Gels | May 2026 - Browse Articles

15 pages, 30080 KB

Open AccessArticle

Effect of Curdlan on the Structural Stability and Thermal Processing Properties of Mycelium-Based Gels Used in 4D-Printed Meat Analogs

by Xin Hu, Jingyu Wang, Haijin Tang, Xinlian Su, Lifang Zou and Baocai Xu

Gels 2026, 12(5), 453; https://doi.org/10.3390/gels12050453 - 21 May 2026

Viewed by 669

Abstract

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 [...] Read more.

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. Full article

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

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24 pages, 15836 KB

Open AccessArticle

Dual Physically Crosslinked Hydrogels via Multi-Dimensional Carbon Materials for Methylene Blue Adsorption

by Yunxiang Zheng, Yonghan Wang, Mengmeng Wang, Xingzhou Wen, Chunxiao Zhang and Xiangpeng Wang

Gels 2026, 12(5), 452; https://doi.org/10.3390/gels12050452 - 21 May 2026

Viewed by 583

Abstract

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 [...] Read more.

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. Full article

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35 pages, 3598 KB

Open AccessReview

Hydrogel-Based Micro/Nanorobots for Advanced Biomedical Applications

by Gyunhee Cho, Jongkuk Ko and Yunwoo Lee

Gels 2026, 12(5), 451; https://doi.org/10.3390/gels12050451 - 20 May 2026

Viewed by 792

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Functional Hydrogels for Soft Electronics and Robotic Applications)

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38 pages, 18858 KB

Open AccessEditor’s ChoiceReview

Hydrogels for Healing Radiation-Injured Tissues and Organs

by David Pawłowski, Kinga Słomska, Jakub Telszewski, Marcel Hubert Pilarski, Kamil Klimkowski, Julia Witkowska and Elżbieta Jankowska

Gels 2026, 12(5), 450; https://doi.org/10.3390/gels12050450 - 20 May 2026

Cited by 1 | Viewed by 1611

Abstract

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, [...] Read more.

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. Full article

(This article belongs to the Special Issue Recent Advances in Hydrogels: From Design to Wound Healing Application)

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35 pages, 31193 KB

Open AccessEditor’s ChoiceReview

Machine-Learning-Enabled Hydrogel Biosensors for Wearable Health Monitoring

by Zhizhou Zhang

Gels 2026, 12(5), 449; https://doi.org/10.3390/gels12050449 - 20 May 2026

Cited by 3 | Viewed by 1897

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Machine Learning in Hydrogel Design and Development)

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21 pages, 13187 KB

Open AccessArticle

Natural-Origin Bioadhesive Injectable Hydrogels Composed of Polyphenol and Chitosan with Antibacterial Activity for Wound Healing

by 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 and Huanyun Wang

Gels 2026, 12(5), 448; https://doi.org/10.3390/gels12050448 - 20 May 2026

Viewed by 724

Abstract

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 [...] Read more.

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. Full article

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

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54 pages, 43002 KB

Open AccessReview

Advancements in Ultrasound Gel Pad Technologies: Enhancing Diagnostic Precision, Procedural Efficiency, and Therapeutic Applications

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

Gels 2026, 12(5), 447; https://doi.org/10.3390/gels12050447 - 19 May 2026

Viewed by 1498

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Section Gel Applications)

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20 pages, 14555 KB

Open AccessArticle

Development and Performance Evaluation of a Core–Shell Structure Gel Plugging Agent for Ultra-High-Temperature and High-Salinity Water-Based Drilling Fluids

by Yuhao Xia, Fengfeng Xiao, Jun Wang, Jingping Liu, Meng Li and Yuanwei Sun

Gels 2026, 12(5), 446; https://doi.org/10.3390/gels12050446 - 19 May 2026

Viewed by 659

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Topic Polymer Gels for Oil Drilling and Enhanced Recovery)

