Chitosan-based self-healing hydrogel dressing for wound healing

Hierarchical chitin and chitosan-derived heterostructural nanocomposites: From interdisciplinary applications to a sustainable vision

Natural biopolymeric nanomaterials are highly prioritized and indispensable for industrial production and human use due to their exceptional features. In recent years, the development of bioinspired materials has rapidly advanced, driven by their outstanding qualities and versatile applications. Among these, chitin and chitosan stand out for their biodegradability, biocompatibility, and hierarchical structures, captivating researchers worldwide. In order to ameliorate the characteristics of these materials, integrating them with complementary components such as polymers, organics, and nanomaterials to create multifunctional chitinous bio-composites has become increasingly important. This review highlights recent progress in the development of these composite biomaterials, emphasizing biomimetic design, synthesis methodologies, and applications in drug delivery, cancer therapy, tissue engineering, wound healing, antimicrobial activity, food safety, natural bio-adhesives, and various industrial uses, alongside their ecological balance on Earth within a sustainable vision. Additionally, the discussion also addresses ongoing challenges and explores potential prospects for advancing these innovative biocomposites.

Nanoscale cuttlebone-doped PVA/SA hydrogel with hemostatic and antibacterial properties

Effective wound management remains a major clinical challenge, especially in preventing infections and promoting rapid healing. However, traditional wound dressings often lack multifunctionality, limiting their ability to support hemostasis and antibacterial protection. To address this challenge, in this work, a novel wound dressing was developed utilizing nano-cuttlebone particles, which are rich in calcium carbonate and chitin, to enhance hemostatic and antimicrobial functionality. The dressing, composed of polyvinyl alcohol, sodium alginate, and nano-cuttlebone, addresses the need for advanced wound care solutions. The particle size distribution of the powder was evaluated using a laser particle size analyzer, and the particle size of the nano-cuttlebone was around 75 nm. The drug release experiment showed that the drug release of nano cuttlebone hydrogel was 1.4 times that of micro cuttlebone hydrogel in 48 h. The antibacterial activity of the nano-cuttlebone-doped dressing against S. aureus was 97.32 % and against E. coli was 99.99 %. The cell scratch test showed that the nano-cuttlebone hydrogel gradually migrated to the central area, and its migration rate was 61.43 % after 12 hours. The hydrogel also demonstrated excellent hemostatic ability in a mouse liver injury model and could rapidly stop bleeding within 1 min. In a full-thickness wound model, the nano-cuttlebone hydrogel enhanced collagen deposition and promoted faster wound closure. This study highlights the potential of marine biomaterials for developing multifunctional wound dressings to improve patient outcomes.

State-of-the-art in natural hydrogel-based wound dressings: Design, functionalization, and fabrication approaches

Natural hydrogel-based wound dressings, synthesized from biopolymers such as chitosan, sodium alginate, and cellulose, are gaining recognition in wound care due to their ability to promote healing through biocompatibility, moisture retention, and biodegradability. These materials foster an ideal healing environment by supporting cell proliferation and tissue regeneration while providing a protective barrier against infection. For chronic or infected wounds, enhancing the therapeutic performance of these hydrogels is essential. This review critically evaluates advanced functionalization strategies, including chemical modifications to optimize hydrogel properties, the incorporation of bioactive agents like growth factors and antimicrobial compounds, and the development of stimuli-responsive hydrogels that adjust to environmental cues such as pH, temperature, and enzymatic activity. Furthermore, fabrication techniques-such as solution casting, freeze-drying, electrospinning, and 3D printing-are discussed for their potential to generate tailored dressings with specific mechanical properties and bioactive capabilities. By highlighting key innovations and challenges, this review provides a comprehensive roadmap for the design, functionalization, and fabrication of natural hydrogel-based wound dressings, identifying critical areas for future research and development.

Synthesis and characterization of hydroxyethyl chitosan as a functional pharmaceutical excipient

This study aims to develop an excellent pharmaceutical excipient based on crosslinked hydroxyethyl chitosan (G-HECTS(GA)), designed to exhibit high intrinsic viscosity and superior moisture absorption and retention properties for wound healing applications. Hydroxyethyl chitosan (HECTS) was synthesized from chitosan through a derivatization reaction with bromoethanol under alkaline conditions, achieving a maximum solubility of 6.8 ± 0.2 g/100 g water. The HECTS was further crosslinked with glutaraldehyde (GA) to produce G-HECTS(GA). Structural characterization of the product was performed using Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Key parameters, including crosslinker dosage, reaction time, temperature, and stirring speed, were optimized to evaluate their effects on intrinsic viscosity. The physicochemical properties and wound healing efficacy of G-HECTS(GA) were systematically assessed in a rat wound model. Under optimal conditions (35 °C, 25 μL GA, 18 h reaction time), the crosslinked product demonstrated an intrinsic viscosity of 1870 ± 70 mL/g, a moisture retention rate of 39 % ± 3 %, and a moisture absorption rate of 39.1 % ± 0.7 %. G-HECTS(GA) rapidly formed a stable film on wound surfaces, effectively absorbing exudates and promoting wound healing. The material exhibited excellent stability, biocompatibility, and antibacterial activity, along with significant anti-inflammatory effects. These properties highlight the potential of G-HECTS(GA) as a high-performance pharmaceutical excipient for hemostatic spray formulations, offering a promising solution for mucosal wound repair and related biomedical applications.

Construction of AgNPs-loaded oriented hydrogel based on Periostracum Cicadae chitosan by electro-assembly for rapid hemostasis and wound healing

Oriented hydrogels have been recognized for their ability to promote cell proliferation and enhance wound repair. Chitosan, valued for its biocompatibility and biodegradability, is widely used in hydrogel preparation. However, chitosan derived from Periostracum Cicadae ("Chantui") has not been explored for creating antibacterial-oriented hydrogels. In this study, we successfully developed a Periostracum Cicadae chitosan-based oriented hydrogel (O-CH) using an electro-assembly method. The O-CH hydrogel exhibited superior hemostatic performance and mechanical strength, with stress levels 7.6 times higher than those of traditional alkali-neutralized hydrogels. Subsequently, silver nanoparticles (AgNPs) were formed in situ on the O-CH hydrogel without the need for additional reducing agents or stabilizers, yielding O-CH@Ag20, which exhibited excellent biocompatibility and enhanced antibacterial properties. In an S. aureus-infected full-thickness rat skin defect model, O-CH@Ag20 reduced bacterial counts at the wound site by 6-fold compared to the gauze group on day 3 and achieved a 97 % wound healing rate by day 10, versus 75 % in the gauze group. Histological analysis revealed that O-CH@Ag20 regulated angiogenesis, collagen deposition, and fibroblast differentiation into myofibroblasts, thereby accelerating wound contraction during remodeling. This study presents a novel approach to addressing clinical challenges in infected wound healing using Periostracum Cicadae chitosan-based antibacterial hydrogels.

Investigation of neem-oil-loaded PVA/chitosan biocomposite film for hydrophobic dressing, rapid hemostasis and wound healing applications

The present work aims to develop a hydrophobic dressing with a blood-repellent surface that achieves fast clotting without blood loss, having antibacterial properties, clot self-detachment, and superior wound healing activity. For these reasons, a novel approach was applied by producing a hydrophobic film made of PVA, chitosan, and neem seed oil (NSO). The film had the necessary hydrophobicity, mechanical strength, stability and was able to transmit water vapor to be suitable for the wound skin surface and demonstrated faster blood clotting (BCI = 91.44 % in 5 min and 85.22 % in 10 min). The proportion of red blood cells (2.78 %) and platelets (17.33 %) attached to the film proved its excellent hemostatic activity. It was anti-adhesive, created spontaneous clot detachment, and exhibited antibacterial properties at the wound site, as evidenced by in vivo testing. Moreover, in vivo testing and histopathological findings showed enhanced wound healing activity, greater re-epithelialization, and decreased granulation tissue. Additionally, the film's eco-friendliness was evaluated using a soil burial degradation test, and the results show that it deteriorated into the soil but did so slowly because of its hydrophobic property. Thus, PVA/CS/NSO composite film may be a green biomedical material for hemostasis and wound healing.

