermal insulation and maintain structural stability under high-temperature exposure. Taken together, this facile and scalable approach yields these aerogel-containing composites that combine low density, low thermal conductivity, robust structural integrity, and good environmental resistance, as evidenced by a water contact angle of 129.3°, making them promising candidates for aerospace, building, and industrial high-temperature insulation applications.

Gels doi: 10.3390/gels12050438

Authors: Yangyang Chen Ying Miao Rui Huo Minjun Sun Jingyu Xie Meili Zhang

Oat starch, β-glucan, and protein are the primary components in oats with high nutritional value, and the interactions among these three constituents markedly influence the starch properties. High hydrostatic pressure (HHP), recognized as a non-thermal processing technique, is primarily employed for the modification of starch and protein in food processing applications. This study aimed to elucidate the interactions among oat β-glucan, protein, and oat starch under 300 MPa HHP treatment and their effects on starch properties. The results showed that at ambient pressure, β-glucan and protein mainly restricted starch swelling and gelatinization through water competition, leading to reductions in pasting viscosity, gelatinization enthalpy, and relative crystallinity. In contrast, HHP treatment significantly enhanced the intermolecular interactions among the three components, thereby improving the freeze–thaw stability, gel elasticity, short-range ordered structure, and thermal stability of the composite system. The study demonstrates that HHP modifies the physicochemical properties of starch by intensifying interactions among its components, providing a theoretical basis and strategy for the development of novel functional starch-based foods using HHP technology.

Gels doi: 10.3390/gels12050437

Authors: Julia C. Matros Katharina E. Wiebe-Ben Zakour Joana Witt Michael C. Hacker

Tissue engineering represents a central strategy in regenerative medicine to restore damaged or missing tissue through structural and functional replacement. In this study, a two-component bioink platform was developed based on amine–anhydride conjugation as a mild crosslinking reaction between synthetic anhydride-containing oligomers (oSMoMA-x) and natural biopolymers. The compatibility of the oligomers with different amine-containing biopolymers, including chitosan, gelatin, and hydrolyzed collagen peptides, was systematically evaluated. To improve cytocompatibility and enable controlled network formation, oSMoMA oligomers with varying anhydride contents were synthesized and characterized, allowing targeted tuning of material properties through comonomer composition. The resulting hydrogels were comparatively assessed with respect to their rheological and physicochemical properties. While hydrogel formation was achieved with all investigated biopolymers, gelatin-based systems exhibited the most favorable characteristics for bioink development. Two gelatin/oSMoMA bioink formulations with distinct gelation behavior were obtained by employing different base catalysts, enabling control over crosslinking kinetics and material properties. Cytocompatibility was comprehensively evaluated using viability assays, demonstrating enhanced metabolic activity of cells encapsulated in gelatin/oSMoMA-3.5 hydrogels compared to established reference systems, with sustained compatibility for up to seven days. Extrusion-based 3D bioprinting was performed using a modified printhead with integrated temperature control to maintain physiological conditions. The bioinks were successfully printed with embedded murine 3T3 fibroblasts, and post-printing analyses confirmed cell proliferation within the hydrogel constructs. Overall, the results demonstrate the broad compatibility of amin–anhydride-crosslinked oSMoMA systems with different biopolymers and highlight gelatin/oSMoMA bioinks as promising cytocompatible materials for stable 3D bioprinting applications in tissue engineering.

Gels doi: 10.3390/gels12050436

Authors: Simeng Ma Zhuanghong Wang Honghao Fan Hai He

Silk fibroin (SF)–polyphenol systems have emerged as a versatile class of gels and hydrogels in which supramolecular interactions and dynamic crosslinking regulate network formation, responsiveness, and multifunctional performance. Polyphenols interact with SF through hydrogen bonding, hydrophobic interactions, π–π stacking, metal coordination, and covalent crosslinking, thereby modulating conformational transitions, gelation behavior, structural stability, and interfacial functionality. These interaction mechanisms enable the development of SF–polyphenol gel systems with tunable mechanical properties, wet adhesion, antioxidant activity, self-healing capability, and stimuli responsiveness. This review summarizes recent advances in SF–polyphenol gels and hydrogels, with particular emphasis on molecular interaction mechanisms, gelation and fabrication strategies, responsive behaviors, and structure–property relationships. Representative preparation approaches, including solution blending, electrospinning, impregnation–adsorption, enzymatic crosslinking, metal–phenolic coordination, and photo-initiated processing, are systematically discussed in relation to their effects on network architecture and functional output. The responsive behaviors of these systems under pH, redox, electrical, thermal, and optical stimuli are also analyzed from the perspective of dynamic gel networks and adaptive material design. Emerging applications of SF–polyphenol gels in bioadhesives, delivery platforms, flexible bioelectronics, wound-related materials, and sustainable functional systems are highlighted. Current limitations associated with polyphenol instability, formulation sensitivity, reproducibility, and scale-up are critically discussed, together with future opportunities for predictive design of gel-based natural polymer systems. This review provides a comprehensive framework for understanding SF–polyphenol gelation and for guiding the development of next-generation multifunctional gels and hydrogels.

