Gels

14 pages, 2204 KiB

Open AccessArticle

Development and Application of a Modified Biochar-Calcium Alginate Composite (MB-CA) for In Situ Remediation of Cadmium-Contaminated Soil

by Sijia Sun, Yuying Wang, Yanru Zhang, Lina Wu, Xinyi Wang, Guoyu Wang, Weitao Sun, Dasong Lin and Yajun Wang

Gels 2025, 11(5), 375; https://doi.org/10.3390/gels11050375 - 20 May 2025

Abstract

Agricultural monitoring reveals cadmium (Cd) as the most prevalent heavy metal pollutant in Chinese agricultural soils, with 7.0% of sampled sites exceeding the national soil environmental quality standard (GB 15618-2018), creating substantial risks for crop safety. In situ remediation is a cost-effective method [...] Read more.

Agricultural monitoring reveals cadmium (Cd) as the most prevalent heavy metal pollutant in Chinese agricultural soils, with 7.0% of sampled sites exceeding the national soil environmental quality standard (GB 15618-2018), creating substantial risks for crop safety. In situ remediation is a cost-effective method that can modify the speciation and migration properties of Cd in soil. The previous stage of research studies conducted basic characterization of materials and predicted their adsorption capacity in solution environments. This study focuses on the application effects in soil environment. We cross-linked modified biochar and calcium alginate hydrogels to fabricate a composite material (MB-CA) and determined its excellent adsorption performance for cadmium. This study is a continuation of our previous work, focusing on determining the thermodynamic model of adsorption materials, the applicable environment of composite materials, the influence on soil microorganisms, and its effect on the reduction in Cd content in agricultural products. The research found that the adsorption of Cd²⁺ by MB-CA conforms to the Freundlich isotherm model. MB-CA has the ability to regulate pH, achieving outstanding adsorption capacity at pH 4–6. The effect of MB-CA on lettuce is verified through pot experiment and field experiment. The Cd²⁺ content in plants decreased by 63.11% and 76.92%, respectively. Additionally, MB-CA did not negatively impact microbial abundance. This study further discussed the performance and application effect of MB-CA, providing new solutions for soil remediation. Full article

(This article belongs to the Special Issue Social Implementation of Advanced Gel Materials)

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18 pages, 1648 KiB

Open AccessArticle

Exploring the Potential of Cleansing Hydrogel and Shampoo with Whey as a Contemporary Approach to Sustainability

by Maja Bjelošević Žiberna, Blaž Grilc, Mirjana Gašperlin and Mirjam Gosenca Matjaž

Gels 2025, 11(5), 374; https://doi.org/10.3390/gels11050374 - 20 May 2025

Abstract

Cosmetology is one of the fastest-growing scientific areas, and within it, individual needs and preferences have to be considered. Specifically, cosmetic products with incorporated biological macromolecules, i.e., proteins and peptides, that contribute to improved skin features are gaining in importance. Similar to other [...] Read more.

Cosmetology is one of the fastest-growing scientific areas, and within it, individual needs and preferences have to be considered. Specifically, cosmetic products with incorporated biological macromolecules, i.e., proteins and peptides, that contribute to improved skin features are gaining in importance. Similar to other fields, cosmetology is also faced with the zero-waste paradigm and strives for a collaboration with other industries. Whey is a co-product in milk production and represents a high environmental burden. In this regard, the idea of the present study was to utilise whey in order to develop sustainable cosmetic products, i.e., cleansing hydrogel and shampoo. The initial phase of the study was dedicated to the development of an optimised hydrogel and shampoo base, followed by whey integration and an in-depth physico-chemical characterisation of both prototypes. In the subsequent phases, particular emphasis was placed on evaluating the potential skin irritancy of the whey-based formulations in vitro, complemented by in vivo assessment on volunteers. The results obtained indicate that the incorporation of whey at concentrations of up to 30% (m/m) is feasible for both formulation types. Moreover, neither product exhibited any irritative effects and a study on volunteers showed that whey has great potential in terms of providing adequate skin hydration. Taken together, all the findings support the development of advanced cosmetic formulations with a zero-waste concept built-in, thus offering a promising platform for cross-sector collaboration, and representing a meaningful step toward potential hydrogel and shampoo commercialisation. Full article

(This article belongs to the Special Issue Global Excellence in Bioactive Gels)

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26 pages, 19631 KiB

Open AccessArticle

Design of a Foam-Actuated Nano-Emulgel for Perioceutic Drug Delivery: Formulation, Characterization, and Antimicrobial Efficacy

by Theresa P. K. Varughese, Poornima Ramburrun, Nnamdi I. Okafor, Sandy van Vuuren and Yahya E. Choonara

Gels 2025, 11(5), 373; https://doi.org/10.3390/gels11050373 - 20 May 2025

Abstract

Periodontitis is a prevalent oral condition worldwide. Azithromycin, a conventional lipophilic drug for periodontal treatment, often causes systemic side effects when administered orally. To address this, azithromycin-loaded nano-emulgels were developed using olive oil as a carrier within a xanthan gum aqueous gel phase. [...] Read more.