Strong and tough chitosan-based conductive hydrogels cross-linked by dual ionic networks for flexible strain sensors

Conductive hydrogels made of eco-friendly materials have been concerned in the field of flexible electronic devices (FEDs). Great efforts have been made to improve mechanical properties of conductive hydrogels, which are still unsatisfactory for natural polymer hydrogels. Herein, a strategy to improve mechanical properties of chitosan-based hydrogels by constructing dual ionic networks via cations and anions is reported. Through the double crosslinking of high-valent cations (Al3+) and anions (SO42-) with the polymers, as well as the salting-out effect of salts, the resulting hydrogels have evolved tensile strength and toughness, which are up to 8 MPa and 28.4 MJ/m3, respectively. The reversible ionic networks play a vital role in tensile recovery, further leading to stability in the relative resistance change of the hydrogels under various deformation. The dual ionic crosslinked hydrogels possess moderate gauge factor (1.2-2.9) at tensile strain from 100 % to 400 %, which are sensitive to monitor human movements as flexible strain sensors. In addition, the hydrogels show perfect antibacterial activity against E. coli and S. aureus. Overall, this work provides an effective way to fabricate strong and tough conductive hydrogels based on chitosan for promising application of FEDs.

Berberine@AgNPs@Carboxylated chitosan hydrogel dressing with immunomodulatory and anti-biofilm properties promotes wound repair in drug-resistant bacterial infections

Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterial strain resistant to multiple antibiotics frequently encountered in clinical settings. Excessive antibiotic use has increased bacterial resistance, leaving a lack of effective treatments for MRSA infections. MRSA often colonizes the surface of skin wounds, resulting in chronic inflammation and protracted wound healing. The biofilm formation hinders the complete eradication of the bacteria, exacerbating the local inflammatory response and impeding wound healing. This study presents an innovative methodology for managing MRSA-infected skin wounds. The novel immunomodulatory hydrogel composed of Berberine, silver nanoparticles (AgNPs), and carboxylated chitosan (designated as Ber@AgNPs@CHI hydrogel) demonstrates enhanced therapeutic efficacy in a murine model of MRSA skin infection. This hydrogel is effective in eradicating MRSA and preventing biofilm formation. Furthermore, it modulates the local immune microenvironment by facilitating the transition of macrophages from the M1 to M2 phenotype and increasing the production of vascular endothelial growth factor (VEGF). These actions collectively facilitate the progression of the wound from the inflammatory to the proliferative phase, enhancing the early stages of wound healing. Hence, this safe and effective hydrogel mediates wound healing from multiple perspectives and targets, providing a new potential avenue for treating persistent infected wounds caused by clinical MRSA.

Gelatin-based adaptive injectable nanocomposite hydrogel for closure of irregular wounds and immunoregulation in diabetic wound healing

Chronic wounds are a major challenge in diabetic patients, exacerbated by disorders of blood perfusion and angiogenesis, bacterial infection, oxidative stress, and inflammation and immune imbalance. Bioactive hydrogels with multifunctional immunomodulatory properties offer promising solutions for diabetic wound management. However, many hydrogels lack adaptability and rely on costly cytokines, cell therapies, or drugs with side effects. This study introduces a novel gelatin-based injectable nanocomposite hydrogel (GelDE-OCS@MOF@Pl) for irregular wound closure and diabetic ulcer healing. This naturally derived macromolecular hydrogel exhibits exceptional biocompatibility and in situ molding capabilities, enabling effective closure and repair of irregular wounds. The GelDE-OCS@MOF@Pl hydrogel serves dual therapeutic functions by establishing a protective physical barrier while intelligently regulating polyphyllin (Pl) release in response to pH variations, thereby simultaneously eliminating bacterial pathogens, scavenging reactive oxygen species, and suppressing excessive inflammation for providing a suitable microenvironment for angiogenesis and epithelialization. This nanocomposite hydrogel effectively promotes diabetic wound healing through coordinated modulation of the wound immune microenvironment, demonstrating multifunctional therapeutic effects including antibacterial activity, oxidative stress alleviation, and anti-inflammatory action, thereby presenting a promising treatment strategy for chronic diabetic wounds.

A preliminary study on the promotion of wound healing by paeoniflorin carbon dots loaded in chitosan hydrogel

Due to poor angiogenesis under the wound bed, wound treatment remains a clinical challenge. Therefore, there is an urgent need for new dressings to combat bacterial infections, accelerate angiogenesis, and accelerate wound healing. In this study, we prepared carbon dots nanomaterial (PF-CDs) derived from traditional Chinese medicine paeoniflorin using a simple green one pot hydrothermal method. The average particle size of the CSs we prepared was 4 nm, and a concentration of 200 μg ml-1was ultimately selected for experiments. Subsequently, PF-CDs were loaded into the chitosan hydrogel to form a new type of wound dressing CSMA@PF-CDs hydrogel. CSMA@PF-CDs demonstrated positive biocompatibility by promoting a 20% increase in cell proliferation and strong antibacterial activity. In comparison to the control group, CSMA@PF-CDs enhanced the expression level of anti-inflammatory factors by at least 2.5 times and reduces the expression level of pro-inflammatory factors by at least 3 times. Furthermore, CSMA@PF-CDs promoted the migration of Human umbilical vein endothelial cells and increased vascular endothelial growth factor expression by 5 times. The results ofin vivoexperiments indicate that CSMA@PF-CDs significantly promoted the healing of back wounds in rats. These characteristics make it a promising material for repairing infected wounds and a potential candidate for clinical skin regeneration applications.

Construction of pH-Sensitive Multifunctional Hydrogel with Synergistic Anti-Inflammatory Effect for Treatment of Diabetic Wounds

Background/Objectives: A sustainable inflammatory response is a significant obstacle for diabetic wound care. In this study, the pH-sensitive multifunctional hydrogel ODex/BSA-Zn was fabricated via a Schiff base and coordination force for the first time. Methods: The hydrogel consisted of oxidized dextran (ODex), bovine serum albumin (BSA), and zinc ions (Zn2+) in the absence of an additional crosslinking agent. Results: The hydrogel showed excellent mechanical stability, fast self-healing ability, and significant anti-inflammatory effects, as demonstrated by the formation of dynamic covalent bonds between the aldehyde group (-CHO) of ODex and the amino group (-NH2) of BSA via the Schiff base reaction, as well as the metal-ion coordination reaction of Zn2+ with the imidazole ring of BSA. In a diabetic mouse full-thickness cutaneous defect wound model, the ODex/BSA-Zn hydrogel could effectively inhibit the inflammatory response and increase collagen deposition, thereby accelerating the transition of macrophage M1 to M2 and promoting wound closure. This study offers a promising therapeutic approach for managing long-term diabetic ulcers.

Review of self-healing polysaccharide-based hydrogels in tissue regeneration: Characterization methods and applications

The design of hydrogels with self-healing properties represents a significant advancement in the biomedical field. Polysaccharide-based self-healing hydrogels have garnered attention because of their unique attributes, including biocompatibility and biodegradability, as well as their ability to autonomously repair damage. Polysaccharide-based self-healing hydrogels consist mainly of crosslinked hydrophilic polymer networks that mimic the self-repair mechanisms of biological tissues. This review examines the self-healing mechanisms of polysaccharide-based hydrogels, evaluates their healing ability, and discusses characterization techniques to quantify their healing efficiency. In addition, the review highlights the advantages of self-healing hydrogels and discusses potential applications, particularly in the areas, such as medical dressings, drug delivery, and tissue regeneration. By addressing the challenges of self-healing hydrogels, these materials represent a promising frontier in the field of advanced biomaterials.

