Search Results (113)

This study presents the development and evaluation of a hydrogel-based superabsorbent polymer sensor (HSPS) for measuring soil suction and establishing the soil–water characteristic curve (SWCC) of unsaturated soils. Polyacrylamide (PAM) hydrogels were synthesized via UV-induced free radical polymerization using acrylamide with varying crosslinking degrees. The polymers were characterized through FT-IR and TGA analyses, confirming successful synthesis and high thermal stability. Swelling, water retention, and kinetic behavior were systematically investigated. Results indicated that lower crosslinking density significantly enhanced swelling capacity, reaching up to 3000% in distilled water, while saline environments reduced absorption due to ionic screening effects. Swelling kinetics followed anomalous (non-Fickian) diffusion behavior and were well described by the pseudo-second-order Schott model. The synthesized polymers were integrated into a modified high-sensitivity pressure sensor operating on the osmotic principle to measure matric suction. The system was validated using natural soil. Among the tested formulations, the HSPS-3 demonstrated the most reliable suction measurements, reaching values up to approximately 1 MPa without significant temperature sensitivity. The resulting SWCC exhibited bimodal characteristics consistent with the soil’s dual pore structure. The proposed method provides a cost-effective, simple, and efficient alternative for suction measurement, expanding the practical range of SWCC determination in unsaturated soil mechanics. Full article

Water scarcity restricts agricultural productivity and crop yield in many regions. Hydrogels have emerged as promising materials for soil amendment and soilless cultivation. Herein, cellulose hydrogels prepared from waste paper via a DMAc/LiCl solvent system (HG-WP) and from cotton microcrystalline cellulose via NaOH/aq. dissolution (HG-MCC) were investigated. HG-WP formed semi-solid, mechanically stable materials with high porosity, capable of retaining their shape during handling and plant cultivation, whereas HG-MCC appeared denser and less elastic. Their properties and agricultural performance were compared with those of a commercial polyacrylate hydrogel (HG-PA). The three hydrogels differed substantially in water capacity: HG-PA demonstrated the highest (50.13 g/g), whereas HG-WP and HG-MCC showed 30.57 and 3.66 g/g, respectively. Soil amended with 20 wt.% cellulose hydrogel exhibited improved water retention compared with untreated soil during the first 7 days of drying. Under laboratory conditions, hydrogels increased mustard biomass in soil under regular watering and plant survival under drought conditions. In soilless systems, cellulose hydrogels accelerated germination and improved plant development compared with control substrates. In soilless pea cultivation, HG-WP increased total biomass and survival from 56.7% to 79.3%. During basil cultivation in soil, cellulose hydrogel increased plant survival by 13.3% and mean biomass by 10.5% compared with the control. The results demonstrate the potential of cellulose hydrogels as biodegradable soil amendments and soilless substrates for short-cycle crop cultivation, outperforming the commercial polyacrylate hydrogel as an independent soilless substrate. Full article

Hydrogels have gained prominence as a class of biomaterials in biomedicine due to their excellent biocompatibility, biodegradability, and high water retention. Among them, hydrogels derived from natural polysaccharides sourced from plants, animals, and microbes are attracting growing interest due to their renewable nature, low toxicity, low immunogenicity, and diverse functional properties. While several recent reviews have addressed polysaccharide-based hydrogels, they have largely focused on isolated aspects—such as 3D bioprinting formulations, double-network mechanical reinforcement, rheological behavior, or single-source polysaccharides—without establishing an integrated framework that links raw material selection, structural diversity, chemical modification, and crosslinking design to clinical translation. This review distinguishes itself by providing a systematic, end-to-end perspective that spans from the structural diversity of plant- and microbe-derived polysaccharides through recent advances in chemical modification and novel cross-linking strategies, to the fine-tuning of physicochemical properties for enhanced therapeutic outcomes. This article provides an overview of the progress made in the emerging biomedical applications and material design of natural polysaccharide hydrogels in terms of raw material selection, chemical modification, cross-linking mechanisms, and functional utilization. It aims to fully explore the potential of these materials and promote integration into advanced biomedical practices. Full article