Periodontitis is a prevalent oral condition worldwide. Azithromycin, a conventional lipophilic drug for periodontal treatment, often causes systemic side effects when administered orally. To address this, azithromycin-loaded nano-emulgels were developed using olive oil as a carrier within a xanthan gum aqueous gel phase. This oil-in-aqueous gel emulsion was actuated into a foam for localized drug delivery in gingival and periodontal disease. The solubility of azithromycin in various vehicles was tested, with olive oil showing the best solubility (0.347 mg/mL). Thermodynamic stability testing identified viable nano-formulations, with encapsulation efficiencies ranging from 98 to 100%. These formulations exhibited rapid drug release within 2–8 h. Muco-adhesion studies and ex vivo permeability tests on porcine buccal mucosa highlighted the beneficial properties of xanthan gum for local drug retention within the oral cavity. Antimicrobial efficiency was assessed using minimum inhibitory concentrations against various oral pathogens, where the formulation with equal surfactant and co-surfactant ratios showed the most potent antibacterial activity, ranging from 0.390 to 1.56 µg/mL. This was supported by the shear-thinning, muco-adhesive, and drug-retentive properties of the xanthan gel base. The study also examined the influence of the oil phase with xanthan gum gel on foam texture, rheology, and stability, demonstrating a promising prototype for periodontitis treatment. Full article

(This article belongs to the Special Issue Hydrogels, Oleogels and Bigels Used for Drug Delivery)

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33 pages, 9324 KiB

Open AccessReview

Hydrogels for Translucent Wearable Electronics: Innovations in Materials, Integration, and Applications

by Thirukumaran Periyasamy, Shakila Parveen Asrafali and Jaewoong Lee

Gels 2025, 11(5), 372; https://doi.org/10.3390/gels11050372 - 20 May 2025

Abstract

Recent advancements in wearable electronics have significantly enhanced human–device interaction, enabling applications such as continuous health monitoring, advanced diagnostics, and augmented reality. While progress in material science has improved the flexibility, softness, and elasticity of these devices for better skin conformity, their optical [...] Read more.

Recent advancements in wearable electronics have significantly enhanced human–device interaction, enabling applications such as continuous health monitoring, advanced diagnostics, and augmented reality. While progress in material science has improved the flexibility, softness, and elasticity of these devices for better skin conformity, their optical properties, particularly transparency, remain relatively unexplored. Transparent wearable electronics offer distinct advantages: they allow for non-invasive health monitoring by enabling a clear view of biological systems and improve aesthetics by minimizing the visual presence of electronics on the skin, thereby increasing user acceptance. Hydrogels have emerged as a key material for transparent wearable electronics due to their high water content, excellent biocompatibility, and tunable mechanical and optical properties. Their inherent softness and stretchability allow intimate, stable contact with dynamic biological surfaces. Furthermore, their ability to support ion-based conductivity is advantageous for bioelectronic interfaces and physiological sensors. Current research is focused on advancing hydrogel design to improve transparency, mechanical resilience, conductivity, and adhesion. The core components of transparent wearable systems include physiological sensors, energy storage devices, actuators, and real-time displays. These must collectively balance efficiency, functionality, and long-term durability. Practical applications span continuous health tracking and medical imaging to next-generation interactive displays. Despite progress, challenges such as material durability, scalable manufacturing, and prolonged usability remain. Addressing these limitations will be crucial for the future development of transparent, functional, and user-friendly wearable electronics. Full article

(This article belongs to the Special Issue Gel-Based Materials for Intelligent Sensors and Self-Powered Nanogenerators)

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14 pages, 671 KiB

Open AccessReview

White Spot Lesion Treatment Options: A Systematic Review of Different Techniques for Masking These Lesions

by Michela Lamorgese, Nélio Veiga, Maria J. Correia, Ana T. P. C. Gomes, Sara Lopes, Lígia Lopes-Rocha, Rita Fidalgo-Pereira and Pedro C. Lopes

Gels 2025, 11(5), 371; https://doi.org/10.3390/gels11050371 - 19 May 2025

Abstract

White spot lesions (WSLs) are early clinical stages of enamel demineralization, often related to orthodontic treatment or poor oral hygiene. The use of gels such as fluoride for topical application inhibits demineralization and promotes remineralization of dental tissues through various mechanisms. A variety [...] Read more.