Gels doi: 10.3390/gels12050435

Authors: Xuchun Yang Yafei Liu Fen He Chenlu Du Jingdi Zheng Desheng Zhou

In oil and gas development, the oil displacement efficiency of single surfactants is inherently constrained. While synergistic interactions between salt ions and surfactants can enhance displacement performance by modulating interfacial properties and wettability, the underlying mechanisms remain insufficiently understood. This study systematically investigated the synergistic effects of two monovalent salts (NaCl, KCl) and four surfactants through macroscopic characterization of interfacial property and microfluidic displacement experiments using microfluidic device with dead-end structures. The results show that salt type and concentration significantly influence interfacial dynamics. The four selected surfactants exhibit gel-like behavior through molecular self-assembly in aqueous solutions, and their synergistic interaction with salt ions enhances oil displacement efficiency by modulating interfacial characteristics. High-salinity solutions reduce interfacial tension, with CTAB exhibiting a concentration-dependent decrease, while NP-10 behavior is governed by both surfactant and salt concentrations. The presence of Na+ generally resulted in lower IFT, improved interfacial viscoelasticity, and more favorable wettability alteration compared to K+. One-way analysis of variance confirmed that salt type is the main factor affecting recovery rate (p < 0.05). Notably, 0.2% CTAB+50,000 mg/L NaCl combination achieved the highest recovery rate owing to an optimal balance between interfacial adsorption, film viscoelasticity, and wettability alteration. This investigation elucidates the mechanisms driving surfactant–salt synergism and proposes an optimized surfactant and salt formulation to enhance oil recovery through tailored interfacial properties.

Gels doi: 10.3390/gels12050434

Authors: José Benito Pelayo-Vázquez Daryl Rafael Osuna-Laveaga José Patricio Peña-Jaramillo Sergio Gómez-Salazar Edgar David Moreno-Medrano María Guadalupe Pérez-García

Ciprofloxacin (CIP) is a persistent fluoroquinolone antibiotic frequently detected in water bodies, and its efficient mineralization remains a challenge in wastewater treatment. In this work, iron oxide–chitosan macroporous nanocomposite hydrogels were developed as heterogeneous catalysts for the electro-Fenton degradation of CIP. The materials were synthesized via Pickering high internal phase emulsion templating, yielding monoliths with a three-dimensional interconnected porous structure, an average pore size of 18.9 ± 0.7 µm, a window size of 8.1 ± 0.7 µm, an openness degree of 39.6%, a specific surface area of 1.77 m2 g−1, an iron content of 64.2 mg g−1, and a crosslinking degree of 92.1%. The monoliths exhibited controlled swelling in aqueous medium at pH 3, with a gravimetric water uptake of 142.1 ± 2.3% and a volumetric swelling of 39.3 ± 1.2% at equilibrium. Iron oxide particles remained exposed on the porous surface, providing accessible catalytic sites, while the interconnected porosity favored reactant diffusion. Compared with direct anodic oxidation, which achieved 32% total organic carbon removal after 20 min, the heterogeneous electro-Fenton process using the synthesized monoliths as catalysts showed superior performance, reaching nearly 95% removal within 2 min and complete mineralization within 15 min. This enhanced performance was associated with higher hydroxyl radical generation (~3.5 µM) than that observed for anodic oxidation alone (~1.5 µM). These findings highlight the potential of biodegradable iron oxide–chitosan macroporous hydrogels as sustainable catalysts for antibiotic removal from water.

Gels doi: 10.3390/gels12050433

Authors: Sisi Wang Gang Wang Xuefei Liu Jinshun Bi Wenjun Xiao Degui Wang Mingqiang Liu Changsong Gao Ziqiang Xu Zhen Wang Yan Wu Abuduwayiti Aierken

Temperature/pH dual-responsive hydrogels are a class of smart materials capable of undergoing reversible structural or functional changes in response to temperature and pH stimuli. Owing to their remarkable dual-stimuli-responsive characteristics, these hydrogels have demonstrated significant potential in various biomedical applications, including drug delivery, tissue engineering, and diagnostics technologies, making them a prominent research focus. Although considerable progress has been made in recent years, a systematic summary of the preparation methods, structural design strategies and complex biomedical applications of these materials remains conspicuously absent. Consequently, this review aims to comprehensively examine the latest advancements in this field. First, the primary preparation methods of temperature/pH dual-responsive hydrogels, including chemical crosslinking, physical crosslinking, and hybrid crosslinking, are introduced and compared. Subsequently, the main structural design strategies, including microsphere, core–shell and layered structures, and their corresponding fabrication processes are systematically elucidated. Finally, the recent progress of temperature/pH dual-responsive hydrogels in biomedical applications is discussed, including drug delivery, cancer therapy, biosensing and diagnosis, tissue engineering and regenerative medicine, as well as wound healing. Based on the current research progress, this review also outlines the major challenges in the development of temperature/pH dual-responsive hydrogels, and presents perspectives on future research directions.

Gels doi: 10.3390/gels12050432

Authors: Sanja Knežević Marija Ivanović Snežana Nenadović Dorota Korte Swapna Mohanachandran Nair Sindhu Marijan Nečemer Miloš Nenadović

Aluminosilicate materials, known for their high strength, corrosion resistance, and thermal stability, are synthesized through the alkali activation of metakaolin, incorporating Sm2O3 to investigate the impact on their physicochemical properties. This study takes a look at the synthesis and physicochemical characterization of aluminosilicate gels doped with samarium(III)-oxide (Sm2O3), focusing on their potential as thermal insulators due to their enhanced thermal conductivity and absorption properties. Two samples with 1% and 5% Sm2O3 by weight were investigated, referred to as S1 and S2, respectively. Characterization techniques such as energy-dispersive X-ray fluorescence spectrometry (EDXRF), diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), scanning electron microscopy (SEM), and photothermal beam deflection (PBD) were employed for the physicochemical characterization of aluminosilicate materials. The structural analysis shows an integration of Sm2O3, which did not significantly affect the gel’s density or porosity but enhanced its thermal conductivity. This study shows the potential of Sm2O3-doped aluminosilicates in applications requiring improved thermal management and stability, positioning them as potentially suitable materials for insulation.