The increasing prevalence of antimicrobial resistance (AMR) has promoted the development of advanced biomaterials capable of overcoming the limitations of conventional antibiotics. In this context, metal nanoparticle hybrid hydrogels (MNHHs) have emerged as multifunctional platforms that integrate the high water-retention capacity and biocompatibility of hydrogels with the antimicrobial properties of metallic nanoparticles (MNPs). This review critically analyzes recent advances in the design, physicochemical properties, antimicrobial mechanisms, and biomedical applications of these systems. Current evidence demonstrates that MNHHs can achieve antimicrobial efficiencies above 98–99%, with minimum inhibitory concentrations as low as 0.78 µg mL⁻¹ and inhibition zones of up to 25 mm against clinically relevant pathogens. Furthermore, the incorporation of MNPs significantly improves the mechanical properties of hydrogels and enables controlled and sustained metal ion release for periods of up to 14 days. Despite these promising results, important challenges remain regarding cytotoxicity, release control, the lack of experimental standardization, and the limited understanding of long-term biological effects. Overall, MNHHs represent a promising strategy for infection control, regenerative medicine, and controlled drug delivery; however, their clinical translation still requires the development of reproducible, safe, scalable, and highly biocompatible systems. Full article

To meet the demand for superabsorbent, long-acting water-retentive, and recyclable hydrogel materials in landscaping applications, a series of AG-PAA/DA composite hydrogels were prepared using agarose (AG) and polyacrylic acid (PAA) as the network backbone, incorporating different mass fractions (2–30%) of dopamine (DA) via free radical polymerization initiated by ultraviolet light. The effects of DA content on the chemical structure, morphology, thermal stability, mechanical properties, water retention behavior, swelling kinetics, and cyclic water absorption–desorption performance were systematically investigated. The results show that DA is successfully integrated into the AG-PAA network through hydrogen bonding, electrostatic interactions, and covalent crosslinking, forming an amorphous homogeneous system. Thermal stability increases with DA content (residual mass at 800 °C rises from 77% to 88%). Mechanical properties exhibit a trend of increasing stress but decreasing strain, with optimal toughness (~670 kJ/m³) achieved at 10 wt% DA. Water retention performance is environment-dependent: in pure water, water retention increases with higher DA content, whereas in soil the opposite trend is observed. The kinetics of swelling conform to the pseudo-second-order model. The hydrogel with 10 wt% DA exhibits an equilibrium water absorption of 50 g/g in 0.9% saline solution and 1060 g/g in deionized water, and after 20 swelling–deswelling cycles the capacity retention fluctuates by less than 5%, demonstrating excellent cyclic stability. Considering all properties, AG-PAA/DA-10 is identified as the optimal formulation. This hydrogel combines high water absorption capacity, good environmental adaptability, and recyclability, showing great promise for water-saving irrigation in landscaping. Full article

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

Aqueous zinc-ion batteries are promising for large-scale energy storage due to their intrinsic safety, low cost, and environmental friendliness. However, their practical application is severely impeded by water-induced parasitic reactions and uncontrollable dendrite growth at the anode interface. Furthermore, the freezing of aqueous electrolytes at subzero temperature restricts their all-weather viability. Herein, we report a hydrogel electrolyte with interfacial regulation capabilities. By optimizing interfacial ion transport, the hydrogel electrolyte guides uniform Zn²⁺ deposition, effectively mitigating parasitic reactions and dendrite growth while enabling exceptional low-temperature tolerance. Consequently, the symmetric Zn//Zn cell using the hydrogel electrolyte delivers ultra-high cycling stability for 4000 h at 0.5 mA cm⁻² under −30 °C. When assembled into full cells, the Zn//NH₄V₄O₁₀ configuration operates stably for 4000 cycles at 5 A g⁻¹, exhibiting outstanding capacity retention. Furthermore, the assembled flexible pouch cell maintains 86% of initial capacity after 900 cycles at 3 A g⁻¹. Notably, the pouch cells demonstrate reliable operation and structural integrity under severe conditions, such as ice baths, bending, and piercing. This work provides an effective strategy for durable, wide-temperature, and intrinsically safe flexible aqueous energy storage systems. Full article