White spot lesions (WSLs) are early clinical stages of enamel demineralization, often related to orthodontic treatment or poor oral hygiene. The use of gels such as fluoride for topical application inhibits demineralization and promotes remineralization of dental tissues through various mechanisms. A variety of therapeutic approaches are available; however, recent research indicates that combined treatment strategies may yield superior clinical outcomes compared to monotherapy. The aim of this study was to critically compare the efficacy of combining multiple treatment techniques for WSLs compared to using these techniques alone. A systematic search was conducted in PubMed, Scopus, and Cochrane databases according to PRISMA guidelines. The PICO strategy was used to formulate the research question: Which clinical approaches combined or isolated (C) influence the treatment and prevention effectiveness (O) of white spot lesions (I) in humans (P) in the last ten years (T)? Inclusion criteria focused on clinical studies from the last ten years evaluating the combined use of at least two treatment techniques for WSL, resulting in a total of 8 randomized controlled trials selected from an initial pool of 1185 articles. Our results suggest that combined treatment strategies, including resin infiltration with fluoride varnish and ozone therapy combined with fluoride application, demonstrated enhanced efficacy in lesion masking and remineralization compared to single-treatment approaches. CPP-ACP and hydroxyapatite-based creams improved aesthetics, particularly when used alongside fluoride varnish. Our study concluded that the combination of remineralization agents like fluoride gel, infiltrative resins, and antimicrobial treatments offers superior outcomes on white spot lesion treatment than using these techniques alone. However, long-term clinical studies are needed to standardize treatment protocols and confirm durability. Full article

(This article belongs to the Special Issue Functional Gels for Dental Applications)

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23 pages, 5188 KiB

Open AccessArticle

Dynamic Boronate Ester Based Hydrogel with Enhanced Mechanical Properties and Multi-Stimuli-Triggered Release for Tissue Repair and Antioxidant Therapy

by Fangyi Liu, Gaoyang Li, Zhenhui An, Sijia Wang, Shouhong Xu and Honglai Liu

Gels 2025, 11(5), 370; https://doi.org/10.3390/gels11050370 - 18 May 2025

Abstract

Oxidative stress and chronic inflammation play pivotal roles in causing impaired tissue regeneration and delaying wound healing processes. Epigallocatechin gallate (EGCG) demonstrates robust anti-inflammatory and antioxidant characteristics, thereby emerging as a highly promising therapeutic substance for tissue repair applications. In order to counteract [...] Read more.

Oxidative stress and chronic inflammation play pivotal roles in causing impaired tissue regeneration and delaying wound healing processes. Epigallocatechin gallate (EGCG) demonstrates robust anti-inflammatory and antioxidant characteristics, thereby emerging as a highly promising therapeutic substance for tissue repair applications. In order to counteract the pathological characteristics of the wound microenvironment, including increased levels of reactive oxygen species (ROS), low pH (weak acidic conditions), and elevated glucose concentrations, a hydrogel with pH/ROS/glucose-responsive properties was fabricated. This hydrogel was modified with phenylboronic acid (PBA) groups, which not only enhance its mechanical strength but also endow it with multi-stimuli responsiveness via dynamic boronate ester bonds. The impacts of grafting of PBA and loading of EGCG on the rheological and mechanical properties, as well as the network structure of the hydrogels, were systematically investigated. Moreover, in vitro experiments showed that the hydrogel could achieve excellent sustained and controlled release of both small-molecule and macromolecular drugs. Additionally, cell viability tests verified the hydrogel’s outstanding biocompatibility, and antioxidant experiments demonstrated its efficient ability to scavenge intracellular ROS. In conclusion, this injectable and biodegradable hydrogel possesses multi-stimuli responsiveness, controllable drug release behavior, and antioxidant capacity, presenting a promising approach to alleviate oxidative damage and promote tissue repair. This study offers valuable perspectives for the design of advanced hydrogel materials aimed at treating wound healing. Full article

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15 pages, 2205 KiB

Open AccessArticle

Highly Stretchable, Low Hysteresis, and Transparent Ionogels as Conductors for Dielectric Elastomer Actuators

by Limei Zhang, Hong Li, Zhiquan Li, Weimin Pan, Yi Men, Niankun Zhang, Jing Xu and Xuewei Liu

Gels 2025, 11(5), 369; https://doi.org/10.3390/gels11050369 - 17 May 2025

Abstract

As conductive materials, ionogels have attracted significant attention for their potential applications in flexible wearable electronics. However, preparing an ionogel with mechanical properties akin to human skin while also achieving transparency, adhesion, and low hysteresis through simple processes remains challenging. Here, we introduce [...] Read more.