Advances in polymer nanomaterials targeting cGAS-STING pathway for enhanced cancer immunotherapy

Cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS)-stimulator of interferon genes (STING) pathway has been recognized as a promising target for cancer immunotherapy. Although various STING agonists have been developed, their clinical applications are still severely impeded by various issues, such as non-specific accumulation, adverse effects, rapid clearance, etc. In recent years, the emergence of nanomaterials has profoundly revolutionized STING agonists delivery, which promote tumor-targeted delivery, boost the immunotherapeutic effects and reduce systemic toxicity of STING agonists. In particular, polymer nanomaterials possess inherent advantages including controllable structure, tunable function and degradability. These properties afford them the capacity to serve as delivery vehicles for small-molecule STING agonists. Furthermore, the superior characteristics of polymer nanomaterials can enable their utilization as a novel STING agonist to stimulate anti-tumor immunity. In this review, the molecular mechanisms of cGAS-STING pathway activation are discussed. The recent development of small-molecules STING agonists is described. Then polymer nanomaterials are discussed as carriers for STING agonists in cancer immunotherapy, including polymersomes, polymer micelles, polymer capsules, and polymer nanogels. Additionally, polymer nanomaterials are identified as a novel class of STING agonists for efficient cancer immunotherapy, encompassing both polymer materials and polymer-STING agonists conjugates. The review also presents the combination of polymer-based cGAS-STING immunotherapy with chemotherapy, radiotherapy, phototherapy (both photodynamic and photothermal), chemodynamic therapy, and other therapeutic strategies. Furthermore, the discussion highlights recent advancements targeting the cGAS-STING pathway in clinically approved polymer nanomaterials and corresponding potent innovations. Finally, the potential challenges and perspectives of polymer nanomaterials for activating cGAS-STING pathway are outlined, emphasizing the critical scientific issue and hoping to offer guidance for their clinical translation.

Injectable carboxymethyl chitosan/konjac glucomannan/catechin hydrogel with free radical-scavenging, antimicrobial, and pro-healing abilities for infected wound repair

Wound management presents a significant clinical challenge, requiring advanced materials to support effective healing. This study reports the development of a multifunctional injectable hydrogel wound dressing (U-COC) composed of methacrylated carboxymethyl chitosan (CMCSMA), oxidized konjac glucomannan (OKGM), and (+)-catechin hydrate (CH). The formation of the U-COC hydrogel was driven by photo-initiated polymerization, dynamic reversible Schiff base bonds, and non-covalent forces (hydrogen bond interactions, π-π stacking, and hydrophobic interactions). The in vitro antioxidant and antimicrobial test results indicated that the U-COC hydrogel could effectively scavenge oxygen central free radical PTIO· (69.8 ± 0.3%) and nitrogen central free radical DPPH· (92.8 ± 0.7%), and exhibited excellent antimicrobial effects against E. coli (89.7 ± 3.9%) and S. aureus (91.4 ± 3.4%) due to the introduction of CH. Moreover, the as-designed hydrogel wound dressing was biosafe and biodegradable, demonstrating good adhesion, wound closure, self-healing properties, and shape adaptability. This hydrogel provided an advantageous microenvironment for cell proliferation, re-epithelialization, angiogenesis, collagen deposition, and tissue repair during infected wound healing. Therefore, the combination of CMCSMA, OKGM, and CH, along with the formation mechanism of the U-COC hydrogel, represents a novel advancement in wound management technology.

Supermolecular poly-N-acryloyl glycinamide/polyglutamic acid/Fe3+ hydrogel incorporated with bioactive small extracellular vesicles promote diabetic wound healing by suppressing ferroptosis

Poorly-controlled blood glucose frequently develop in diabetic wounds and hydrogel has been reported of great performance for diabetic wound healing. Consequently, we prepared poly-N-acryloyl glycinamide (PNAGA) and introduced polyglutamic acid (γ-PGA), Fe3+, small extracellular vesicles (sEVs) into PNAGA to form a dual physical cross-linking supramolecular hydrogel system (PFF) for diabetic wound healing. In this study, we successfully synthesized the PFF hydrogel and extracted the sEVs that were incorporated into PPF as PPF/sEVs. In our research, we find that PFF hydrogel possessed continuous porous structure and, exceptional resilience, excellent extensibility and flexibility, closely mimicking the mechanical performance of human skin. Moreover, the PFF/sEVs hydrogel could release sEVs, playing a critical role in wound healing. Our results showed PFF/sEVs hydrogel improved the wound healing characterized by shorter wound closure time and enhanced blood vessel density in vivo. Also, sEVs counteracted the inhibitory effects of high glucose on proliferation, migration, tube differentiation, malondialdehyde (MDA) and glutathione (GSH) levels, which may attribute to the inhibition of ferroptosis by influencing free fatty acids (FFA) metabolism in vitro. Our findings indicated that the low-cost, biocompatible, and multifunctional bioactive PFF supramolecular hydrogel loaded with sEVs hold tremendous application potential as a clinical platform for diabetic wound healing.

Multi-functional chitosan fiber-based dressings prepared by screen printing of baicalein and activated charcoal

In this study, chitosan needle-punched nonwovens (CS) was screen-printed with functional inks containing baicalein (Bai) and activated charcoal (AC) to prepare multifunctional dressings (AC + Bai@CS). The polyelectrolyte interaction between chitosan (matrix) and sodium carboxymethylcellulose (binder) facilitated the firm attachment of Bai and AC to the CS. Moreover, the screen-printed ink did not impact the surface hydrophilicity and the excellent air permeability (1837.5 ± 34.03 mm/s) of AC + Bai@CS. The printing of baicalein on the chitosan matrix resulted in a synergistic effect, leading to the AC + Bai@CS exhibiting enhanced antibacterial, antioxidant, and anti-inflammatory properties while maintaining cytocompatible characteristics. Furthermore, the deodorization rates of AC + Bai@CS against ammonia and acetic acid were 84.2 ± 1.6 % and 75.4 ± 1.1 %, respectively, indicating its potential deodorization effect on chronic wounds. This study presents a novel approach to developing multifunctional wound dressings via facile screen printing.

A novel strategy for addressing post-surgical abdominal adhesions: Janus hydrogel

Abdominal adhesions are a frequent complication after abdominal surgery, which can cause significant pain and burden to patients. Despite various treatment options, including surgical intervention and pharmacotherapy, these often fail to consistently and effectively prevent postoperative abdominal adhesions. Janus hydrogel is famous for its asymmetric characteristics, which shows great prospects in the prevention and treatment of abdominal adhesion. This review outlines the preparation methods, mechanisms of action, and key applications of Janus hydrogel in the prevention of postoperative abdominal adhesions. Furthermore, we examine the current limitations of the Janus hydrogel anti-adhesion barrier and explore potential future directions for its development.

NIR-activating glycyrrhizic acid/carbon nanozyme injectable polysaccharides-based hydrogels for promoting polymicrobial infected wound healing

The slow healing or non-healing of skin wounds caused by polymicrobial infections has become a serious problem in clinical wound treatment. Herein, we have developed a near-infrared (NIR) activating glycyrrhizic acid/carbon nanozyme injectable polysaccharides-based hydrogel (the CPCA hydrogel) for the synergistic treatment of polymicrobial infected wound. The CPCA hydrogel could undergo phase transition at a specific temperature and facilitate administration at the wound site. Additionally, under near-infrared light irradiation, the CPCA hydrogel could generate heat and promote the release of glycyrrhizic acid (GA) for achieving photothermal-drug synergistic treatment of multiple bacteria. Furthermore, the carbon nanozyme (CN) within the injectable polysaccharides-based hydrogel could mimic the activity of superoxide dismutase (SOD) and catalase (CAT) for enabling the removal of reactive oxygen species, effectively alleviating inflammation and promoting wound healing caused by polymicrobial infections. The results of in vitro antibacterial experiments demonstrated the excellent antibacterial effect of CPCA hydrogel on methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa. Furthermore, in vivo experiments confirmed that the hydrogels significantly reduced inflammatory responses and accelerated angiogenesis in polymicrobial infected wounds. Collectively, the CPCA hydrogel exhibited excellent antibacterial and anti-inflammatory properties, offering a novel strategy for developing new treatments for polymicrobial infections.