This study focused on a three-dimensional cross-linked hydrophobic association (PS) hydrogel framework. Phytic acid (PA) was selected as both a dopant and an antifreeze agent, and it was combined with an ethylene glycol/water binary solvent to construct a dual antifreeze system. The resulting composite conductive hydrogel, E/PS/PA-PPy, exhibited synergistically enhanced electrical conductivity, mechanical strength, and antifreeze properties. At a PA concentration of 0.1 M, a structurally uniform and ordered three-dimensional network was formed. The PS/PA-PPy hydrogel exhibited an elongation at break of 2595.7% and a high conductivity of 1.8 S/m, while maintaining excellent flexibility and adhesion. Owing to the synergistic antifreeze effect, the freezing point of the E/PS/PA-PPy hydrogel was reduced to −42.3 °C, and after 35 days of room-temperature storage, the weight loss was less than 7%, indicating outstanding water retention. The assembled flexible strain sensor exhibited a sensitivity of 2.09, with response and recovery times both less than 0.25 s. Notably, it exhibited good cyclic stability and accurately monitored human movements. Furthermore, the sensing performance remained stable without significant attenuation even at −20 °C. The results demonstrate the broad application prospects of the hydrogel in flexible electronics such as wearable health monitoring systems and human–machine interfaces in extreme environments. Full article

Conductive hydrogels are attractive for flexible electronics, but their practical use is often limited by resistance drift during repeated deformation and performance degradation at low temperatures. Here, core–shell polyaniline-coated polyacrylonitrile (PANi@PAN) electrospun nanofibers were incorporated into a polyacrylamide/hydroxypropyl cellulose (PAM/HPC) hydrogel matrix to construct a hybrid conductive network. The PANi shell serves as an electronic pathway alongside ionic conduction in the hydrated polymer network, leading to markedly improved electromechanical stability. The resistance drift is about 11% after 2000 stretching–relaxation cycles at 0–100% strain, about 12 times lower than that of the nanofiber-free hydrogel. Stable electrical responses are maintained under large deformation, with a resistance drift as low as 3.3% over a strain range of 0–400%. The hydrogels show a conductivity of 0.32 S m⁻¹ while retaining high stretchability (>600%). An ethylene glycol/water binary solvent is used to suppress ice formation and improve moisture retention, allowing stable electromechanical performance at −15 °C over 500 cycles. The hydrogel also adheres reliably to human skin (about 10.25 kPa) and functions as a conformal strain sensor without extra fixation. Full article

Corneal defects are a major cause of vision loss and require rapid, biocompatible, and effective sealing methods to restore ocular integrity and prevent infection. Current clinical adhesives, such as cyanoacrylate and fibrin glue, are limited by problems such as poor biocompatibility and inadequate stability. This study presents the design and evaluation of a fast-curable polymer bioadhesive hydrogel, a corneal glue formulated for efficient sealing of corneal defects. Hydrogels were synthesized from natural and synthetic polymers, including polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl cellulose (CMC), optimized for rapid gelation (~45 s), robust adhesion (~15 kPa), and mechanical strength (tensile strength ~0.35 MPa and storage modulus G′ indicating strong elastic behavior). Physicochemical and rheological properties, including swelling behavior and optical transparency (>90% transmittance across 400–700 nm), were characterized, including gelation time, swelling behavior, and mechanical strength. In vitro biocompatibility was assessed using human corneal epithelial cells to evaluate cytotoxicity and cell adhesion. Ex vivo studies on human cadaveric corneas with full-thickness defects measured adhesive strength and sealing efficacy through burst pressure (~38 mmHg) and leakage tests, with comparisons to commercial fibrin and cyanoacrylate adhesives. The optimized corneal glue exhibited fast curing, robust adhesion, high water retention with minimal swelling, favorable viscoelastic properties, and excellent cytocompatibility effectively sealing corneal defects in ex vivo models. These results highlight its potential as a promising fast-curable bioadhesive for corneal wound repair and ocular surface restoration. Full article

