Search Results (627)

Polysaccharide-based hydrogels represent promising platforms for the development of bioactive wound dressings due to their biocompatibility, bioadhesive properties, and ability to maintain a moist environment at the wound interface. In this study, polymeric films were developed from natural polysaccharides incorporating olive mill wastewater (OMW) as a natural antibacterial agent. Chitosan (medium molecular weight), sodium alginate, sodium hyaluronate, and xanthan gum were selected to prepare hydrogel formulations either as single polymers or binary mixtures. Hydrogels were prepared by aqueous dispersion under magnetic stirring and subsequently converted into films using a solvent casting method. The resulting films were characterized in terms of rheological behavior, pH, morphology, thickness and water content. The obtained hydrogel films showed good casting ability, producing smooth and homogeneous matrices with adequate deformability and skin adhesion. Furthermore, they demonstrated a suitable capacity to absorb and retain water, mimicking the management of wound exudate. OMW was incorporated into the hydrogel formulations as a source of phenolic compounds with well-known antioxidant and antimicrobial properties. The presence of these bioactive compounds provides the films with potential antibacterial and antibiofilm activity against clinically relevant multidrug-resistant staphylococcal strains. These findings suggest that OMW-loaded polysaccharide hydrogels represent a promising and sustainable strategy for the development of antibacterial films for wound healing applications. Full article

Chitosan, produced through deacetylation of chitin from crustacean byproducts and, increasingly, fungal biomass and insects, is attracting food-sector interest because it combines antimicrobial activity, antioxidant capacity, biodegradability, and film-forming behavior in a single polymer. This review discusses how source, molecular weight (MW), degree of deacetylation, solubility, and charge density shape its performance in food systems. The paper then follows the main technological routes now tested or used: edible films and coatings, hydrogels, cryogels, nanoparticles, microcapsules, and hybrid matrices. These formats can protect fresh produce, meat, poultry, fish, seafood, and dairy foods, while also supporting beverage clarification, emulsion control, release of natural antimicrobials or antioxidants, and freshness monitoring in active or intelligent packaging. The evidence indicates strong promise, especially where microbial growth, lipid oxidation, moisture transfer, and short shelf life remain limiting factors. Yet, wider industrial use is still slowed by water sensitivity, sensory effects, raw-material variation, cost, process scale-up, and regulatory alignment. Future work should move beyond laboratory efficacy and address reproducible production, food-specific validation, and consumer acceptance. Full article

Hydrogel-based sensors have emerged as transformative soft-sensing platforms, featuring tissue-matched compliance, high water content, stimuli responsiveness, and chemical tunability, properties which are unachievable with conventional rigid sensors. Despite substantial advances, the existing reviews focus on individual polymer categories, discrete transduction mechanisms, or targeted standalone applications, failing to establish an integrated pipeline from material design to final sensing performance. This review fills these crucial gaps by systematically correlating polymer chemistry, crosslinking tactics, and fabrication protocols with the selection of transduction mechanisms and resultant sensing performance across biomedical and environmental fields. We conduct a critical assessment of natural and synthetic polymers together with chemical, physical, and hybrid composite crosslinking methodologies. Multiple sensing modalities, including piezoresistive, capacitive, thermogalvanic, electrochemical, colorimetric, ratiometric fluorescence, and piezoionic sensing are elaborated alongside representative quantitative performance parameters. Emerging platforms, including self-powered thermogalvanic sensors, SERS-integrated biosensors, and MXene/MOF composites, are highlighted as underexplored frontiers. In addition, persistent bottlenecks including dehydration-derived signal drift, inferior long-term operational stability, unsatisfactory target selectivity, and obstacles toward large-scale manufacturability are rigorously analyzed. Ultimately, this review constructs a holistic unified framework bridging polymer molecular design, fabrication engineering, signal transduction, and practical end-use applications, laying a clear developmental roadmap for next-generation flexible and smart hydrogel-based sensing systems. Full article

Nature offers a robust conceptual framework for designing next-generation adaptive, multifunctional sensing systems. Also, in sensing systems, Trojan materials add a functional dimension to the microstructure, enabling the development of high-performance humidity sensors without interfering with their macrostructure. Thus, based on a brief overview of how inspiration from plants, animals, and membranes can be used to engineer high-performance platforms for environmental humidity monitoring, combined with the functional dimension of Trojan materials, this review presents a critical framework detailing the key developments in the main categories of self-sensing materials within the scope of humidity sensors. The review addresses electronically and ionically conductive polymers, polymer composites with dispersed active fillers, and hydrogel-based or other water-compatible systems. Additionally, commercially available sensors are described, and the main challenges and future directions are identified. Full article