Gels doi: 10.3390/gels12050431

Authors: Cleny Villalva-Cañavi Alma Berenice Jasso-Salcedo Daniel Lardizabal-Gutierrez

The atypical proliferation of Sargassum (Sargassum spp.) in the tropical Atlantic and the Caribbean Sea over the past decade has triggered an unprecedented environmental and socioeconomic crisis along the Mexican coastline. Continuous beaching events of this macroalga on the Riviera Maya have caused coastal ecosystem degradation, severe impacts on the tourism sector, toxic gas emissions during decomposition, and high cleanup costs. To address this challenge, the valorization of Sargassum as a raw material for synthesizing functional materials represents a sustainable management strategy. In this study, a superabsorbent hydrogel was developed from Sargassum biomass (collected in Cancún, Quintana Roo, in 2025) using an innovative process that bypasses the conventional cellulose isolation step. The biomass was subjected to high-energy milling (15 and 30 min) to prepare Sargassum powder, which was subsequently carboxymethylated using monochloroacetic acid. This modified biomass was then crosslinked with citric acid, a process evaluated at three different citric acid/carboxymethylated Sargassum mass ratios. The hydrogel synthesized with the lowest crosslinking agent ratio achieved a maximum water absorption capacity of 1160 wt%, a value that exceeds the typical absorption capacities of 700–900% for biopolymer hydrogels. Successful material formation was confirmed by Fourier transform infrared spectroscopy (FTIR), which revealed the characteristic functional groups of CMC and the ester bonds formed during crosslinking. Additionally, scanning electron microscopy (SEM) analysis showed a well-defined porous structure with pore sizes ranging from 8.5 to 19.5 µm, which is essential for its high absorption performance. This study demonstrates the feasibility of producing high performance hydrogels from Sargassum through a simplified, cost-effective, and environmentally friendly process. These findings open a promising avenue for the integrated management of this problematic biomass, transforming it into value-added materials with potential applications in agriculture, hygiene, and environmental remediation.

Gels doi: 10.3390/gels12050430

Authors: Karina Ilona Hidas István Dalmadi Koppány László Majzinger Anna Visy Adrienn Varga-Tóth Csaba Németh Ildikó Csilla Nyulas-Zeke

Freeze–thaw cycles lead to undesirable gelation in egg yolk, which negatively affects its functional properties, restricting its application in the food industry. This study aimed to investigate whether enzymatic treatment can prevent the freeze-induced gelation of egg yolk, thereby maintaining its desirable quality attributes. Egg yolk samples were treated with an enzyme preparation (Biocatalysts Flavorpro™ 750MDP) at concentrations of 0.05, 0.3, and 0.5 w/w%, homogenized, and incubated at 40 °C for 120 min, followed by rapid cooling and freezing at −24 ± 1 °C for 60 d. Control samples without enzyme treatment were subjected to the same processing steps as the other samples. After thawing, all samples were analyzed for pH, color, rheological and thermophysical properties, turbidity and visual appearance. The results demonstrated that although enzymatic treatment and its combination with freezing significantly altered color, turbidity, rheological and thermophysical properties of egg yolk, it effectively inhibited freezing-induced gel formation, particularly at 0.3 w/w%. The parameters characterizing rheological behavior—yield stress, consistency coefficient, and flow behavior index—were preserved close to those of fresh yolk after the freeze–thaw process. These findings suggest that exopeptidase treatment is a promising approach for controlling freeze–thaw-induced gelation in egg yolk, supporting its wider use in frozen and processed egg products.

Gels doi: 10.3390/gels12050429

Authors: Gábor Kammerhofer Ákos Tamás Nagy Árpád Joób-Fancsaly György Szmirnov Ilona Szmirnova Dániel Végh Márton Kivovics György Szabó Zsolt Németh

Oral mucosal and periodontal diseases are commonly associated with persistent inflammation, oxidative stress, impaired wound healing, and reduced oral health-related quality of life. Nano-Bio Fusion (NBF) gingival gel is a bioadhesive nano-formulated oral gel containing propolis, vitamin C, and vitamin E, developed for local application under oral soft tissue conditions. This critical narrative review aimed to evaluate the currently available evidence regarding the clinical applications, safety profile, and therapeutic potential of NBF gel in oral soft tissue therapy. A structured non-systematic literature search was performed using PubMed, Embase, Cochrane Library, and Google Scholar, and 16 relevant studies were included. The available evidence suggests that NBF gel may provide clinical benefits as an adjunct to non-surgical periodontal therapy, with reported improvements in plaque and gingival indices, periodontal probing depth, clinical attachment level, wound healing, and pain-related outcomes. In addition, potential beneficial effects have been reported in oral surgery-related wound healing, alveolar osteitis, desquamative gingivitis, erosive lichen planus, and xerostomia-associated mucositis. Several studies reported outcomes comparable to conventional therapies, including chlorhexidine-based regimens and locally delivered antimicrobials; however, the evidence remains heterogeneous and limited. Furthermore, the proposed biological mechanisms, including antioxidant, antimicrobial, and tissue-modulating effects, are not yet fully supported by mechanistic or pharmacokinetic evidence. The currently available literature is limited by heterogeneity in study design, small sample sizes, short follow-up periods, and limited independent validation. Therefore, further well-designed, adequately powered randomized controlled trials with standardized methodologies are required to better define the clinical role of NBF gel in evidence-based oral soft tissue therapy.