As conductive materials, ionogels have attracted significant attention for their potential applications in flexible wearable electronics. However, preparing an ionogel with mechanical properties akin to human skin while also achieving transparency, adhesion, and low hysteresis through simple processes remains challenging. Here, we introduce a multifunctional ionogel synthesized via a one-step photopolymerization method. By leveraging the good compatibility between the ionic liquid and the polymer network, as well as the hydrogen bonding and chemical crosslinking within the gel network, we achieved an ionogel with high transparency (>98%), stretchability (fracture strain of 19), low hysteresis (<5.83%), strong adhesion, robust mechanical stability, excellent electrical properties, a wide operating temperature range, and a tunable modulus (1–103 kPa) that matches human skin. When used as a conductor in soft actuators, the ionogel enabled a large area strain of 36% and a fast electromechanical conversion time of less than 1 s. The actuator demonstrated good actuation performance with voltage and frequency dependence, electrochemical stability, and outstanding durability over millions of cycles. This study provides a simple and effective method to produce multifunctional ionogels with tailored mechanical properties that match those of human skin, paving the way for their application in flexible wearable electronics. Full article

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

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16 pages, 9987 KiB

Open AccessArticle

Preparation of Janus-Structured Evaporators for Enhanced Solar-Driven Interfacial Evaporation and Seawater Desalination

by Junjie Liao, Luyang Hu, Haoran Wang, Zhe Yang, Xiaonan Wu and Yumin Zhang

Gels 2025, 11(5), 368; https://doi.org/10.3390/gels11050368 - 17 May 2025

Abstract

Solar-driven interfacial evaporation has emerged as a sustainable and highly efficient technology for seawater desalination, attracting considerable attention for its potential to address global water scarcity. However, challenges such as low evaporation rates and salt accumulation significantly hinder the performance and operational lifespan [...] Read more.

Solar-driven interfacial evaporation has emerged as a sustainable and highly efficient technology for seawater desalination, attracting considerable attention for its potential to address global water scarcity. However, challenges such as low evaporation rates and salt accumulation significantly hinder the performance and operational lifespan of evaporators. Here, we present an innovative Janus-structured evaporator featuring distinct operational mechanisms through the integration of a hydrophobic PVDF-HFP@PPy photothermal membrane and a hydrophilic PVA-CF@TA-Fe³⁺ hydrogel, coupled with a unidirectional flow configuration. Distinct from conventional Janus evaporators that depend on interfacial water transport through asymmetric layers, our design achieves two pivotal innovations: (1) the integration of a lateral fluid flow path with the Janus architecture to enable sustained brine replenishment and salt rejection and (2) the creation of dual vapor escape pathways (hydrophobic and hydrophilic layers) synergized with hydrogel-mediated water activation to elevate evaporation kinetics. Under 1 sun illumination, the evaporator achieves a maximum evaporation rate of 2.26 kg m⁻² h⁻¹ with a photothermal efficiency of 84.6%, in both unidirectional flow and suspension modes. Notably, the evaporation performance remains stable across a range of saline conditions, demonstrating remarkable resistance to salt accumulation. Even during continuous evaporation of highly saline water (10% brine), the evaporator maintains an evaporation rate of 2.10 kg m⁻² h⁻¹ without observable salt precipitation. The dual anti-salt strategies—enabled by the Janus structure and unidirectional flow design—underscore the evaporator’s capability for sustained high performance and long-term stability in saline environments. These findings provide valuable insights into the development of next-generation solar evaporators that deliver high performance, long-term stability, and robustness in saline and hypersaline environments. Full article

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

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20 pages, 4445 KiB

Open AccessArticle

Investigating the Interactions of Peptide Nucleic Acids with Multicomponent Peptide Hydrogels for the Advancement of Healthcare Technologies

by Sabrina Giordano, Monica Terracciano, Enrico Gallo, Carlo Diaferia, Andrea Patrizia Falanga, Antonella Accardo, Monica Franzese, Marco Salvatore, Gennaro Piccialli, Nicola Borbone and Giorgia Oliviero

Gels 2025, 11(5), 367; https://doi.org/10.3390/gels11050367 - 17 May 2025

Abstract

This study reports the development of peptide-based hydrogels for the encapsulation and controlled release of peptide nucleic acids in drug delivery applications. Ultrashort aromatic peptides, such as Fmoc-FF, self-assemble into biocompatible hydrogels with nanostructured architectures. The functionalization of tripeptides (Fmoc-FFK and Fmoc-FFC) with [...] Read more.

This study reports the development of peptide-based hydrogels for the encapsulation and controlled release of peptide nucleic acids in drug delivery applications. Ultrashort aromatic peptides, such as Fmoc-FF, self-assemble into biocompatible hydrogels with nanostructured architectures. The functionalization of tripeptides (Fmoc-FFK and Fmoc-FFC) with lysine (K) or cysteine (C) enables electrostatic or covalent interactions with model PNAs engineered with glutamic acid or cysteine residues, respectively. Hydrogels were polymerized in situ in the presence of PNAs, and component ratios were systematically varied to optimize mechanical properties, loading efficiency, and release kinetics. The formulations obtained with a 1/10 ratio of Fmoc-FF(K or C)/Fmoc-FF provided an optimal balance between structural integrity and delivery performance. All hydrogel formulations demonstrated high stiffness (G′ > 19,000 Pa), excellent water retention, and minimal swelling under physiological conditions (ΔW < 4%). The release studies over 10 days showed that electrostatic loading enabled faster and higher release (up to 90%), while covalent bonding resulted in slower, sustained delivery (~15%). These findings highlight the tunability of the hydrogel system for diverse therapeutic applications. Full article