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21 pages, 3041 KB

Open AccessArticle

Hydroxysulfobetaine Surfactant Uptake Regulates the Transport Behavior of Sulfonated Polyacrylamide Soft Microgels for Deep Profile Control

by Jianbing Li and Liwei Niu

Gels 2026, 12(5), 445; https://doi.org/10.3390/gels12050445 - 19 May 2026

Viewed by 349

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Topic Enhanced Oil Recovery Technologies, 4th Edition)

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28 pages, 6858 KB

Open AccessArticle

Structure–Function Relationship in Citrus-Fiber-Based Emulgels for Controlled Curcumin Delivery

by Domenico Mammolenti, Domenico Gabriele, Francesca Romana Lupi, Noemi Baldino and Patrizia Formoso

Gels 2026, 12(5), 444; https://doi.org/10.3390/gels12050444 - 19 May 2026

Viewed by 588

Abstract

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 [...] Read more.

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 s^z again 760 ± 40 Pa s^z and 597 ± 2 Pa s^z again 604 ± 4 Pa s^z 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 (

µ_{0}

) 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. Full article

(This article belongs to the Special Issue Rheological and Gelling Properties of Gels for Food Applications)

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19 pages, 2915 KB

Open AccessArticle

Silk Microfiber-Reinforced Biomass Aerogel with Cobweb-like Pore Structure for Highly Efficient Eco-Friendly Air Filtration

by Kao Wu, Zihan Yu, Zixuan Yang, Yingjie Ding, Hong Qian, Ying Kuang, Man Xiao, Fatang Jiang and Bo Peng

Gels 2026, 12(5), 443; https://doi.org/10.3390/gels12050443 - 19 May 2026

Viewed by 731

Abstract

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. [...] Read more.

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 PM_2.5 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. Full article

(This article belongs to the Special Issue Biopolymer-Based Gels for Food Applications)

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18 pages, 3332 KB

Open AccessArticle

Preparation, Properties and Application Research of PVA/ANF/NaCl Composite Organic Hydrogel

by Guofan Zeng, Jiaqi Zhu, Zehong Wu, Yihan Qiu and Mingcen Weng

Gels 2026, 12(5), 442; https://doi.org/10.3390/gels12050442 - 19 May 2026

Viewed by 908

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Gel-Based Scaffolds for Tissue Engineering)

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18 pages, 3490 KB

Open AccessArticle

Snail Mucus-Inspired Interface: A Resilient and Self-Healing Double-Network Hydrogel Polymer Electrolyte for Flexible Supercapacitors

by Mengxiao Wang, Jia Yang, Gang Qin and Qiang Chen

Gels 2026, 12(5), 441; https://doi.org/10.3390/gels12050441 - 17 May 2026

Viewed by 563

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Polymer Hydrogels and Networks)

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24 pages, 2814 KB

Open AccessReview

Decoupling Mechanical and Conductive Properties of Cellulose Ionogels for Flexible Electronics: A Review

by Zhixuan Yang, Shuailin Li, Youjia Yang, Jiawei Yang, Ruiying Zhang, Jianguo Li and Bin Chen

Gels 2026, 12(5), 440; https://doi.org/10.3390/gels12050440 - 17 May 2026

Cited by 1 | Viewed by 842

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Properties and Applications of Cellulose-Based Gel)

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17 pages, 10866 KB

Open AccessArticle

Carbonized Composites Containing Silica Aerogels with Enhanced Hydrophobicity and Thermal Insulation via Glass Fiber and Hollow Microsphere Reinforcement

by Yuquan Cao, Ruliang Li, Zikang Chen, Miao Liu, Yumin Duan, Shuai Li and Zhi Li

Gels 2026, 12(5), 439; https://doi.org/10.3390/gels12050439 - 17 May 2026

Cited by 1 | Viewed by 606

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Recent Advances in Functionalized Aerogels: Preparation, Modification and Applications)

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18 pages, 2285 KB

Open AccessArticle

Interactions of Oat β-Glucan, Protein, and Starch Under High Hydrostatic Pressure and Their Influence on Starch Properties

by Yangyang Chen, Ying Miao, Rui Huo, Minjun Sun, Jingyu Xie and Meili Zhang

Gels 2026, 12(5), 438; https://doi.org/10.3390/gels12050438 - 16 May 2026

Viewed by 622

Abstract

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 [...] Read more.