Chitin-based hydrogels have emerged as a versatile and sustainable material with significant potential in biomedical, environmental, and energy applications. Derived from the abundant biopolymer chitin, these hydrogels exhibit exceptional biocompatibility, biodegradability, and tunable physicochemical properties. This review highlights advances in chitin-based hydrogels, focusing on solvent systems, crosslinking strategies, and structural modifications to enhance mechanical strength, swelling, and stimuli responsiveness. Key applications include wound healing, drug delivery, tissue engineering, and environmental remediation, where their high-water retention, enzymatic degradability, and eco-friendly nature are particularly advantageous. Furthermore, innovations such as nanoparticle incorporation and chemical derivatization (e.g., carboxymethylation, hydroxypropylation) have expanded their utility in energy devices and smart sensors. Despite these advances, challenges remain in optimizing the energy efficiency of production methods for industrial scalability. This review provides a comprehensive overview of the current state of chitin-based hydrogels, offering insights into future directions for research and development in this promising field. Full article

Managing excessive water production in oil fields during primary, secondary, or enhanced recovery remains challenging. It increases costs and reduces hydrocarbon recovery, particularly in reservoirs with high-conductivity pathways such as high-permeability zones and fractures. Hydrogels are commonly used for water blocking and retention; however, their effectiveness diminishes at higher flow rates due to mechanical weaknesses and structural limitations. These problems are intensified under harsh environmental conditions, including high temperatures, salinity, and hardness. In this study, we investigate how altering the molecular suprastructure of preformed particle gel (PPG) can improve its effectiveness in shear-responsive water-blockage treatments, particularly when traditional PPGs cannot control rising flow rates. We enhance the shear-responsive mechanical properties of a composite PPG by increasing the density and diversity of intermolecular interactions. We use two different strategies: first, incorporating cationic groups into the polymer backbone to form a polyampholyte network with stronger electrostatic interactions; second, adding a linear anionic polymer to generate a secondary interpenetrating network that can undergo a coil–stretch transition under thermal and shear stimuli, thereby enhancing its own solvation and whole-network expansion. Molecular simulations provide an interpretation of the experimentally observed shear-thickening response and enhanced disproportionate permeability reduction at high flow rates. The water residual resistance factor of the improved PPGs deviates from the typical shear-thinning power-law behavior (n < 1) observed in conventional PPG, showing shear-thickening (n > 1). Tests reveal a strong ability to preferentially reduce water flow over oil, with Disproportionate Permeability Reduction increasing from 8 to 117 in the high-flow-rate zone. The enhanced strength and thermal stability also improve resistance to washout under high-pressure gradients. This research provides a novel approach to tailoring the microscopic architecture of PPGs to achieve selective, robust water blockage, offering a high-efficiency solution for complex reservoir environments. Full article

Background: Artemisia annua L. is a medicinal plant with documented antimicrobial, antioxidant, and anti-inflammatory properties. Although widely studied for internal therapeutic applications, its topical use—especially in hydrogel-based systems—has not been thoroughly investigated. The aim of this study was to develop sodium alginate hydrogels containing Artemisia annua extract, supplemented with hyaluronic acid and dexpanthenol, and to evaluate their physicochemical characteristics as well as their biological activities in vitro and in vivo. Methods: Select bioactive constituents of the Artemisia annua extract were quantified using liquid chromatography coupled with electrospray ionization mass spectrometry (LC-ESI-MS). Hydrogels were prepared by cross-linking sodium alginate with a calcium carbonate–glucono-delta-lactone system and were formulated with or without hyaluronic acid and dexpanthenol. Physicochemical evaluations included measurements of moisture content, water-retention capacity, gelation time, and pH. The hydrogel microstructure was examined by scanning electron microscopy (SEM). Antioxidant activity was assessed using three methods: the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, the ferric reducing antioxidant power (FRAP) assay, and the cupric reducing antioxidant capacity (CUPRAC) assay. Biocompatibility and regenerative effects were analyzed using cell viability assays and an in vitro scratch wound model on human keratinocyte cells. In vivo wound-healing efficacy was examined in rats with full-thickness skin excisions. Results: The extract contained high levels of methylated flavonoids and sesquiterpenes characteristic of Artemisia annua. Hydrogels supplemented with hyaluronic acid and dexpanthenol exhibited improved hydration stability and higher porosity. All formulations demonstrated measurable antioxidant activity, and those containing hyaluronic acid showed the strongest effects. The preparations were biocompatible and enhanced keratinocyte migration in vitro, with the combined hyaluronic acid–dexpanthenol formulation promoting the fastest wound closure. In vivo, Artemisia annua hydrogels accelerated wound healing by two to three days compared with untreated wounds. Conclusions: These results confirm the promise of Artemisia annua hydrogels for topical wound care and highlight the beneficial contributions of hyaluronic acid and dexpanthenol to their structural and therapeutic performance. Full article