Using network analysis and large-language models to obtain a landscape of the literature on dressing materials for wound healing: The predominance of chitosan and other biomacromolecules: A review

We present an overview of the literature on dressing materials for wound healing, combining network analysis and natural language processing using large language models. Contributions to this field come from a variety of research areas and journals, so we employed multiple strategies for searching the OpenAlex database to ensure that the most relevant papers were covered, while also focusing on the specific topic of interest. Citation networks were created from the retrieved papers, identifying clusters that represent major topics. Starting with broad searches on 'wound' and 'wound healing' we refined the focus to dressing materials by incorporating expert knowledge into the analysis. This approach also allowed for a comparison with fully automated analyses. The resulting landscape shows significant growth in this area in recent years, with most contributions coming from the Northern Hemisphere, particularly China and the USA. The most commonly used materials include gauze, hydrocolloids, chitosan-based hydrogels, foams, alginates, hydrofibers (e.g., those containing nanomaterials such as silver nanoparticles), composites, biomaterials, and skin substitutes. Research primarily focuses on the antibacterial properties of these materials and their application in treating burn-related wounds, which, along with diabetes, are common causes of chronic wounds.

Hemostatic and antimicrobial properties of chitosan-based wound healing dressings: A review

Uncontrolled bleeding and microbial infections pose significant hurdles in wound healing, and the use of specialized functional dressings is pivotal in overcoming these obstacles. Among the various wound dressings currently under investigation, those based on chitosan and its derivatives have garnered significant attention due to their superior biocompatibility, antimicrobial properties, hemostatic capabilities, and healing promoting ability. In this comprehensive review, we initially delve into the hemostatic capabilities of chitosan, elucidating its interactions with blood cells and plasma proteins. We also dissect the intricate antimicrobial mechanisms of chitosan, which operate through both intracellular and extracellular pathways. The centerpiece of this review is the systematic classification of dressings based on chitosan and its derivatives, across various forms, such as hydrogels, sponges, membranes, fibers, and powders. This is followed by an exhaustive analysis of their hemostatic and antibacterial efficacy in wound healing, providing a robust foundation for further research and the advancement of clinical applications in the field.

Preparation and characterization of thermosensitive phase-transition hydrogel based on decanoic acid-modified chitosan and methyl cellulose for wound healing

Hydrogels with good biocompatibility, suitable physicochemical properties, and effective wound healing promotion are currently recognized as ideal candidates for wound dressings. This study introduced an innovative thermosensitive phase-transition hydrogel (CSDA-MC-HG) for skin wound repair, prepared using decanoic acid-modified chitosan (CSDA) and methyl cellulose (MC). The enhanced hydrophobic interaction with increasing temperature was the primary mechanism behind the thermosensitive phase-transition property of CSDA-MC-HG. Rheological measurement confirmed that CSDA-MC-HG possessed adequate spreadability and adaptability, allowing it to conform well to irregular shaped wounds and be easily applied and replaced. The other characterization findings indicated that CSDA-MC-HG possessed ideal interconnected porous structure, along with superior swelling capacity, water retention ability, and water vapor permeability necessary for an optimal wound dressing. Biocompatibility experiments indicated that CSDA-MC-HG exhibited satisfactory blood compatibility and cell compatibility, supporting the proliferation and migration of L929 cells. Furthermore, the hydrogel's potential as a wound dressing was tested on SD rats with full-thickness skin wounds. The results indicated that CSDA-MC-HG effectively promoted wound healing by enhancing fibroblast proliferation, accelerating the formation of new blood vessels and skin appendages, and facilitating collagen deposition. The findings presented suggested that CSDA-MC-HG held significant potential for application as a wound healing dressing.

Self-Healing Hydrogels: Mechanisms and Biomedical Applications

Hydrogels have emerged as dependable candidates for tissue repair because of their exceptional biocompatibility and tunable mechanical properties. However, conventional hydrogels are vulnerable to damage owing to mechanical stress and environmental factors that compromise their structural integrity and reduce their lifespan. In contrast, self-healing hydrogels with their inherent ability to restore structure and function autonomously offer prolonged efficacy and enhanced appeal. These hydrogels can be engineered into innovative forms including stimulus-responsive, self-degradable, injectable, and drug-loaded variants, thereby enhancing their applicability in wound healing, drug delivery, and tissue engineering. This review summarizes the categories and mechanisms of self-healing hydrogels, along with their biomedical applications, including tissue repair, drug delivery, and biosensing. Tissue repair includes wound healing, bone-related repair, nerve repair, and cardiac repair. Additionally, we explored the challenges that self-healing hydrogels continue to face in tissue repair and presented a forward-looking perspective on their development. Consequently, it is anticipated that self-healing hydrogels will be progressively designed and developed for applications that extend beyond tissue repair to a broader range of biomedical applications.

Study on the structural characterization of Premna microphylla Turcz polysaccharides and their improvement effect on the properties of chitosan composite gel

Bioactive polysaccharide composite gels provide strategy for improving the defects of chitosan (CS) gel. The aim of this study was to characterize the structure of Premna microphylla Turcz polysaccharide (PMTP) and investigate the improvement of different PMTP concentrations (4, 6, 8, 10, and 12 wt%) on the PMTP/CS composite gels' properties. PMTP is an acidic heteropolysaccharide with →4)-α-D-GalpA-(1→ and →4)-α-D-Galpa-6-Ome-(1→ as the backbone structure. And PMTP transformed the gel's framework from the lamellar structure of CS gel to 3D porous network constructed by connected nanofibers. This resulted in the increase of surface area from 11.28 to 89.72 m2/g and reduction of pore size from 5.76 to 0.52 μm. Moreover, the mechanical properties of PMTP/CS composite gel was significantly improved 17.9 times higher than that of CS gel. Accordingly, the water holding, swelling, rheology and thermal stability of PMTP/CS gel were further improved. Study on gelation mechanism proved that the formation of composite gel's 3D network was mainly dominated by electrostatic interaction. Finally, Caco-2 cell assay in vitro confirmed the excellent cytocompatibility of PMTP/CS gel. In conclusion, this work provides a scientific reference for the design of bioactive polysaccharide composite gel for food engineering field.

Selenium-Albumin Nanoaccelerator Hydrogel Promotes Wound Healing by Antibacterial, Anti-Inflammatory and Antioxidant along with Inhibits Scar Formation via Downregulating CD36

Wounds repairing after skin damage or diabetes remain a vast medical challenge, which often faces infection, inflammation, oxidative stress, and skin scarring. Herein, a multifunctional selenium-albumin nanoaccelerator hydrogel (H-Se NPs-Gel) is constructed based on the self-assembly of human serum albumin (HSA) with selenium nanoparticles (Se NPs) using carbomer as the carrier, it has remarkable antibacterial, anti-inflammatory, antioxidant and inhibits scarring properties than Se NPs for wound healing. Compared with Se NPs, H-Se NPs exhibit smaller particle sizes, exceptional stability, better antibacterial activity against common bacteria and MRSA, and superior antioxidant and anti-inflammatory capabilities in vitro without remarkable toxicity on skin cells. Importantly, it exhibits superior efficacy to Se NPs-Gel in accelerating the healing of full-thickness skin defects and diabetic wounds in mice. Interestingly, in a hypertrophic scar (HTS) model, H-Se NPs-Gel is more effective than Se NPs-Gel in inhibiting collagen formation to suppress scarring, which is mediated by the inhibition of CD36. The antagonistic effect of H-Se NPs on CD36 is also proved with the CD36 overexpression model. Furthermore, H-Se NPs-Gel demonstrates excellent safety in mice without systemic toxicity. H-Se NPs-Gel is an effective and safe therapy strategy for promoting wound healing and reducing scar formation in clinic.