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

The unique anatomy and physiological barriers of the human eye—particularly rapid tear turnover and limited corneal permeability—present significant obstacles to achieving effective topical drug delivery. In response to these constraints, biopolymer-based extended-release systems have emerged as a promising and transformative class of ocular therapeutics. This review provides a comprehensive overview of recent advances in natural biopolymers, including polysaccharides and protein-derived polymers, for application on the ocular surface. These materials exhibit advantageous characteristics such as mucoadhesion, biocompatibility, and stimuli-responsive behavior, which collectively enhance precorneal residence time and enable controlled, sustained drug release. We further discuss diverse delivery platforms—ranging from in situ forming hydrogels and mucoadhesive nanoparticles to drug-eluting contact lenses and microneedle-based systems. In addition, we highlight how the integration of nanotechnology and bioinspired scaffolds can augment the delivery efficiency of therapeutic agents to ocular tissues. Overall, this review underscores the ongoing transition from conventional topical eye drops to sophisticated, functionalized delivery systems capable of maintaining therapeutic drug levels while simultaneously supporting tissue repair and wound healing. Finally, we outline the remaining challenges in clinical translation and consider the future potential of smart, responsive biopolymer systems in advancing the treatment of both anterior and posterior segment diseases. Full article

Background/Objectives: Modern dentistry increasingly requires biomaterials that not only replace damaged tissues but also actively regulate healing processes, modulate inflammation, and provide controlled delivery of therapeutic agents under the complex physicochemical conditions of the oral cavity. This review aims to analyze the potential of PCHs, particularly methacryloyl gelatin (GelMA), as multifunctional platforms for drug delivery in dental applications. Methods: This review provides a structured narrative synthesis of the literature, focusing on the physicochemical, biological, and translational aspects of photocrosslinkable hydrogels in dentistry. Special attention was given to the key functional requirements for hydrogels used in dentistry, including adhesion in a wet environment, antimicrobial properties, and the ability to provide sustained and localized release of active compounds. Natural, synthetic, and semi-synthetic polymers were comparatively evaluated to justify the selection of GelMA as a leading platform due to its tunable mechanical properties, biocompatibility, and photopolymerization capacity. The review also analyzes mechanisms of drug release activation and provides a comparative assessment of commonly used photoinitiators, including Irgacure 2959, lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP), and camphorquinone, with emphasis on their cytocompatibility with oral tissues. Results: Applications of these hydrogels in endodontics, periodontology, peri-implantitis therapy, and regeneration of bone and dental pulp are summarized. Conclusions: Overall, photocrosslinkable GelMA-based hydrogels (PC-GelMA) represent promising multifunctional platforms for localized drug delivery and regenerative strategies in modern dentistry. Full article

With an increased number of chronic wounds and accidents worldwide, the need for advanced wound care approaches has been urgent. In this regard, sprayable hydrogel dressings have emerged as an innovative biomaterial due to their unique rheological properties, minimally invasive operation capabilities, excellent adaptability to irregular surfaces, and in situ rapid gelation. This review focused on elaborating the main materials used to construct sprayable hydrogels, including natural polymers and synthetic polymers, and discussing their respective molecular structures, physicochemical properties, advantages, and challenges in formulation design. This review also explored the properties of sprayable hydrogels, including sprayability, adhesion performance, mechanical strength, moisture absorption, breathability, biocompatibility, and degradability. The mechanisms of their controllable gelation through chemical crosslinking and physical crosslinking strategies were analyzed. Subsequently, the applications of sprayable hydrogels in wound areas, including diabetic wounds, infected wounds, postoperative adhesions, burn wounds, and joint wounds, were comprehensively reviewed. The challenges and future developments in wound healing were clarified to provide valuable references for promoting interdisciplinary research and the clinical translation of sprayable hydrogels. Full article

Polymer-based dressings constitute an important class of macromolecular biomaterials enabling controlled drug delivery and enhanced wound healing performance. This review summarizes recent advances in the design, fabrication, and functionalization of polymer dressings, with emphasis on natural and synthetic polymer systems applied in biomedical topical and transdermal drug administration. Key material properties, including biocompatibility, mechanical stability, porosity, and degradation behavior, are discussed in relation to drug loading capacity and release kinetics. Current fabrication strategies, such as electrospinning, hydrogel formation, casting, and multilayer assembly, are critically evaluated with respect to structural control and scalability. Particular attention is given to antimicrobial and stimuli-responsive platforms capable of dynamic interaction with the wound microenvironment. Furthermore, challenges related to long-term stability, regulatory requirements, and clinical translation are addressed. By integrating recent experimental findings, this review highlights essential structure–function relationships governing polymer dressing performance and provides design guidelines for next-generation macromolecular topical and transdermal care systems with improved multifunctionality and clinical applicability. Full article

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

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

Alginate-based hydrogels are well-known materials for drug delivery. However, their sensitivity towards chelators and burst release remain concerns. Polyelectrolyte coatings have been proposed to control drug release from hydrogels, but it remains unclear how the types of coating influence the release kinetics of drugs with varying ionic properties. Hence, we explored combinations of natural (chitosan, alginate) and synthetic (polyethyleneimine [PEI], polyacrylic acid [PAA]) polyelectrolytes to modulate the release kinetics of alginate-based hydrogel beads. Rhodamine B (RhB, cationic) and trypan blue (TB, anionic) were used as model drugs. PAA resulted in a less porous coating, and PEI effectively reduced swelling. While uncoated beads showed burst release, polyelectrolyte coatings slowed release to varying degrees. Chitosan+alginate and chitosan+PAA coatings showed limited impact on RhB release. In contrast, PEI+alginate and PEI+PAA coatings significantly reduced RhB release from 86% (uncoated) to 61% and 6% after 4 days, respectively. Alginate–TB displayed inherently slower release across all systems, with polymer coatings further reducing cumulative release from 49% (uncoated) to 7% in PEI+PAA-coated beads. Overall, polyelectrolyte coatings had a greater influence on the anionic payload, and PEI+PAA-coated beads emerged as promising carriers for controlled release of both cationic and anionic drugs. Full article