(This article belongs to the Special Issue Hydrogels with Appropriate/Tunable Properties for Biomedical Applications (3rd Edition))

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20 pages, 6700 KiB

Open AccessArticle

The Hypoglycemic Activity of Gracilaria lemaneiformis Polysaccharide Gels Based on IR/IRS-2/PI3k/Akt/Glut4 and Glycometabolism Signaling Pathways in HepG2 Cells

by Xiaoshan Long, Shucheng Liu, Xianqing Yang, Yongqiang Zhao, Shaoling Yang, Ya Wei, Chuang Pan, Shengjun Chen, Peihong Jiang, Bo Qi and Xiao Hu

Gels 2025, 11(5), 366; https://doi.org/10.3390/gels11050366 - 15 May 2025

Abstract

The aim of this study was to investigate the hypoglycemic activity and mechanism of G. lemaneiformis polysaccharide gels (GLP and GLP-HV) based on IR/IRS-2/PI3k/Akt/Glut4 and glycometabolism signaling pathways in HepG2 cells. After H₂O₂-Vc degradation, the molecular weight of G. [...] Read more.

The aim of this study was to investigate the hypoglycemic activity and mechanism of G. lemaneiformis polysaccharide gels (GLP and GLP-HV) based on IR/IRS-2/PI3k/Akt/Glut4 and glycometabolism signaling pathways in HepG2 cells. After H₂O₂-Vc degradation, the molecular weight of G. lemaneiformis polysaccharide gel declined from 1478 kDa to 16 kDa. Molecular weight chromatogram and distribution indicated that GLP-HV had a high molecular weight homogeneity compared to GLP. G. lemaneiformis polysaccharide gels significantly decreased the TC, TG, LDL-C, MDA, and LDH contents and enhanced the activities of HDL-C, T-AOC, CAT, GSH-PX, SOD, insulin, and glycogen in HepG2 cells. Fluorescent staining results showed that G. lemaneiformis polysaccharide gels reduced ROS and calcium ions levels in HepG2 cells. GLP and GLP-HV displayed excellent hypoglycemic activity, with GLP-HV performing better. Furthermore, qPCR and Western blot analysis revealed that G. lemaneiformis polysaccharide gels remarkably strengthened the levels of IR, IRS-2, PI3K, Akt, Glut4, HK, G6PD, PFK, PEPCK, GK, PK genes, and proteins. Spearman’s correlation analysis revealed that the IR/IRS-2/PI3k/Akt/Glut4 signaling pathway played a dominant role in regulating activity. These results show that G. lemaneiformis polysaccharide gels present a prominent hypoglycemic effect mediated by the IR/IRS-2/PI3k/Akt/Glut4 and glycometabolism signaling pathways, with the former playing a dominant role. Full article

(This article belongs to the Special Issue Food Gels: Gelling Process and New Applications)

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22 pages, 5233 KiB

Open AccessArticle

A Novel Green In Situ Amine-Functionalized Aerogel UiO-66-NH₂/TOCNF for the Removal of Azo Anionic Dyes

by Rabia Amen, Islam Elsayed, Yunsang Kim, Gregory T. Schueneman, Emad M. El-Giar and El Barbary Hassan

Gels 2025, 11(5), 365; https://doi.org/10.3390/gels11050365 - 15 May 2025

Abstract

UiO-66-NH₂ is a metal–organic framework (MOF) with open metal sites, making it a promising candidate for adsorption and catalysis. However, the powdery texture of MOFs and the use of toxic solvents during synthesis limit their application. A novel solution to this issue [...] Read more.

UiO-66-NH₂ is a metal–organic framework (MOF) with open metal sites, making it a promising candidate for adsorption and catalysis. However, the powdery texture of MOFs and the use of toxic solvents during synthesis limit their application. A novel solution to this issue is to create a layered porous composite by encasing the MOF within a flexible and structurally robust aerogel substrate using safe, eco-friendly, and green solvents such as ethanol. The fibrous MOF aerogels, characterized by a desirable macroscopic shape of cylindrical block and hierarchical porosity, were synthesized by two approaches: in situ growth of amine-functionalized UiO-66-NH₂ crystals on a TEMPO-oxidized cellulose nanofiber (TOCNF) and ex situ crosslinking of UiO-66-NH₂ crystals onto a TOCNF network to form UiO-66-NH₂/TOCNF. The incorporation of MOF into the cellulose nanofibrils via the in situ method reduces their aggregation potential, alters the nucleation/growth balance to produce smaller MOF crystals, and enhances mechanical flexibility, as evidenced by SEM images. The three adsorbents, including UiO-66-NH₂, ex situ UiO-66-NH₂/TOCNF, and in situ UiO-66-NH₂/TOCNF, were synthesized and used in this study. The effects of pH, time, temperature, and initial concentration were studied. A maximum adsorption capacity (Qmax) of 549.45 mg/g for Congo Red (CR) and 171.23 mg/g for Orange II (ORII) was observed at pH 6, using 10 mg of in situ UiO-66-NH₂/TOCNF at 40 °C with a contact time of 75 min for CR and 2 h for ORII. The adsorption of both dyes primarily occurs through monolayer chemisorption on the in situ UiO-66-NH₂/TOCNF. The main removal mechanisms were hydrogen bonding and surface complexation. The noteworthy adsorption capacity of in situ UiO-66-NH₂/TOCNF coupled with environment-friendly fabrication techniques indicates its potential applications on a large scale in real wastewater systems. Full article