Gels doi: 10.3390/gels12050428

Authors: Yunxiang Zheng Yonghan Wang Mengmeng Wang Chunxiao Zhang Xiangpeng Wang

The development of adsorbents with high adsorption capacity, easy separation, and good reusability is critical for the treatment of dye-contaminated wastewater. Herein, a novel magnetic composite hydrogel, P(AA-AM)/SA-BC-Fe3O4, was synthesized via free radical polymerization, integrating acrylic acid (AA), acrylamide (AM), sodium alginate (SA), biochar (BC), and magnetic Fe3O4 nanoparticles. The material was systematically characterized by FTIR, XRD, SEM, BET, and VSM, which confirmed the successful formation of a three-dimensional porous network with well-dispersed Fe3O4 nanoparticles and BC, endowing the hydrogel with superparamagnetic properties. The adsorption performance of the hydrogel towards methylene blue (MB) was evaluated under various conditions. The results demonstrated that the adsorption process followed the pseudo-second-order kinetic model and the Langmuir isotherm, indicating that chemisorption is an important mechanism in the monolayer adsorption process. The hydrogel exhibited excellent swelling properties and remarkable pH-dependent adsorption behavior, with optimal performance in weakly alkaline environments. Notably, the incorporation of BC enhanced the adsorption capacity, while Fe3O4 enabled rapid magnetic separation, with the adsorbent retaining approximately 77% of its initial capacity after five regeneration cycles. This work presents a promising strategy for constructing magnetic hydrogel adsorbents that synergistically combine high adsorption efficiency, facile separability, and good reusability for practical wastewater treatment applications.

Gels doi: 10.3390/gels12050427

Authors: A. M. Abdel-Mohsen Rasha M. Abdel-Rahman Katerina Skotnicova

Hydrogel scaffolds have emerged as a central platform in tissue engineering due to their ability to mimic the extracellular matrix and support cellular functions. Among natural polymers, chitin and its derivative chitosan have emerged as valuable candidates for hydrogel scaffold development because of their biodegradability, compatibility with living tissues, and inherent biological functionality; however, their distinct and complementary roles in hydrogel scaffold design are often insufficiently differentiated in the literature. This review provides a comprehensive and mechanism-driven analysis of chitin- and chitosan-based hydrogel scaffolds, emphasising how their molecular structure governs network formation, mechanical performance, and biological functionality. Chitin is highlighted primarily as a structurally robust and crystalline component suitable for reinforcement. In contrast, chitosan serves as a versatile, soluble, and chemically reactive matrix enabling various crosslinking and functionalization strategies. Recent advances in physical, ionic, and covalent crosslinking as well as composite scaffold engineering, biofunctionalization, and emerging fabrication approaches such as injectable systems and three-dimensional bioprinting are systematically examined. The relationships between scaffold architecture, degradation behaviour, and cellular responses are discussed in key tissue engineering applications, including bone, cartilage, skin, and nerve regeneration. Importantly, this review introduces a unified structure–property–function framework that distinguishes the roles of chitin and chitosan within hydrogel systems and links crosslinking mechanisms to application-specific performance requirements, an aspect not comprehensively addressed in previous studies. Current challenges related to mechanical limitations, material variability, and clinical translation are critically evaluated, and future perspectives for the rational design of next-generation biomimetic hydrogel scaffolds are proposed.

Gels doi: 10.3390/gels12050426

Authors: Carter Beamish Faraz Abounorinejad David Kim Ai Phuong Tong Harika Barri Chris Marx Daniel Lane Hugh McGregor Grace Laidlaw James Jeffries Ray Yeung Bruce Hinds Miqin Zhang Ryan L. McCarthy Kelly Stevens Avik Som

Chronic liver disease remains a major global health burden, with liver transplantation as the only definitive therapy despite severe limitations in donor availability, surgical morbidity, and patient eligibility. Although the liver has substantial intrinsic regenerative capacity, endogenous repair is often insufficient in chronic injury, cirrhosis, and acute-on-chronic liver failure. As a result, regenerative strategies that restore liver function without whole-organ replacement are increasingly pursued. This review examines controlled release biomaterial-based liver regeneration platforms, particularly those that utilize hydrogels and/or complementary nanoparticle systems, as clinically practical tools to enhance endogenous regeneration. We include discussion of both 3D scaffold-based and injectable hydrogels to enhance regeneration. Used as biological support and controlled release mixtures, they enable local retention, entrapping and controlling the release of regenerative cues including growth factors (HGF, EGF, etc.), nucleic acids for gene expression, stem cells or other cell populations, and conditioned extracellular vesicles, overcoming poor cell engraftment, short cytokine half-lives, and other limitations. Further, synthetic nanoparticles can structure release at the protein/molecular level as well as catalytically modulating oxidative stress and inflammation. Within the context of these systems, we structure the anatomical, engineering, and imaging considerations essential for the clinical translation of gel composite systems while highlighting remaining barriers to wider clinical adoption. Collectively, these advances position biomaterial-enabled regenerative therapies as a realistic alternative or bridge to donor restricted liver transplantation.

Gels doi: 10.3390/gels12050425

Authors: Jingchun Ma Shenghui Bi Xue Yang E Zhao Ying Zhou Chun Ye Yuanyuan Liu Qiujin Zhu

Protein-stabilized high-internal-phase Pickering gel-like emulsions (HIPGEs) have gained broad attention in the food industry and functional food sectors. Polyphenol–protein synergy is a common strategy to improve gel-like emulsion stability, yet issues such as insufficient interfacial viscosity persist, leading to poor long-term stability. Therefore, this study employed ovalbumin (OVA)-tea polyphenol (TP) as a composite model and introduced strongly negatively charged hyaluronic acid (HA) to construct a ternary Pickering gel-like emulsion with enhanced interfacial viscosity. We investigated the microstructure, physicochemical properties, stability mechanism, and simulated digestion behavior of the system. Results show that HA interacts with proteins and polyphenols via hydrogen bonding, strengthening the hydrogen-bond network and markedly improving gel-like emulsion stability. Moreover, HA stabilizes the oil–water interface by enhancing the viscoelasticity of the system. At 0.8% HA, centrifugal stability reached 99.52%, rheological properties were optimal, and droplets were more uniform and tightly packed. In vitro digestion revealed that 0.8% HA increased the final retention of lutein to 35.16% and reduced free fatty acid release to 0.31 μmol, demonstrating excellent protective and controlled-release potential. This study confirms that HA can significantly improve the stability and digestively controlled release of OVA-TP Pickering gel-like emulsions, providing theoretical support for polysaccharides in enhancing protein–polyphenol composite Pickering systems.