Chronic wounds, diabetic foot ulcers, venous leg ulcers, and pressure injuries affect millions of patients worldwide and cost healthcare systems in the order of $150 billion annually, yet treatment options have changed less than the scale of the problem would suggest. Biofilm formation, documented in up to 78% of chronic wounds, is a central cause: bacteria embedded in extracellular polymeric matrices tolerate antimicrobial concentrations up to 1000-fold higher than planktonic cells and sustain a chronic inflammatory state that actively prevents tissue repair. Hydrogels, crosslinked polymer networks with high water content and tunable physicochemical properties, have been widely studied as platforms for addressing these challenges, though the distance between laboratory results and clinical practice remains considerable. While recent reviews have summarized hydrogel materials or antimicrobial strategies in isolation, this review takes a different approach: we treat infection, biofilm persistence, and impaired regeneration as interconnected processes that must be addressed simultaneously, and we examine biofilm management as a distinct therapeutic target rather than merely a subset of antimicrobial delivery. We analyze hydrogel-based wound care across three integrated domains: design principles (natural, synthetic, and hybrid polymer systems; crosslinking strategies; and stimuli-responsive architectures), antimicrobial delivery (silver, antibiotics, antimicrobial peptides, natural agents, and controlled-release systems), and biofilm management (nanoparticle-mediated disruption, enzymatic EPS degradation, photodynamic approaches, quorum-sensing inhibition, and anti-adhesive surface engineering). For each area, we critically evaluate what the preclinical evidence supports, where it falls short, and what would be needed to bridge the gap to clinical application. Translation remains uneven. Among the many FDA- and EMA-cleared hydrogel dressings currently in clinical use, most are simple moisture-retaining or silver-containing formulations, while the multifunctional systems that dominate the research literature are at earlier stages of development. We discuss the main translational priorities, including more predictive preclinical models, long-term nanomaterial safety, harmonized outcome reporting, manufacturing scalability, and health economic evidence, as areas where further work can meaningfully accelerate clinical adoption. Full article

Soil degradation in both agricultural and urban environments is accelerating due to intensive land use, plastic pollution, construction practices, and climate change, threatening ecosystem stability, food security, and carbon storage capacity. This review synthesizes current advances in biopolymeric materials as regenerative alternatives to conventional soil management approaches. Biopolymers derived from natural sources—including polysaccharides, proteins, and lignin-based compounds—are examined for their multifunctional roles in improving soil structure, enhancing water retention, optimizing nutrient delivery, stabilizing slopes, and supporting pollutant immobilization. Recent developments highlight the emergence of stimuli-responsive hydrogels, controlled-release fertilizer matrices, and composite soil conditioners capable of simultaneously addressing water stress, salinity, erosion, and contamination. In parallel, biodegradable agricultural films and in-soil degradable materials offer pathways to reduce microplastic accumulation while maintaining agronomic performance. Beyond agriculture, bio-based construction materials and bio-receptive design strategies extend biopolymeric interventions into the built environment, promoting soil permeability, microbial diversity, and circular material flows. The review emphasizes the need for context-specific formulation, long-term field validation, and life-cycle assessment to ensure environmental safety and scalability. By integrating soil science, polymer chemistry, and regenerative design, biopolymeric systems are described here as tools for restoring soil health and fostering resilient urban–rural ecosystems under conditions of environmental change. Full article

Hydrogels, particularly those based on polymer networks, exhibit complex mechanical behaviors arising from the interplay between network architecture, molecular interactions, and external stimuli. In particular, their viscoelasticity, energy dissipation, and nonlinear mechanical responses arise from the dynamic nature of crosslinking and multiscale relaxation processes. This review provides a comprehensive overview of hydrogel mechanics from a multiscale perspective, covering viscoelastic behavior, relaxation dynamics, energy dissipation mechanisms, nonlinear deformation, and fracture properties. We summarize recent advances in experimental characterization, including bulk rheology and single-molecule force spectroscopy, and discuss how molecular-level interactions, bond kinetics and mechanochemical processes contribute to macroscopic mechanical performance. In addition, theoretical models and constitutive frameworks describing transient and dynamic polymer networks are critically evaluated to bridge microscopic dynamics with bulk responses. Emerging strategies that integrate dynamic bonding and force-responsive elements are also discussed in the context of tailoring mechanical adaptability and functionality. Finally, we outline current challenges and future directions toward the rational design of hydrogels with tunable viscoelasticity, enhanced mechanical robustness, and programmable mechanical functions. Full article