Water scarcity, rapid soil moisture loss, and high evaporative demand severely limit vegetable production in arid regions such as Qatar. Sustainable soil amendments that enhance water retention and stabilize plant water status are therefore critical for improving productivity. This study evaluated a biodegradable hydrogel synthesized from date-palm leaf cellulose using a sodium alginate crosslinking method and assessed its effects on soil hydro-physical properties and tomato (Solanum lycopersicum L.) performance under arid conditions. A pot experiment was conducted under semi-controlled conditions using a single-factor randomized complete design with three hydrogel rates (0, 1, and 2% w/w) and three replications, with one plant per pot. All treatments received the same seasonal irrigation depth, scheduled when soil moisture declined to approximately 60–65% of field capacity. The hydrogel exhibited rapid hydration behavior, reaching equilibrium within 30–60 min with a swelling ratio of 5.659 g g⁻¹, corresponding to a water uptake of 465.9%, and SEM analysis revealed a porous internal structure favorable for water retention. At 1 and 2% application rates, hydrogel significantly reduced bulk density, increased total porosity and field capacity, and maintained higher soil moisture across irrigation cycles. Tomato plants grown in hydrogel-amended pots showed substantial gains in fresh biomass and root length, together with higher chlorophyll content, leaf nitrogen concentration, and relative water content. Water use efficiency improved significantly at 1% hydrogel, whereas the 2% rate showed a positive but non-significant trend. Overall, the results demonstrate that hydrogels derived from date-palm waste can enhance soil water retention, plant physiological status, and tomato productivity, offering a locally relevant strategy to improve agricultural resilience in arid environments. Full article

The growing need for ecologically sound and ethical protein sources has contributed to the development of meat analogs (MAs) and restructured meat products (RMPs). Next generation MA and RMP production requires sustainable structuring techniques to imitate the physical, chemical, and sensory characteristics of conventional meat. Innovative gelling techniques are essential for attaining optimal texture, chewiness, and structural firmness in MAs and RMPs. Food gels can modulate water and fat retention, as well as the physical and mechanical characteristics of MA and RMP. Different gelling systems such as hydrogels, emulsion gels, oleogels, and hybrid gels contribute to texture formation, water and fat retention, juiciness, and structural integrity, which are essential for mimicking conventional meat. The role of gels as key structuring elements is integrated with advanced processing technologies such as high-moisture extrusion and 3D printing. This review discusses how protein, polysaccharide, lipid, and hybrid gelling techniques facilitate the development of MAs and RMPs with enhanced texture, sensory quality, nutritional value, and sustainability. Advanced structuring techniques, such as high-moisture extrusion, shear cell processing, and 3D printing, are explained regarding their integration of tailored gels (hydrogels, emulsion gels, oleogels, and hybrid gels) to fabricate imitated meat structures. Moreover, this article investigates the sensory and nutritional ramifications of various gelling techniques, spanning their role in juiciness and flavor composition. This review emphasizes significant research deficiencies and suggests more extensive future studies to facilitate the further development of economically viable and sustainable MAs and RMPs. Full article