Gels doi: 10.3390/gels12050424

Authors: Peng Zhang Xiao Zhang Xiaobing Dai Shiyao Wei

Nano-SiO2-reinforced epoxy resin gel mortar (NERM) serves as an essential material for repairing and strengthening defective structures in civil engineering. This study developed a hybrid fiber-reinforced NERM (HF-NERM) by incorporating PVA–steel fiber, aiming to achieve superior mechanical properties, toughness, and bonding performance. This study systematically investigates the workability, mechanical properties, toughness, and bonding characteristics of HF-NERM, as well as their enhancement mechanisms characterized using scanning electron microscopy (SEM). Experimental results indicate that the slump of HF-NERM decreased significantly with increasing hybrid fiber content, and the regression coefficient of PVA fiber on slump was −86.7, while that of steel fiber was −4.5. The addition of hybrid fibers generally enhanced the mechanical properties. The optimal combination was 0.9% PVA fiber and 1.2% steel fiber, at which the flexural strength reached 11.56 MPa with an increase of 32.57%, splitting tensile strength reached 4.42 MPa with an increase of 20.1%, and interfacial bonding strength was improved by 9.8%. With the exception of splitting tensile strength, most mechanical properties initially increased and then decreased with increasing hybrid fiber content, indicating an optimal dosage. The hybrid fibers also enhanced the flexural toughness of HF-NERM; the toughness indices I5, I10 and I20 were increased by 20.99%, 24.12% and 65.83%, respectively, and the residual strength factors R5,10 and R10,20 were increased by 26.8% and 160.8%. The hybrid fibers also enhanced the flexural toughness of HF-NERM. Mechanistically, PVA fibers primarily contributed to preventing the development of micro-cracks, while steel fibers were the main contributors to resisting macro-cracks. SEM observations demonstrated that the failure modes of PVA fibers involved synergistic mechanisms, while those of steel fibers were relatively singular. Related enhancement mechanisms were discussed based on the experimental results. Finally, the results demonstrate that NERM could be effectively strengthened by adding an appropriate content of hybrid fibers. This study’s novelty lies in quantifying the individual and synergistic effects of PVA–steel fibers in the NERM system, establishing optimal dosage parameters, and revealing matrix–fiber interaction mechanisms specific to epoxy-based composites. The findings provide a reliable material design basis for high-performance repair mortars and offer practical guidance for extending the service life of aging civil engineering structures.

Gels doi: 10.3390/gels12050423

Authors: Xingxing Zhu Di Wu Juanjuan Wu Jinglong Zhao Yunhe Lian Yunkai Lv

To compare the structure and properties of hydroxypropyl starch/carrageenan blends with different amylose/amylopectin contents, two types of hydroxypropyl starch—a high-amylose type (amylose content > 70%) and a high-amylopectin type (amylopectin content > 95%)—were used. These starches had similar molecular weights, degrees of hydroxypropyl substitution, and other properties, differing only in their amylose and amylopectin contents. Each starch was blended with carrageenan via a solution blending method, and the resulting blends were systematically characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis, rheological tests, texture analysis, mechanical property tests, contact angle analysis, and UV-Vis spectrophotometry. The results showed that, upon blending with carrageenan, the hydroxypropyl starch transformed from a weak viscoelastic solution into an elastic, strong gel. FTIR and XRD analyses confirmed that the hydroxypropyl starch and carrageenan formed a homogeneous, compact, three-dimensional network via hydrogen bonding. This significantly enhanced the mechanical strength and stability of the blends. The influence of starch molecular structure on the blend system’s properties exhibited a pronounced state dependence. In the gel state, hydroxypropyl amylopectin effectively filled the carrageenan network due to its high swelling capacity, thereby improving the thermal stability and textural properties of the blends. However, in the film state, hydroxypropyl amylose with higher crystallinity and denser molecular packing contributed to superior tensile strength, hydrophobicity and light transmittance. Furthermore, the optimal mass ratio of hydroxypropyl starch to carrageenan was found to be in the range of 2:1 to 4:1. With this ratio, excessive cross-linking and poor compatibility could be avoided, resulting in improved mechanical performance, hydrophobicity, and light transmittance. This study reveals the relationship between starch molecular structure, system state and macroscopic properties, providing a theoretical basis for the rational design and regulation of the properties of hydroxypropyl starch/carrageenan blends.

Gels doi: 10.3390/gels12050421

Authors: Vyshnavi Tallapaneni Lavanya Mude Divya Pamu Vasanth Raj Palanimuthu Sai Varshini Magham Veera Venkata Satyanarayana Reddy Karri Madhukiran Parvathaneni

In the original publication [...]