Electrical hydrogel: electrophysiological-based strategy for wound healing

Wound healing remains a significant challenge in clinical practice, driving ongoing exploration of innovative therapeutic approaches. In recent years, electrophysiological-based wound healing strategies have gained considerable attention. Specifically, electrical hydrogels combine the synergistic effects of electrical stimulation and hydrogel properties, offering a range of functional benefits for wound healing, including antibacterial activity, real-time wound monitoring, controlled drug release, and electrical treatment. Despite significant progress made in electrical hydrogel research for wound healing, there is a lack of comprehensive, systematic reviews summarizing this field. In this review, we survey the latest advancements in electrical hydrogel technology. After analyzing the mechanisms of electrical stimulation in promoting wound healing, we establish a novel classification framework for electrical hydrogels based on their operational principles. The review further provides an in-depth evaluation of the therapeutic efficacy of these hydrogels in various types of wounds. Finally, we propose future directions and challenges for the development of electrical hydrogels for wound healing.

Self-healing adhesive oxidized guar gum hydrogel loaded with mesenchymal stem cell exosomes for corneal wound healing

Hydrogels have shown great potential and value in wound healing. In this study, we construct a mesenchymal stem cell exosomes (MSC-Exos) laden natural biopolymer-based hydrogel with transparent, self-healing, injectable, and tissue adhesive properties to promote corneal regeneration. This hydrogel is synthesized by combining aldehyde-modified oxidized guar gum (OGG) and carboxymethyl chitosan (CMCS) through the dynamic, reversible Schiff base bonds, which endow it with outstanding shear-thinning and self-healing properties, facilitating easy injection through a needle. The physicochemical properties, such as porosity, mechanical strength, and light transmittance, could be precisely tunable by adjusting OGG concentrations. The resultant hydrogel achieves robust tissue adhesion at physiological temperatures due to Schiff base interactions. Besides, the Exos can be uptaken by the corneal epithelial cells and subsequently promote the migration of the cells. We have proven that the MSC-Exos-loaded hydrogel adheres firmly to the defected cornea and significantly improves wound repair by enhancing collagen deposition and reducing inflammation in a rabbit cornea defect model. These results indicated that this multifunctional hydrogel holds immense scientific promise and offers a wide range of clinical applications.

Advancements in Wearable and Implantable BioMEMS Devices: Transforming Healthcare Through Technology

Wearable and implantable BioMEMSs (biomedical microelectromechanical systems) have transformed modern healthcare by enabling continuous, personalized, and minimally invasive monitoring, diagnostics, and therapy. Wearable BioMEMSs have advanced rapidly, encompassing a diverse range of biosensors, bioelectronic systems, drug delivery platforms, and motion tracking technologies. These devices enable non-invasive, real-time monitoring of biochemical, electrophysiological, and biomechanical signals, offering personalized and proactive healthcare solutions. In parallel, implantable BioMEMS have significantly enhanced long-term diagnostics, targeted drug delivery, and neurostimulation. From continuous glucose and intraocular pressure monitoring to programmable drug delivery and bioelectric implants for neuromodulation, these devices are improving precision treatment by continuous monitoring and localized therapy. This review explores the materials and technologies driving advancements in wearable and implantable BioMEMSs, focusing on their impact on chronic disease management, cardiology, respiratory care, and glaucoma treatment. We also highlight their integration with artificial intelligence (AI) and the Internet of Things (IoT), paving the way for smarter, data-driven healthcare solutions. Despite their potential, BioMEMSs face challenges such as regulatory complexities, global standardization, and societal determinants. Looking ahead, we explore emerging directions like multifunctional systems, biodegradable power sources, and next-generation point-of-care diagnostics. Collectively, these advancements position BioMEMS as pivotal enablers of future patient-centric healthcare systems.

Advancements in insulin delivery: the potential of natural polymers for improved diabetes management

Diabetes is a growing global health issue, with millions of people affected by the condition. While insulin therapy is vital for managing both Type 1 and Type 2 diabetes, traditional methods such as subcutaneous injections have notable drawbacks, including pain, discomfort, and difficulty in maintaining stable blood sugar levels. To improve insulin delivery, research is increasingly focused on the use of natural polymers-substances derived from plants, animals, and microorganisms. These polymers, including materials like alginate, chitosan, and hyaluronic acid, have promising properties such as biocompatibility, biodegradability, and the ability to provide controlled, sustained insulin release. By encapsulating insulin in polymers, it is protected from degradation and released in a manner that more closely mirrors the body's natural insulin production. Furthermore, the development of non-invasive delivery methods, such as oral and transdermal systems, is gaining momentum, offering the potential for more patient-friendly treatment options. This review discusses the role of natural polymers in insulin delivery, examining their mechanisms, types, and current research efforts. It also addresses the challenges that remain in advancing these technologies into practical clinical use, aiming to provide more efficient, comfortable, and effective solutions for diabetes management.

Tannic acid-etched PAN/PVP nanofibers loaded with Cu-MOFs enhance antibacterial efficacy and accelerate wound healing

Wound infection represents a prevalent and pressing clinical challenge, resulting in delayed wound healing and severe complications. In this study, a novel wound dressing was fabricated through a combination of electrospinning and acid etching techniques. First, nanofibers were fabricated by blending electrospun polyacrylonitrile/Polyvinylpyrrolidone (PAN/PVP) polymers with copper-based metal organic frameworks (Cu-MOFs). Subsequently, tannic acid was employed to etch the surface sites of Cu-MOFs on the fibers. The obtained nanofibers exhibited a typical porous structure, superior water absorption and gas permeability, with the average water vapor transmission rate was 2170.6 gm-2day-1. Additionally, the release behavior of copper ions can be modulated by altering the mass ratio of PVP to PAN, the amount of Cu-MOFs and the use of tannic acid. In vitro antibacterial assays revealed that the antibacterial efficacy of nanofibers increased with the addition of Cu-MOFs, after 48 hours of treatment, the inhibition rates of the nanofibers against E. coli and S. aureus reached over 79.5 % and 90 %, respectively. In vivo experiments demonstrated that these nanofibers alleviated wound inflammation and promoted collagen and angiogenesis, exhibition superior anti-inflammatory and wound-healing effects. The biosafety tests indicated that the nanofibers loaded with 1 % and 3 % Cu-MOFs exhibited good biocompatibility, while the nanofibers loaded with 5 % Cu-MOFs showed slight cytotoxicity. This study provides a novel strategy for the design and fabrication of advanced wound dressings in biomedical applications.

Quaternized chitosan-based injectable self-healing hydrogel for improving wound management in aging populations

The clinical management and treatment of skin wounds in the elderly present significant challenges due to changes in skin structure and function. This study introduces a novel injectable self-healing hydrogel composed of quaternized chitosan and carboxymethyl chitosan (HACC/CMCS, HC), designed through electrostatic interactions. Its excellent injectability and self-healing properties enhance the application of hydrogel dressings and prolong their functional lifespan. Moreover, the adhesion and flexibility of HC hydrogel contribute to their stability in highly dynamic regions, thereby preventing detachment and enhancing their hemostatic function. The material exhibits excellent biocompatibility and possesses antibacterial properties that protect wounds from external microbial damage, thereby reducing the risk of infection while maintaining a moist environment that facilitates healing. Importantly, the in vivo test have demonstrated that the HC hydrogel significantly enhances collagen deposition, reduces senescent cell accumulation, and accelerates wound closure. Therefore, this study offers a safe, effective, and cost-efficient solution for managing wounds in the aging population.

Polymer Applied in Hydrogel Wound Dressing for Wound Healing: Modification/Functionalization Method and Design Strategies

Hydrogel wound dressings have emerged as a promising solution for wound healing due to their excellent mechanical and biochemical properties. Over recent years, there has been significant progress in expanding the variety of raw materials used for hydrogel formulation along with the development of advanced modification techniques and design approaches that enhance their performance. However, a comprehensive review encompassing diverse polymer modification strategies and design innovations for hydrogel dressings is still lacking in the literature. This review summarizes the use of natural polymers (e.g., chitosan, gelatin, sodium alginate, hyaluronic acid, and dextran) and synthetic polymers (e.g., poly(vinyl alcohol), polyethylene glycol, Pluronic F-127, poly(N-isopropylacrylamide), polyacrylamide, and polypeptides) in hydrogel wound dressings. We further explore the advantages and limitations of these polymers and discuss various modification strategies, including cationic modification, oxidative modification, double-bond modification, catechol modification, etc. The review also addresses design principles and synthesis methods, aligning polymer modifications with specific requirements in wound healing. Finally, we discuss future challenges and opportunities in the development of advanced hydrogel-based wound dressings.