(This article belongs to the Special Issue Cellulose-Based Gels: Synthesis, Properties, and Applications)

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25 pages, 3964 KiB

Open AccessArticle

Development of Liposome-Based Hydrogel Patches Incorporating Essential Oils of African Plants and Deep Eutectic Solvents

by Wanhang Jiang, Sara Toufouki, Subhan Mahmood, Ali Ahmad, Alula Yohannes, Yang Xiang and Shun Yao

Gels 2025, 11(5), 364; https://doi.org/10.3390/gels11050364 - 15 May 2025

Abstract

A nanoliposome-integrated polymeric hydrogel was developed for the controlled release of essential oils (Argania spinosa, Passiflora edulis). A deep eutectic solvent (DES) composed of betaine and phytic acid enhanced the solubility and stability of essential oils, facilitating uniform encapsulation within nanoliposomes. The hydrogel [...] Read more.

A nanoliposome-integrated polymeric hydrogel was developed for the controlled release of essential oils (Argania spinosa, Passiflora edulis). A deep eutectic solvent (DES) composed of betaine and phytic acid enhanced the solubility and stability of essential oils, facilitating uniform encapsulation within nanoliposomes. The hydrogel exhibited a swelling capacity of 100% and retained 51.7% of water after 7 h, ensuring prolonged hydration. Structural analysis confirmed a homogeneous dispersion of nanoliposomes, contributing to the gradual release of bioactive components. Additionally, the hydrogel demonstrated high mechanical strength (7.5 MPa), ensuring flexibility and durability. The polymeric network, formed by acrylamide, sodium alginate, and bentonite, provided a stable and elastic matrix, optimizing water retention and mechanical performance. The controlled diffusion mechanism of the nanoliposomes was validated through in vitro release studies, indicating Fickian-controlled release behavior. These findings highlight the potential of this polymeric hydrogel system as a functional material for skincare formulations, offering enhanced hydration and sustained bioactive delivery. Full article

(This article belongs to the Special Issue Oleogels, Bigels, and Emulgels: Fabrication, Application and Research Trends)

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22 pages, 15068 KiB

Open AccessArticle

Utilization of Cassava Starch–Glycerol Gel as a Sustainable Material to Decrease Metal Ion Surface Contamination

by Rezky Anggakusuma, Gemilang Lara Utama, Dadan Sumiarsa, Permata Apriliani Dewi Muslimah and Ali Asgar

Gels 2025, 11(5), 363; https://doi.org/10.3390/gels11050363 - 14 May 2025

Abstract

Many studies have examined the ability of polymer-based gels or hydrogels to serve various purposes, particularly as absorbents. Several studies have reported that polyvinyl alcohol (PVA), with specific compositions and additives, is an absorbent and a decontamination material usable for heavy metals and [...] Read more.

Many studies have examined the ability of polymer-based gels or hydrogels to serve various purposes, particularly as absorbents. Several studies have reported that polyvinyl alcohol (PVA), with specific compositions and additives, is an absorbent and a decontamination material usable for heavy metals and radioactive substances. PVA has a high cost and is slowly degradable under anaerobic conditions. This study investigated the potential of natural materials, namely cassava starch, which is an environmentally friendly, non-toxic, and readily available gel-forming polymer that, notably, is inexpensive in Indonesia. The FTIR analysis showed a bond and polymer formation between cassava starch and glycerol. The cassava starch–glycerol–water mixture was applied to media such as glass, aluminum plates, and ceramics contaminated with heavy-metal stable ions which correspond to a radionuclide. The media, stored at room temperature for 24 h, becomes a film. According to the SEM and XRF results, the gel becomes a film that binds and absorbs metals when dried. The SEM results showed the presence of metals corresponding with the sources of contamination, and the XRF results showed that the quantity of metals absorbed was large. The cassava starch gel absorption results indicated the formation of an amorphous compound, as indicated by the XRF results. Based on all the analyses, the cassava starch–glycerol gel has enormous potential. It is almost equivalent to a PVA gel as an absorbent material and heavy-metal decontamination material, when used for radioactive decontamination on the material’s surface. Full article

(This article belongs to the Special Issue Gel-Related Papers from the 9th Asian Conference on Colloid and Interface Science 2023 (ACCIS 2023))

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33 pages, 10150 KiB

Open AccessReview

Mechanical Properties of Cement-Based Gel Composites Reinforced by Plant Fiber: A Review

by Peng Zhang, Xiao Zhang, Jinjun Guo, Yuanxun Zheng and Zhen Gao

Gels 2025, 11(5), 362; https://doi.org/10.3390/gels11050362 - 14 May 2025

Abstract

Plant fibers (PFs) have been increasingly employed in cement-based gel composites (CCs) on account of their excellent mechanical properties, toughness and sustainability. Researchers have engaged in a lot of studies on plant fiber-reinforced cement-based gel composites (PFRCCs). Based on these studies, the chemical [...] Read more.