Gels doi: 10.3390/gels12050422

Authors: Jorge U. Carmona Catalina López

Platelet-rich gel supernatants (PRGS) are increasingly used in veterinary medicine due to their regenerative and immunomodulatory properties; however, most studies focus on individual mediators and provide limited insight into their coordinated biological behavior. This study aimed to characterize the integrated inflammatory–regenerative signatures of bovine PRGS stored under different temperature conditions using a multivariate approach. Concentrations of transforming growth factor beta-1 (TGF-β1), tumor necrosis factor alpha (TNF-α), interleukin-2 (IL-2), and interleukin-6 (IL-6) were evaluated in PRGS samples from six clinically healthy cows stored at −80, −20, 4, 21, and 37 °C for up to 326 h. Data were standardized and explored using hierarchical clustering and heatmaps, and principal component analysis (PCA) based on area under the concentration–time curve (AUC) was used to integrate temporal behavior. Temperature-dependent multivariate signatures were identified, with frozen PRGS clustering separately from samples stored at moderate temperatures. The first two principal components explained 43.0% and 28.9% of the variance and defined an inflammatory–regenerative gradient contrasting TGF-β1/IL-2 versus TNF-α/IL-6 profiles. Linear mixed-effects modeling showed that PC1 was significantly affected by temperature and time (p < 0.001), whereas PC2 was influenced by temperature, time, and their interaction (p ≤ 0.048). Differences among temperatures were minimal at early time points but became more pronounced from 48 to 96 h onward, following a temperature gradient with higher values at moderate temperatures and lower values under frozen conditions. These findings indicate that storage temperature reshapes the integrated biological profile of PRGS, rather than merely preserving mediator composition.

Gels doi: 10.3390/gels12050420

Authors: Daniel Estevez Haritz Etxeberria Victoria Laura Barrio

CO2 methanation is considered a key process in achieving carbon neutrality. Expanding on our previous study of supercritically dried Ni-Al aerogels, this work compares two gel-based catalyst families prepared via two different routes—supercritically dried Ni impregnated Al aerogel-based catalysts and oven-dried one-pot Ni-Al xerogel-based catalysts—to assess how the synthesis route affects catalyst structure and CO2 methanation performance under light irradiation. The catalysts were subsequently characterized via different techniques, such as ICP-OES, N2 adsorption–desorption isotherms, XRD, H2-TPR, UV-vis DRS, XPS, and TEM. Catalytic activity was tested in a photoreactor at a range of temperatures from 300 °C to 450 °C and 10 bar pressure, and two different light sources were used (λ = 365 nm, λ = 470 nm). Both light sources enhanced catalytic activity in most cases; the xerogels with higher Ni loadings were the most active materials. These catalysts reached CO2 conversions and CH4 selectivities near 70% and 100%, respectively. The results indicate that drying gels is a promising method for synthesizing catalysts active in the Sabatier reaction, given the properties of the materials.

Gels doi: 10.3390/gels12050419

Authors: Md Murshed Bhuyan Kyungjun Lee Jae-Ho Jeong

The world’s current technical developments are mostly dependent on semiconductors. Even though traditional semiconductor materials are important, they have various disadvantages, especially when evaluated against polymer-based alternatives. Hydrogel-based semiconductors provide soft, ionically linked electronic interfaces by combining hydrated, mechanically compliant matrices with electrically active conjugated polymers and composites which can be applied in bioelectronic and thermoelectric generator/cells. Volumetric capacitances are normally in the range of 1–485 F·cm−3, demonstrating excellent ion storage, transport capabilities, and electron mobilities for hydrogel semiconductors spanning roughly 0.25 cm2/V·s (measured for n-type P(PyV)-H hydrogel). The fabrication techniques include additive free casting and room-temperature crosslinking, which lower energy input while maintaining electronic performance; typical systems maintain >80% of their conductivity after 103–104 mechanical cycles. This review study mainly focuses on the design, preparation, application, and prospects of gel/hydrogel-based semiconductors. It gives readers a thorough understanding of the basic ideas that underline their structure and operation. All things considered, this work is a useful tool for engineers and researchers looking to maximize the potential of gel-based semiconductors in next-generation electrical systems.

Gels doi: 10.3390/gels12050418

Authors: Deyu Kong Stanley Bryan Kurniawan Mengqing Huang Qiuhang Chen Jintao Liu

Hybrid MTMS–silica aerogels incorporating calcium silicate hydrate (C–S–H), the primary hydration product in cementitious systems, were synthesized via sol–gel processing followed by freeze-drying. The influence of C–S–H loading on pore structure, density, wettability, and thermal transport was investigated. The lowest thermal conductivity (0.068 W/m·K) and tap density (0.30 g/cm3) were obtained at 10% C–S–H loading (wM-CSH10), while the thermal conductivity increases to approximately 0.075–0.082 W/m·K at higher C–S–H content. All samples exhibit mesoporous structures with pore diameters in the range of 10–21 nm. Increasing C–S–H content progressively densified the network, reduced mesopore volume, and enhanced high-temperature mass retention up to 540 °C. FTIR analysis confirmed Si–O–Ca interfacial interactions, while nitrogen adsorption demonstrated persistent mesoporosity across all compositions. Thermal conductivity showed a positive correlation with density, indicating that bulk densification governs heat transport in the hybrid system. Beyond structural modification, the incorporation of C–S–H introduces chemical and microstructural features relevant to cement-based materials, suggesting potential compatibility with cementitious matrices. The results highlight the compositional trade-off between insulation efficiency and structural stability and demonstrate the potential of C–S–H-modified MTMS–silica aerogels for future integration into cement-based composites. These findings provide fundamental insight into their possible use in thermal insulation applications, such as building envelope systems (walls, façades, and roofs used for thermal insulation).