Smart self-healing hydrogel wound dressings for diabetic wound treatment

Diabetic wounds are difficult to treat clinically because they heal poorly, often leading to severe complications such as infections and amputations. Hydrogels with smart self-healing properties show great promise for treating diabetic wounds. These hydrogels are capable of continuously and dynamically responding to changes in the wound environment, feature improved mechanical qualities and the capacity to self-heal damage. We explore the latest developments in smart self-healing hydrogels for diabetic wound healing in this review. First, we systematically summarize the obstacles in treating diabetic wounds. We then highlighted the significance of smart self-healing hydrogels, explaining their stimulus-responsive mechanisms and self-healing design approaches, along with their applications in addressing these challenges. Finally, we discussed the unresolved obstacles and potential avenues for future research. We anticipate that this review will facilitate the continued refinement of smart self-healing hydrogels for diabetic wound dressings, aiming for broader clinical adoption.

Polysaccharides, proteins and DNA based stimulus responsive hydrogels promoting wound healing and repair: A review

The healing of various wounds remains a serious challenge in the medical field, hydrogel has high hydrophilicity and biocompatibility due to its unique network structure, which shows a strong advantage in the field of wound healing. Stimulus responsive hydrogels are particularly effective，which can control the material properties according to the external stimulus source, and provide more targeted treatment for different wounds. Here, we review physiological mechanisms of wound healing and the relationship between polysaccharides, proteins and DNA based stimulus responsive hydrogels and wound healing, materials commonly used of polysaccharides, proteins and DNA based stimulus responsive hydrogels, mechanisms of stimulus responsive hydrogels formation and network structure types, common properties of polysaccharides, proteins and DNA based stimulus responsive hydrogels for promoting wound healing and discuss their applications in medicine. Finally, the limitations and application prospects of polysaccharides, proteins and DNA based stimulus responsive hydrogels were discussed and evaluated. The review focuses on the biomedical use of polysaccharides, proteins and DNA based stimulus responsive hydrogels in wound healing and repair, and provides insights for the development of clinical related materials.

Light-triggered release of nitric oxide from chitosan-based cationic hydrogels for promoting infected wounds healing

Infected wounds are highly susceptible to bacterial contamination, which not only delays the healing process but also leads to a range of complications. NO is one of the most widely used gas molecules in wound treatment strategies due to its potent antibacterial and healing-promoting properties. However, excessive NO in infected wounds can damage cellular components and exacerbate inflammation. Therefore, precise control of NO dosage and targeted delivery to the wound site are crucial for effective treatment. Herein, a cationic hydrogel was constructed using modified guar gum and polyvinyl alcohol to enhance antibacterial effects, with guanidine-modified chitosan (Met-CS) and the photosensitizer sodium copper chlorophyllin (SCC) incorporated to create a light-triggered NO release system. Both in vitro and in vivo experiments confirmed that the proposed hydrogel exhibits excellent antibacterial performance, anti-inflammatory effects, and wound healing capabilities, demonstrating its potential for precise therapeutic applications.

Bioactive hemostatic materials: a new strategy for promoting wound healing and tissue regeneration

Wound healing remains a critical global healthcare challenge, with an annual treatment cost exceeding $50 billion worldwide. Over the past decade, significant advances in wound care have focused on developing sophisticated biomaterials that promote tissue regeneration and prevent complications. Despite these developments, there remains a crucial need for multifunctional wound healing materials that can effectively address the complex, multiphase nature of wound repair while being cost effective and easily applicable in various clinical settings. This review systematically analyzes the latest developments in wound healing materials, examining their chemical composition, structural design, and therapeutic mechanisms. We comprehensively evaluate various bioactive components, including natural polymers, synthetic matrices, and hybrid composites, along with their different forms, such as hydrogels, powders, and smart dressings. Special attention is given to emerging strategies in material design that integrate multiple therapeutic functions, including sustained drug delivery, infection prevention, and tissue regeneration promotion. The insights provided in this review illuminate the path toward next-generation wound healing materials, highlighting opportunities for developing more effective therapeutic solutions that can significantly improve patient outcomes and reduce healthcare burden.

Dual-network hydrogel loaded with antler stem cells conditioned medium and EGCG promotes diabetic wound healing through antibacterial, antioxidant, anti-inflammatory, and angiogenesis

Diabetic wound healing is characterized by persistent inflammation, reactive oxygen species overproduction, bacterial infection, and compromised angiogenesis. In recent years, Antler Stem Cells (ASCs) have attracted attention because of their potential role in promoting wound healing by promoting cell proliferation and angiogenesis via paracrine effects. In addition, epigallocatechin gallate (EGCG), the main component of green tea, exhibits antibacterial, anti-inflammatory, and antioxidant properties. In this study, we designed and fabricated a gelatin (G)/sodium alginate (SA)-based (SA/G) dual-network hydrogel loaded with ASC-derived conditioned medium (ASC-CM) and EGCG (CEGA) that exhibited excellent swelling capacity, sustained release, and mechanical properties. Both in vitro and in vivo experiments demonstrated that CEGA hydrogels were capable of enhancing cell proliferation, promoting angiogenesis, exhibiting antibacterial properties, mitigating inflammation, and regulating macrophage polarization. These results substantiate their potential application as novel dressings for healing diabetic skin wounds.

Dual ROS/Glucose-Responsive Quercetin-Loaded Supramolecular Hydrogel for Diabetic Wound Healing

Diabetic wound healing remains a significant challenge due to complex pathological mechanisms, including prolonged inflammation, excessive reactive oxygen species (ROS) accumulation, angiogenesis dysfunction, and increased susceptibility to bacterial infection. In this study, we developed a dual ROS/glucose-responsive quercetin-loaded supramolecular hydrogel (GPQ hydrogel) for treating diabetic wounds. The hydrogel was fabricated by incorporating quercetin (QUE) into a guanosine-phenylboronic acid (GP) hydrogel network through dynamic borate ester bonds. Structural characterization revealed the formation of a typical G-quadruplex structure in the GPQ hydrogel. The dual responsiveness to ROS and glucose enabled the controlled release of QUE, effectively addressing the abnormal wound microenvironment in diabetes. In vitro studies demonstrated the excellent antibacterial, antioxidant, anti-inflammatory, and pro-angiogenic properties of the GPQ hydrogel. Furthermore, the in vivo diabetic wound healing study using a full-thickness wound model in streptozotocin-induced diabetic rats showed that the GPQ hydrogel significantly accelerated wound closure, enhanced re-epithelialization and collagen deposition, and promoted angiogenesis compared to the control and GP hydrogel groups. Immunofluorescence analysis confirmed the superior antioxidant and pro-angiogenic effects of the GPQ hydrogel in the wound microenvironment. This study presents a promising multifunctional biomaterial for effectively managing diabetic wounds.

Double cross-linked cellulose hydrogel-supported Fe species for efficient wound healing

Traditional dressings often lack adequate skin structure support, which can lead to secondary damage, poor hemostasis, and an increased risk of inflammation due to wound adhesion. In this work, cellulose hydrogels were prepared by physical/chemical double cross-linking via a 'sol-gel' strategy and further loaded with Fe to obtain a three-dimensional (3D) porous cellulose/Fe composite hydrogel (cellulose/Fe gel). The obtained cellulose/Fe gel featured a 3D porous nanofiber structure, excellent water absorption/moisture retention performance, and good mechanical stability. Moreover, it could effectively remove reactive oxygen species (ROS) and inhibit cellular oxidative stress, demonstrating potential anti-inflammatory effects. When applied to wound repair in rats, cellulose/Fe gel, with excellent cell compatibility, effectively stimulated the formation of new blood vessels and significantly reduced the level of inflammatory factors, promoting wound healing. This work provides a new approach for cellulose-based hydrogel wound dressings.