Plant fibers (PFs) have been increasingly employed in cement-based gel composites (CCs) on account of their excellent mechanical properties, toughness and sustainability. Researchers have engaged in a lot of studies on plant fiber-reinforced cement-based gel composites (PFRCCs). Based on these studies, the chemical components and mechanical characteristics of PFs are summed up in this review. In addition, the modification methods for matrices and PFs are also discussed. The mechanical properties of PFRCCs, including static and dynamic properties, are reviewed. Predictive equations for the mechanical properties of PFRCCs are summarized in this paper. In the end, the characteristics of the interface transition zones between PFs and CCs are analyzed. According to the results of previous studies, the addition of PFs can enhance the flexural strength and tensile strength of CCs, but it can have an uncertain effect on compressive strength. The elastic modulus and fracture behavior of PFRCCs increases with the addition of PFs. At the same time, modification methods have been proved to be useful in reducing the degradation of PFs in CCs. Generally speaking, PFRCCs are new building materials which have extensive application prospects. The aim of this review is to help researchers understand the mechanical properties of PFRCCs and to promote the application of PFRCCs in future projects. Full article

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

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24 pages, 6987 KiB

Open AccessReview

Advances in Carbon-Based Aerogels for CO₂ Capture: Fundamental Design Strategies and Technological Progress

by Shakila Parveen Asrafali, Thirukumaran Periyasamy and Gazi A. K. M. Rafiqul Bari

Gels 2025, 11(5), 361; https://doi.org/10.3390/gels11050361 - 14 May 2025

Abstract

Carbon-based aerogels have garnered significant attention for CO₂ capture owing to their low-cost precursors, tunable structures, and high porosity. Their performance in CO₂ adsorption is intricately linked to their microstructural and textural features, including pore size distribution, surface area, and surface [...] Read more.

Carbon-based aerogels have garnered significant attention for CO₂ capture owing to their low-cost precursors, tunable structures, and high porosity. Their performance in CO₂ adsorption is intricately linked to their microstructural and textural features, including pore size distribution, surface area, and surface chemistry. Micropores (<2 nm) are particularly effective due to their size compatibility with CO₂ molecules, while surface functional groups enhance adsorption through hydrogen bonding and electrostatic interactions. Strategic design approaches have focused on tailoring these properties to optimize CO₂ uptake under realistic conditions. This review provides a comprehensive overview of recent advancements in the structural engineering of carbon aerogels, emphasizing the role of hierarchical porosity and heteroatom doping (nitrogen, oxygen, sulfur, etc.) in enhancing adsorption capacity and selectivity. Experimental and theoretical studies have highlighted how the synergistic control of microstructure and surface chemistry leads to superior adsorption performance. Furthermore, this review identifies current challenges, such as limited structural stability and insufficient mechanistic understanding, which hinder further progress. Future research directions are proposed, including advanced pore architecture control, functional group engineering, and the integration of in situ characterization techniques. Overall, this review serves as a guide for the rational design of next-generation carbon-based aerogels tailored for efficient and scalable CO₂ capture technologies. Full article

(This article belongs to the Special Issue Aerogels: Recent Progress in Novel Applications)

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1 pages, 219 KiB

Open AccessCorrection

Correction: Ramírez-Chavarría et al. Study of Polyvinyl Alcohol Hydrogels Applying Physical-Mechanical Methods and Dynamic Models of Photoacoustic Signals. Gels 2023, 9, 727

by Roberto G. Ramírez-Chavarría, Argelia Pérez-Pacheco, Emiliano Terán and Rosa M. Quispe-Siccha

Gels 2025, 11(5), 360; https://doi.org/10.3390/gels11050360 - 14 May 2025

Abstract

In the original publication [...] Full article

19 pages, 1355 KiB

Open AccessReview

Recent Advances in the Utilization of Cellulose from Food Processing Byproducts for the Generation of Aerogels

by Jaspreet Kaur and Ali Ubeyitogullari

Gels 2025, 11(5), 359; https://doi.org/10.3390/gels11050359 - 14 May 2025

Abstract

Aerogels have garnered significant attention from the scientific community due to their extraordinary properties, including low density, high porosity, low thermal conductivity, and large surface area. These properties make them interesting candidates for diverse applications such as thermal insulation, drug delivery, catalysis, fillers, [...] Read more.