Gels doi: 10.3390/gels12050417

Authors: Yanjiao Wu Jiayue Chen Luyao Han Yiqiong Zhang Li Wei

The emergence of multifunctional wound dressings represents a significant transformation in the care of cutaneous tissue injuries, providing advanced solutions that surpass traditional dressings. This study is poised to fabricate multifunctional hydrogels through dual-dynamic cross-linking, integrating antibacterial and antioxidant properties, which are capable of accelerating wound healing while improving therapeutic outcomes. The hydrogel, which exhibits excellent adhesion, rapid self-healing ability, and on-demand removability, was synthesized employing poly(vinyl alcohol) (PVA)–borax as the backbone, followed by the incorporation of silk fibroin (SF), tannic acid (TA), and chitosan (CS). Total saponins of Panax notoginseng flower buds (PNF) with anti-inflammatory and angiogenic properties were loaded in porous structural materials yielding the PBCTS@PNF hydrogel. The prepared hydrogel exhibited outstanding antioxidant properties and cytocompatibility, along with favorable antibacterial capabilities, achieving inhibition rates of 84.30 ± 2.34% against Escherichia coli (E. coli) and 98.12 ± 0.76% against Staphylococcus aureus (S. aureus), respectively. Animal experiments demonstrated that PBCTS@PNF significantly reduced inflammation and promoted multidimensional tissue regeneration, encompassing re-epithelialization, neovascularization, and hair follicle regeneration, along with ordered collagen matrix organization, leading to substantially accelerated wound healing. The multifunctional PBCTS@PNF hydrogel provides a potent bioengineered therapeutic platform for wound healing management through the synergistic interplay among antibacterial, anti-inflammatory, and tissue regenerative functionalities.

Gels doi: 10.3390/gels12050416

Authors: Shijia Li Chao Wu Xiaojing Kang Ran Wang Qiang Cui Yuyu Zhang Mingkun Liu Beibei Dou Yang Liu Han Chen

This study reports the fabrication of Pickering emulsion gels stabilized by zein and curdlan (CU) and systematically elucidates the regulatory mechanisms of oil fraction and shearing parameters (temperature and duration) on their microstructure, mechanical properties, and stability. Results indicated that excessive oil content triggered pronounced flocculation and structural collapse, primarily attributed to insufficient interfacial coverage and compromised network continuity. An optimal dense network with superior cohesiveness was established at a shearing temperature of 60 °C, effectively entrapping oil droplets within the continuous phase. Furthermore, extending the shearing duration enhanced long-term stability by reducing droplet size, yielding a maximum oil binding capacity (OBC) of 78.9%. These emulsion gels exhibited remarkable stability against diverse environmental stressors, including thermal treatments, pH variations, and freeze-thaw cycles. This work expands the application of protein-polysaccharide complexes in food colloid science and provides a theoretical foundation for the development of novel low-fat food formulations based on emulsion gel systems.

Gels doi: 10.3390/gels12050415

Authors: Siraporn Mahakoat Sujaree Panomket Catheleeya Mekjaruskul Bunleu Sungthong

Kamala is a traditional Thai herbal knee poultice containing phenylbutenoid compounds with potent anti-inflammatory activity; however, its conventional form is inconvenient to use and exhibits variability in active compound content. This study aimed to develop a Kamala-based nanoemulsion gel to enhance dermal delivery and improve formulation consistency. Oils, surfactants, and co-surfactants were screened for their solubilization efficiency of (E)-1-(3,4-dimethoxyphenyl)butadiene (DMPBD) and (E)-4-(3′,4′-dimethoxyphenyl)but-3-en-1-ol (Compound D) using GC–MS. Pseudo-ternary phase diagrams were constructed to identify isotropic regions, and nanoemulsions with different Smix ratios were prepared by ultrasonication. Droplet size, polydispersity index (PDI), and short-term stability were evaluated. The optimized nanoemulsion was incorporated into a gel, and in vitro release was assessed using Franz diffusion cells. Coconut oil exhibited the highest solubilization capacity for both markers. A Tween 80:n-butanol system (2:1) generated the largest isotropic region (22.88%). The optimized formulation (Kamala extract:coconut oil:Smix:water = 1:2:50:47) showed droplet sizes of 77.92 ± 8.34 nm at 0 h and 130.89 ± 29.16 nm at 72 h, with PDI < 0.20. The nanoemulsion gel prepared with Aristoflex Velvet® (1% w/w) was transparent and physically stable. Franz diffusion studies demonstrated enhanced cumulative release and flux of Compound D in PBS containing 1% Tween 80. These findings indicate that the Kamala nanoemulsion gel is a promising topical delivery system for phenylbutenoid compounds in knee osteoarthritis.

Gels doi: 10.3390/gels12050414

Authors: Badr Bahloul Enis Ben Bnina Assia Hamdi Luis Castillo Henríquez Dhaou Baccar Nesrine Kalboussi Aïmen Abbassi Nathalie Mignet Guido Flamini José Roberto Vega-Baudrit

In the original publication [...]

Gels doi: 10.3390/gels12050413

Authors: Luohui Wang Jihang Hu Liyun Wang Xiaobo Xue Panrong Guo Youming Dong Fei Xiao Cheng Li Limin Guo

Hydrogels (HGs), three-dimensional cross-linked hydrophilic polymer networks, have emerged as a promising class of functional materials for sustainable agriculture due to their exceptional water retention capacity, responsiveness to environmental stimuli, and favorable biocompatibility. This review systematically summarizes the key functional properties of hydrogels and critically examines their multidimensional roles within agricultural systems. The major synergistic benefits of hydrogels are highlighted, including (1) improvement of soil physical structure, chemical properties, and the biological microenvironment, thereby facilitating soil remediation; (2) direct enhancement of seed germination, root development, and crop productivity when employed as soil amendments or seed-coating materials; (3) controlled and sustained release of water, nutrients (N, P, K, and trace elements), and pesticides, leading to significant improvements in resource use efficiency; (4) functional delivery of beneficial microorganisms, enabling precise regulation of their activity and efficacy; and (5) advancement of soilless cultivation technologies through the development of sophisticated hydrogel-based substrates. Furthermore, this review discusses the key challenges that currently limit large-scale agricultural implementation, including insufficient biodegradability, potential ecotoxicological risks, and techno-economic constraints. Finally, future research directions are proposed from an interdisciplinary perspective, emphasizing rational material design, performance optimization, and practical field application. This comprehensive review aims to provide systematic theoretical guidance and practical insights for the development and deployment of hydrogel-based technologies in sustainable agriculture.