Exos-Loaded Gox-Modified Smart-Response Self-Healing Hydrogel Improves the Microenvironment and Promotes Wound Healing in Diabetic Wounds

Wound management has always been a challenge in the clinical treatment of diabetes. In this study, glucose oxidase (GOx) is grafted onto natural pullulan polysaccharides, and oxidization is carried out to form a self-healing hydrogel using carboxymethyl chitosan by means of reversible Schiff base covalent bonding. The smart-response drug release properties of this natural self-healing hydrogel are demonstrated in diabetic wounds by taking advantage of two key factors, namely the pH-responsive nature of Schiff base bonding and the fact that GOx reduces the pH in diabetic wounds. To further enhance the biological functions of the hydrogel dressing, exosomes (Exos) are introduced into the hydrogel system. The GOx present in the hydrogel system improves the high-glucose microenvironment of diabetic wounds, releasing H2O2 to impart antimicrobial effects, and ensuring that the hydrogel realizes a smart-response function. The carboxymethyl chitosan component used to construct the hydrogel plays an effective antibacterial role. Moreover, the Exos loaded into the hydrogel effectively promotes neovascularization of the wound. The Exos also regulates macrophage polarization and reduces the levels of persistent inflammation in diabetic wounds. These results suggest that this smart responsive, multifunctional, and self-healing hydrogel dressing is ideal for the management of diabetic wounds.

Tough, highly conductive and frost-resistant chitosan based hydrogel for flexible sensor

Conductive hydrogels with exceptional mechanical properties have received extensive attention in flexible strain sensors. However, there is still a huge challenge in the preparation of hydrogels with high toughness, conductivity and frost resistance performance. In this study, the prepared PA-PAAM-CS (PPAC) composite hydrogels were obtained by incorporating phytic acid (PA) and chitosan (CS) into poly(acrylamide-co-stearyl methacrylate) (PAAM) polymer network. The as-prepared PPAC composite hydrogel has exhibited good mechanical properties, good electrical conductivity, frost resistance and good strain sensitivity. The flexible strain sensor assembled by the fabricated PPAC hydrogel can be used to detect human motion, including small and huge human motion, showing good sensitivity and stability in a wide temperature range. Meanwhile, the hydrogels based pressure sensors as writing board have exhibited good sensitivity to tiny changes in writing various letters. Therefore, the prepared hydrogel will have broad application prospects in wearable devices, electronic skin and multifunctional sensor components.

An antimicrobial and adhesive conductive chitosan quaternary ammonium salt hydrogel dressing for combined electrical stimulation and photothermal treatment to promote wound healing

The aim of this study is to investigate the effect of the adhesive, conductive hydrogel on wound healing when used as a therapeutic dressing. Herein, a dressing of PVA/QCS/TP@Fe3+ (PQTF) was designed and prepared integrating polyvinyl alcohol (PVA), chitosan quaternary ammonium salt (QCS), tea polyphenol (TP), and ferric ions (Fe3+) by a simple one-pot and freeze-thaw method. In view of the comprehensive properties of PQTF600 hydrogel, including adhesion, electrical conductivity, and swelling performance, PQTF600 was selected for subsequent in vitro and in vivo healing promotion studies. PQTF600 had good adhesion and conductive ability, which was suitable for human motion monitoring and wound treatment. Notably, the PQTF600 showed and controllable human safety temperature thresholds (~44.8 °C) under near-infrared light (NIR). Meanwhile, PQTF600 achieved nearly 100 % antibacterial activity against Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and Pseudomonas putida (P. putida), methicillin-resistant Staphylococcus aureus (MRSA). In addition, the PQTF600 hydrogel dressing was demonstrated to achieve 99.59 ± 4.11 % would healing rate in a mouse trauma model under the dual stimulation of NIR (808 nm) and electricity (1.5 V direct current). The versatile PQTF600 hydrogel is a promising dressing for enhancing wound closure integrating with electrical stimulation (ES) and photothermal therapy.

Cellulose-mediated mechanical property tuning in small intestinal submucosal matrix to enhance stem cell osteogenic differentiation

Natural extracellular matrices (ECM) provide a more accurate simulation of the cellular growth environment, making them excellent substrate materials for in vitro cell culture. The porcine small intestinal submucosa (SIS) is one of the most widely used natural ECM that display superior bioactivity. However, decellularization operations often result in fiber breakage and failure to recover mechanical strength in the SIS. In the current study, 2,3-dialdehyde cellulose (DAC) was synthesized and cross-linked with SIS gel to form hydrogels. The introduction of DAC into the SIS matrix resulted in a tunable increase in stiffness, which was instrumental in promoting stem cell adhesion and spreading, crucial factors for osteogenic differentiation. The cytotoxicity assessment confirmed the biocompatibility of the SIS-DAC hydrogels indicating their suitability for prolonged cell culture. Moreover, the degradation rate of the hydrogel could be effectively controlled by adjusting the DAC content, addressing the rapid degradation issue associated with SIS gels. This work confirmed the feasibility of using cellulose derivatives to modulate the mechanical properties of matrix gels and influence cell differentiation which offers a valuable experimental foundation for the development of advanced matrix gels tailored for cell culture and regenerative medicine applications.

Self-Healing Hydrogels with Intrinsic Antioxidant and Antibacterial Properties Based on Oxidized Hydroxybutanoyl Glycan and Quaternized Carboxymethyl Chitosan for pH-Responsive Drug Delivery

In this study, self-healing hydrogels were created using oxidized hydroxybutanoyl glycan (OHbG) and quaternized carboxymethyl chitosan (QCMCS), displaying antioxidant and antibacterial properties for pH-responsive drug delivery. The structures of the modified polysaccharides were confirmed through 1H NMR analysis. Double crosslinking in the hydrogel occurred via imine bonds (between the aldehyde group of OHbG and the amine group of QCMCS) and ionic interactions (between the carboxyl group of OHbG and the quaternized group of QCMCS). The hydrogel exhibited self-healing properties and improved thermal stability with an increase in OHbG concentration. The OHbG/QCMCS hydrogel demonstrated high compressive strength, significant swelling, and large pore size. Drug release profiles varied between pH 2.0 (96.57%) and pH 7.4 (63.22%). Additionally, the hydrogel displayed antioxidant and antibacterial effects without compromising the polysaccharides' inherent characteristics. No cytotoxicity was observed in any hydrogel samples. These findings indicate that the OHbG/QCMCS hydrogel is a biocompatible and stimuli-responsive drug carrier, with potential for various pharmaceutical, biomedical, and biotechnological applications.

Enhancing mechanical properties of chitosan/PVA electrospun nanofibers: a comprehensive review

This review examines strategies to enhance the mechanical properties of chitosan/polyvinyl alcohol (PVA) electrospun nanofibers, recognized for their biomedical and industrial applications. It begins by outlining the fundamental properties of chitosan and PVA, highlighting their compatibility and mechanical characteristics. The electrospinning process is discussed, focusing on how various parameters and post-treatment methods influence fiber formation and performance. Key strategies for improvement are analyzed, including material modifications through blending and structural modifications like fiber orientation and multilayer constructions, and surface modifications such as coating and functionalization. The review also covers advanced characterization methods to evaluate mechanical properties and provides a comparative analysis of different enhancement approaches. Applications in biomedical and industrial contexts are explored, showcasing the versatility and innovation potential of these nanofibers. Finally, current challenges are addressed, and future research directions are proposed to overcome these obstacles and further enhance the mechanical properties of chitosan/PVA electrospun nanofibers, guiding their development for practical applications.