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. Full article

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

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25 pages, 8096 KB

Open AccessEditor’s ChoiceArticle

Hydrophilic Anhydride-Containing Oligomers for Two-Component Hydrogels: From Biopolymer Compatibility to Cytocompatible Gelatin Bioinks

by Julia C. Matros, Katharina E. Wiebe-Ben Zakour, Joana Witt and Michael C. Hacker

Gels 2026, 12(5), 437; https://doi.org/10.3390/gels12050437 - 16 May 2026

Viewed by 857

Abstract

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) [...] Read more.

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. Full article

(This article belongs to the Special Issue Gels in Tissue Engineering)

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43 pages, 2270 KB

Open AccessReview

Silk Fibroin–Polyphenol Gels and Hydrogels: Molecular Interactions, Gelation Strategies, Responsive Behaviors, and Multifunctional Applications

by Simeng Ma, Zhuanghong Wang, Honghao Fan and Hai He

Gels 2026, 12(5), 436; https://doi.org/10.3390/gels12050436 - 15 May 2026

Cited by 4 | Viewed by 972

Abstract

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 [...] Read more.

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. Full article

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

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18 pages, 7491 KB

Open AccessArticle

Synergistic Mechanisms of Surfactants and Monovalent Ions for Enhanced Oil Recovery Through Interfacial Properties and Microfluidic Study

by Xuchun Yang, Yafei Liu, Fen He, Chenlu Du, Jingdi Zheng and Desheng Zhou

Gels 2026, 12(5), 435; https://doi.org/10.3390/gels12050435 - 15 May 2026

Cited by 1 | Viewed by 436

Abstract

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 [...] Read more.

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. Full article

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

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23 pages, 9551 KB

Open AccessArticle

Iron Oxide–Chitosan Macroporous Nanocomposite Hydrogels for Efficient Heterogeneous Electro-Fenton Degradation of Ciprofloxacin

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

Gels 2026, 12(5), 434; https://doi.org/10.3390/gels12050434 - 15 May 2026

Viewed by 741

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Recent Advances in Biopolymer Gels (3rd Edition))

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29 pages, 3138 KB

Open AccessReview

Temperature/pH Dual-Responsive Hydrogels: Research Progress in Preparation Methods, Structural Design Strategies and Biomedical Applications

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

Gels 2026, 12(5), 433; https://doi.org/10.3390/gels12050433 - 15 May 2026

Cited by 3 | Viewed by 1729

Abstract

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, [...] Read more.

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. Full article

(This article belongs to the Special Issue Shaping the Future with Thermoresponsive Gels: Smart Materials for Emerging Technologies)

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13 pages, 2664 KB

Open AccessArticle

Physicochemical and Thermal Properties of Aluminosilicate Gels Based on Metakaolin Doped with Different Amounts of Samarium(III)-Oxide

by Sanja Knežević, Marija Ivanović, Snežana Nenadović, Dorota Korte, Swapna Mohanachandran Nair Sindhu, Marijan Nečemer and Miloš Nenadović

Gels 2026, 12(5), 432; https://doi.org/10.3390/gels12050432 - 15 May 2026

Viewed by 594

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Characterization Techniques for Hydrogels and Their Applications)

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14 pages, 3233 KB

Open AccessArticle

Superabsorbent Hydrogels Derived from Unpurified Sargassum Biomass via Direct Carboxymethylation and Crosslinking

by Cleny Villalva-Cañavi, Alma Berenice Jasso-Salcedo and Daniel Lardizabal-Gutierrez