Aerogels have garnered significant attention from the scientific community due to their extraordinary properties, including low density, high porosity, low thermal conductivity, and large surface area. These properties make them interesting candidates for diverse applications such as thermal insulation, drug delivery, catalysis, fillers, tissue engineering, and biosensors. However, the production of conventional aerogels is often constrained by environmental issues, the high cost of raw materials, and energy-intensive fabrication methods. In contrast, cellulose aerogels have emerged as promising sustainable materials with the potential to transform various low-cost waste products into high-value biomaterials. Food-processing byproducts provide numerous untapped opportunities for the generation of aerogels. This review highlights the recent advancements in the development of cellulose aerogels derived from food processing byproducts, emphasizing their role in contributing to the circular bioeconomy. Specifically, this study focuses on the fabrication processes of cellulose aerogels from food processing byproducts, which would otherwise go to waste. The review discusses the extraction, gel formation, drying, and functionalization processes for cellulose aerogel formation, along with the environmental and economic benefits of utilizing these waste streams. Full article

(This article belongs to the Special Issue Aerogels: Promising Materials for Environmental Applications)

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26 pages, 2841 KiB

Open AccessReview

Modified Phospholipid Vesicular Gel for Transdermal Drug Delivery: The Influence of Glycerin and/or Ethanol on Their Lipid Bilayer Fluidity and Penetration Characteristics

by Marwa H. Abdallah, Mona M. Shahien, Hemat El-Sayed El-Horany and Enas Haridy Ahmed

Gels 2025, 11(5), 358; https://doi.org/10.3390/gels11050358 - 13 May 2025

Abstract

This review explores the enhanced transdermal therapy of several skin disorders with the application of carriers comprising phospholipid vesicular gel systems. Topical drug delivery has several advantages compared to other administration methods, including enhanced patient compliance, the avoidance of the first-pass impact associated [...] Read more.

This review explores the enhanced transdermal therapy of several skin disorders with the application of carriers comprising phospholipid vesicular gel systems. Topical drug delivery has several advantages compared to other administration methods, including enhanced patient compliance, the avoidance of the first-pass impact associated with oral administration, and the elimination of the need for repeated doses. Nonetheless, the skin barrier obstructs the penetration of drugs, hence affecting its therapeutic efficacy. Carriers with phospholipid soft vesicles comprise a novel strategy used to augment drug delivery into the skin and boost therapeutic efficacy. These vesicles encompass chemicals that possess the ability to fluidize phospholipid bilayers, producing a pliable vesicle that facilitates penetration into the deeper layers of the skin. Phospholipid-based vesicular carriers have been extensively studied for improved drug delivery through dermal and transdermal pathways. Traditional liposomes are limited to the stratum corneum of the skin and do not penetrate the deeper layers. Ethosomes, glycerosomes, and glycethosomes are nanovesicular systems composed of ethanol, glycerol, or a combination of ethanol and glycerol, respectively. Their composition produce pliable vesicles by fluidizing the phospholipid bilayers, facilitating deeper penetration into the skin. This article examines the impact of ethanol and glycerol on phospholipid vesicles, and outlines their respective manufacturing techniques. Thus far, these discrepancies have not been analyzed comparatively. The review details several active compounds integrated into these nanovesicular gel systems and examined through in vitro, in vivo, or clinical human trials involving compositions with various active molecules for the treatment of various dermatological conditions. Full article

(This article belongs to the Special Issue Recent Advances in Gels Engineering for Drug Delivery (2nd Edition))

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24 pages, 5625 KiB

Open AccessReview

A Review of High-Temperature Resistant Silica Aerogels: Structural Evolution and Thermal Stability Optimization

by Zhenyu Zhu, Wanlin Zhang, Hongyan Huang, Wenjing Li, Hao Ling and Hao Zhang

Gels 2025, 11(5), 357; https://doi.org/10.3390/gels11050357 - 13 May 2025

Abstract

Silica aerogels exhibit exceptionally low thermal conductivity and a low apparent density, as they are unique porous nanomaterials. They are extensively used in thermal insulation in terms of aerospace and building construction, adsorption processes for environmental applications, concentrating solar power systems, and so [...] Read more.

Silica aerogels exhibit exceptionally low thermal conductivity and a low apparent density, as they are unique porous nanomaterials. They are extensively used in thermal insulation in terms of aerospace and building construction, adsorption processes for environmental applications, concentrating solar power systems, and so on. However, the degradation of the silica aerogel’s nanoporous structure at high temperatures seriously restricts their practical applications. Through a comprehensive review of the high-temperature structural evolution and sintering mechanisms of silica aerogels, this paper introduces two strategies to enhance their thermal stability, including heteroatom doping and surface heterogeneous structure construction. In particular, atomic layer deposition (ALD) of ultra-thin coatings on silica aerogel holds significant potential for enhancing thermal stability, while preserving its ultra-low thermal conductivity. Full article

(This article belongs to the Special Issue Advanced Aerogels: From Design to Application)

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