Gels doi: 10.3390/gels12050412

Authors: Yu Wang Shuyu Song Qiuyan Liu Lihong Chen Weimin Liu Juan Wu Yu Cheng

Culture medium formulation influences mushroom yield and composition, but its effect on the properties of edible fungal protein remains unclear. To explore the functional and nutritional properties of proteins from Grifola frondosa (GF) fruiting bodies, the study examined the structural, interfacial, gelling, and digestive properties of GF proteins grown in four culture media. The four GF proteins obtained were labeled GFP1–GFP4, respectively. The β-turn content and intrinsic fluorescence in GFP1 increased by 41.48% and 36.45% (p < 0.05), respectively, compared to GFP4. GFP4 exhibited higher surface pressure at the air–water interface and lower interfacial force at the oil–water interface. In comparison with GFP4, the other GFPs showed a higher rate of interfacial film formation and greater film elasticity and strength. GFP2 had a minimum gelling concentration of 80 mg/mL, which is a 33.33% reduction from GFP4. The storage modulus (G′) of GFP1 was 58 times higher than that of GFP4 (10 Pa), indicating a significant increase in gel elasticity (p < 0.05). Additionally, compared to GFP4, GFP1 showed a 16.59% increase in total amino acid and a 6.82% increase in free amino group release (p < 0.05), although its digestibility decreased by 5.06% (p < 0.05). These results suggest that the formulation of the culture medium alters the structures and interfacial properties of GFPs, thereby impacting their functionalities and applications in food colloid-based products.

Gels doi: 10.3390/gels12050411

Authors: Hanyin Li Yi Meng Luohui Wang Yan Gao Youming Dong Liangdi Zhang Fei Xiao Hanmin Wang Cheng Li

Biomass represents a vital and sustainable resource for developing renewable materials with the potential to replace petroleum-based chemicals. Paulownia wood has high cellulose content and a loose wood structure, giving it natural advantages as a biomass material. Therefore, in this study, Paulownia wood was selected as a lignocellulosic feedstock. An integrated pretreatment process combining a deep eutectic solvent (DES) with an organic solvent was employed to efficiently remove lignin and hemicellulose, yielding cellulose-enriched residues. Subsequently, high-intensity ultrasonication was applied to convert the residues into cellulose nanofibers and nanocrystals. Using the extracted cellulose and nanocellulose, a dual-crosslinked network composite hydrogel was fabricated. The structural, mechanical, thermal, swelling, and conductive properties of the hydrogel were systematically investigated. The results show that, compared with the blank group hydrogel, the addition of nanocellulose increased the maximum tensile strength and tensile strain of the composite hydrogel by approximately 113% and 81%, respectively; meanwhile, the compressive strengths of the nanocellulose-based hydrogels (0.04575–0.09060 MPa) are higher than that of the blank group hydrogel (0.04235 MPa), confirming that the incorporation of nanocellulose significantly enhances the mechanical strength and elasticity of the hydrogel. The introduction of an AlCl3/ZnCl2 solvent system imparts appreciable electrical conductivity. Furthermore, the composite hydrogel maintains structural integrity after full swelling, indicating good dimensional stability and reusability. This work not only presents a green and efficient strategy for valorizing Paulownia biomass but also offers a novel design route for high-performance conductive hydrogel materials, highlighting their potential application in areas such as flexible electronics and energy storage.

Gels doi: 10.3390/gels12050410

Authors: Irina Negut Anita Ioana Visan

Chronic wounds remain a persistent clinical challenge, trapped in a cycle of inflammation, infection, and impaired healing. While traditional dressings offer basic protection, they fail to address the complex pathophysiology of non-healing wounds. This review critically examines cellulose-based hydrogels as next-generation therapeutic platforms, analyzing their structure–property relationships, biofunctionalization strategies, and stimuli-responsive capabilities. We synthesize recent advances in antimicrobial, anti-inflammatory, and pro-regenerative hydrogels, highlighting how cellulose’s inherent tunability enables precision wound management. Finally, we confront the translational barriers—including scalability, sterilization, and regulatory hurdles—that must be overcome to bridge the gap between promising biomaterial research and clinical reality. By integrating materials science with wound pathophysiology, this review provides a roadmap for developing clinically viable cellulose-based hydrogels.

Gels doi: 10.3390/gels12050409

Authors: Lina Zhang Tian Fang Changhai Liu Wenchang Wang Shiying Wang Zhidong Chen

This study reports a dual composition-interface engineering strategy for high-performance La1−xSrxCoO3/NiFe-LDH hierarchical heterojunction. Porous La1−xSrxCoO3 microspheres were synthesized through a gel route. Then it was used as an in situ–formed template to grow NiFe-LDH nanosheets. The hierarchical design inhibits nanosheet aggregation and ensures robust interfacial contact, mitigating the intrinsic instability of physical mixtures. The prepared composite displays superior OER performance in 1.0 M KOH, delivering an overpotential of 237.8 mV at 10 mA cm−2 and a Tafel slope of 85.06 mV dec−1. These values exceed those of the original samples and commercial RuO2 and the composite exhibits excellent long-term stability under harsh alkaline conditions. Complemented by DFT calculations, we further indicate that Sr doping coupled with the heterointerface induces substantial electronic structure reconstruction. This effectively switches the OER mechanism from conventional AEM to the thermodynamically more favorable LOM, overcoming the intrinsic scaling relation constraints of AEM.