Gels 2026, 12(5), 431; https://doi.org/10.3390/gels12050431 - 15 May 2026

Viewed by 898

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Advances in Functional Gel (3rd Edition))

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15 pages, 899 KB

Open AccessArticle

Controlling Freeze–Thaw Gelation of Egg Yolk via Enzymatic Treatment

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

Gels 2026, 12(5), 430; https://doi.org/10.3390/gels12050430 - 14 May 2026

Viewed by 935

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Food Gels: Structure and Function (2nd Edition))

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12 pages, 971 KB

Open AccessReview

Clinical Applications and Therapeutic Potential of Nano-Bio Fusion Gel in Oral Soft Tissue Therapy: A Critical Narrative Review

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

Gels 2026, 12(5), 429; https://doi.org/10.3390/gels12050429 - 14 May 2026

Viewed by 1397

Abstract

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 [...] Read more.

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. Full article

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

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19 pages, 3714 KB

Open AccessArticle

Magnetic P(AA-AM)/SA-BC-Fe₃O₄ Composite Hydrogel: Synthesis, Characterization, and Enhanced Adsorption Performance for Methylene Blue

by Yunxiang Zheng, Yonghan Wang, Mengmeng Wang, Chunxiao Zhang and Xiangpeng Wang

Gels 2026, 12(5), 428; https://doi.org/10.3390/gels12050428 - 13 May 2026

Viewed by 446

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Section Gel Applications)

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34 pages, 8651 KB

Open AccessReview

Recent Advances and Applications of Chitin and Chitosan Hydrogel Scaffolds in Tissue Engineering

by A. M. Abdel-Mohsen, Rasha M. Abdel-Rahman and Katerina Skotnicova

Gels 2026, 12(5), 427; https://doi.org/10.3390/gels12050427 - 13 May 2026

Cited by 3 | Viewed by 1896

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Gel-Based Scaffolds for Tissue Engineering)

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37 pages, 16775 KB

Open AccessReview

Developing a Clinically Practical Biomaterial Platform for Endogenous Liver Regeneration

by 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 and Avik Som

Gels 2026, 12(5), 426; https://doi.org/10.3390/gels12050426 - 13 May 2026

Viewed by 1783

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Advanced Soft Gels with Enhanced Functionality for Biomedical and Additive Manufacturing Applications (2nd Edition))

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22 pages, 7511 KB

Open AccessArticle

Hyaluronic Acid Improves Stability in Ovalbumin-Tea Polyphenol Pickering Particle-Stabilized Gel-like HIPEs via Interfacial Reinforcement

by Jingchun Ma, Shenghui Bi, Xue Yang, E Zhao, Ying Zhou, Chun Ye, Yuanyuan Liu and Qiujin Zhu

Gels 2026, 12(5), 425; https://doi.org/10.3390/gels12050425 - 13 May 2026

Cited by 1 | Viewed by 790

Abstract

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, [...] Read more.

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. Full article

(This article belongs to the Special Issue Development of Gels and Gelatin in Food Products)

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20 pages, 20347 KB

Open AccessArticle

Individual and Synergistic Effects of Hybrid PVA–Steel Fiber on Mechanical Properties of Nano-SiO₂ Modified Epoxy Resin Gel Mortar

by Peng Zhang, Xiao Zhang, Xiaobing Dai and Shiyao Wei

Gels 2026, 12(5), 424; https://doi.org/10.3390/gels12050424 - 12 May 2026

Cited by 2 | Viewed by 465

Abstract

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 [...] Read more.

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 R_5,10 and R_10,20 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. Full article

(This article belongs to the Special Issue Novel Polymer Gels: Synthesis, Properties, and Applications (2nd Edition))

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Gels, Volume 12, Issue 5 (May 2026) – 105 articles

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