Construction of pH-responsive hydrogel coatings on titanium surfaces for antibacterial and osteogenic properties

Infection is one of the leading causes of failure in titanium-based implant materials during clinical surgeries, often resulting in delayed or non-union of bone healing. Furthermore, the overuse of antibiotics can lead to bacterial resistance. Therefore, developing a novel titanium-based implant material with both antimicrobial and osteogenic properties is of great significance. In this study, chitosan (CS), polydopamine (PDA), and antimicrobial peptides (AMPs) HHC36 were applied to modify the surface of titanium, resulting in the successful preparation of the composite material Ti-PDA-CS/PDA@HHC36 (abbreviated as T-P-C/P@H). CS promotes osteogenesis and cell adhesion, providing an ideal microenvironment for bone repair. PDA enhances the material's biocompatibility and corrosion resistance, offering cell adhesion sites, while both components exhibit pH-responsive characteristics. The HHC36 effectively prevents infection, protecting the bone repair material from bacterial damage. Overall, the synergistic effects of these components in T-P-C/P@H not only confer excellent antimicrobial and osteogenic properties but also improve biocompatibility, offering a new strategy for applying titanium-based implants in clinical settings.

Advancements in Wound Dressing Materials: Highlighting Recent Progress in Hydrogels, Foams, and Antimicrobial Dressings

Recent advancements in wound dressing materials have significantly improved acute and chronic wound management by addressing challenges such as infection control, moisture balance, and enhanced healing. Important progress has been made, especially with hydrogels, foams, and antimicrobial materials for creating optimized dressings. Hydrogels are known for maintaining optimal moisture levels, while foam dressings are excellent exudate absorbents. Meanwhile, antimicrobial dressing incorporates various antimicrobial agents to reduce infection risks. These dressing options reduce wound healing time while focusing on customized patient needs. Therefore, this review highlights the newest research materials and prototypes for wound healing applications, emphasizing their particular benefits and clinical importance. Innovations such as stimuli-responsive hydrogels and hybrid bioengineered composites are discussed in relation to their enhanced properties, including responsiveness to pH, temperature, glucose, or enzymes and drug delivery precision. Moreover, ongoing clinical trials have been included, demonstrating the potential of emerging solutions to be soon translated from the laboratory to clinical settings. By discussing interdisciplinary approaches that integrate advanced materials, nanotechnology, and biological insights, this work provides a contemporary framework for patient-centric, efficient wound care strategies.

Recent advances in modifications, biotechnology, and biomedical applications of chitosan-based materials: A review

Chitosan, a natural polysaccharide with recognized biocompatibility, non-toxicity, and cost-effectiveness, is primarily sourced from crustacean exoskeletons. Its inherent limitations such as poor water solubility, low thermal stability, and inadequate mechanical strength have hindered its widespread application. However, through modifications, chitosan can exhibit enhanced properties such as water solubility, antibacterial and antioxidant activities, adsorption capacity, and film-forming ability, opening up avenues for diverse applications. Despite these advancements, realizing the full potential of modified chitosan remains a challenge across various fields. The purpose of this review article is to conduct a comprehensive evaluation of the chemical modification techniques of chitosan and their applications in biotechnology and biomedical fields. It aims to overcome the inherent limitations of chitosan, such as low water solubility, poor thermal stability, and inadequate mechanical strength, thereby expanding its application potential across various domains. This review is structured into two main sections. The first part delves into the latest chemical modification techniques for chitosan derivatives, encompassing quaternization, Schiff base formation, acylation, carboxylation, and alkylation reactions. The second part provides an overview of the applications of chitosan and its derivatives in biotechnology and biomedicine, spanning areas such as wastewater treatment, the textile and food industries, agriculture, antibacterial and antiviral activities, drug delivery systems, wound dressings, dental materials, and tissue engineering. Additionally, the review discusses the challenges associated with these modifications and offers insights into potential future developments in chitosan-based materials. This review is anticipated to offer theoretical insights and practical guidance to scientists engaged in biotechnology and biomedical research.

Catechol-grafted chitosan-based antioxidant hydrogel with rapid self-healing property for wound healing

Chronic wounds, particularly those with non-healing ulcers, show high levels of oxidant stress, such as excessive reactive oxygen species (ROS), which delays the healing process. Bacterial infections in wounds increase the need for antibiotics, which brings up serious concerns regarding antibiotic resistance. The innovative antibiotic-free strategies to endow the hydrogels with antibacterial and antioxidant features including the grafting of ROS-scavenging moieties onto the hydrogel structure are in high demand for wound management. Herein, an antibacterial and antioxidant hydrogel with rapid self-healing performance was fabricated via the dynamic borate ester cross-linkages between catechol-grafted chitosan (CS-CA) and polyvinyl alcohol in the presence of borax with the incorporation of ellagic acid (EA). Benefiting from the catechol groups from EA and CS-CA, the resulting hydrogel exhibited desirable adhesive property, excellent antioxidant and intensified antibacterial dual functions. Furthermore, the hydrogel demonstrated remarkable biocompatibility and pH-responsive behavior for the controlled release of EA, attributed to the reversible characteristics of borate ester linkages. Notably, these multifunctional hydrogels exhibited substantial regenerative capabilities in wound healing, as evidenced by in vivo assessments conducted on a full-thickness skin defect model, highlighting their considerable potential as wound dressings for effective wound management.

Recent Advancements in Chitosan-Based Biomaterials for Wound Healing

Chitosan is a positively charged natural polymer with several properties conducive to wound-healing applications, such as biodegradability, structural integrity, hydrophilicity, adhesiveness to tissue, and bacteriostatic potential. Along with other mechanical properties, some of the properties discussed in this review are antibacterial properties, mucoadhesive properties, biocompatibility, high fluid absorption capacity, and anti-inflammatory response. Chitosan forms stable complexes with oppositely charged polymers, arising from electrostatic interactions between (+) amino groups of chitosan and (-) groups of other polymers. These polyelectrolyte complexes (PECs) can be manufactured using various materials and methods, which brings a diversity of formulations and properties that can be optimized for specific wound healing as well as other applications. For example, chitosan-based PEC can be made into dressings/films, hydrogels, and membranes. There are various pros and cons associated with manufacturing the dressings; for instance, a layer-by-layer casting technique can optimize the nanoparticle release and affect the mechanical strength due to the formation of a heterostructure. Furthermore, chitosan's molecular weight and degree of deacetylation, as well as the nature of the negatively charged biomaterial with which it is cross-linked, are major factors that govern the mechanical properties and biodegradation kinetics of the PEC dressing. The use of chitosan in wound care products is forecasted to drive the growth of the global chitosan market, which is expected to increase by approximately 14.3% within the next decade. This growth is driven by products such as chitoderm-containing ointments, which provide scaffolding for skin cell regeneration. Despite significant advancements, there remains a critical gap in translating chitosan-based biomaterials from research to clinical applications.

Injectable Chitosan Hydrogel Particles as Nasal Packing Materials After Endoscopic Sinus Surgery for Treatment of Chronic Sinusitis

After endoscopic sinus surgery (ESS), nasal packing is often used to stop bleeding and promote wound healing. Because maintaining a moist environment is important to enhance wound healing, hydrogel-based wound dressings are effective to promote wound healing. Chitosan is used in the medical field because of its high hemostatic and wound healing properties. We developed a pH-neutral and non-toxic chitosan hydrogel, which was difficult to achieve using conventional methods. In this study, we show in animal experiments that the chitosan hydrogel (hydrogel particles) had higher wound healing properties than a commercially available solid wound dressing (dry state) composed of the same polymer. Additionally, we applied the injectable chitosan hydrogel particles as nasal packing materials to patients with bilateral chronic sinusitis undergoing ESS in a pilot clinical study. Concerning symptom scores, though the results narrowly missed statistical differences (p < 0.05), the average scores of our chitosan hydrogel were superior to those of a commercially available wound dressing (especially p = 0.09 for nasal bleeding). These findings suggest that the injectable chitosan hydrogel could be a viable option as a packing material following ESS.