A functional chitosan-based hydrogel as a wound dressing and drug delivery system in the treatment of wound healing

The impact of copper nanoparticles surfactant on the structural and biological properties of chitosan/sodium alginate wound dressings

Multifunctional wound dressings based on hydrogels are an efficacious and practicable strategy in therapeutic processes and accelerated chronic wound healing. Here, copper (Cu) nanoparticles were added to chitosan/sodium alginate (CS/SA) hydrogels to improve the antibacterial properties of the prepared wound dressings. Due to the super-hydrophobicity of Cu nanoparticles, polyethylene glycol (PEG) was used as a surfactant, and then added to the CS/SA-based hydrogels. The CS/SA/Cu hydrogels were synthesized with 0, 2, 3.5, and 5 wt% Cu nanoparticles. The structural and morphological properties in presence of PEG were evaluated using Fourier-transform infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC), and field emission scanning electron microscopy (FESEM). The biodegradation and swelling properties of the hydrogels were investigated in phosphate buffer saline (PBS) at 37 °C for up to 30 days. Cell viability and adhesion, as well as antibacterial behavior, were investigated via MTT assay, FESEM, and disk diffusion method, respectively. The obtained results showed that PEG provided new intra- and intermolecular bonds that affected significantly the hydrogels' degradation and swelling ratio, which increased up to ~1200 %. Cell viability reached ~110 % and all samples showed remarkable antibacterial behavior when CS/SA/Cu containing 2 wt% was introduced. This study provided new insights regarding the use of PEG as a surfactant for Cu nanoparticles in CS/SA hydrogel wound dressing, ultimately affecting the chemical bonding and various properties of the prepared hydrogels.

Green synthesis of chitosan gum acacia based biodegradable polymeric nanoparticles to enhance curcumin's antioxidant property: an in vivo zebrafish (Danio rerio) study

Green-synthesis of biodegradable polymeric curcumin-nanoparticles using affordable biodegradable polymers to enhance curcumin's solubility and anti-oxidative potential. The curcumin-nanoparticle was prepared based on the ionic-interaction method without using any chemical surfactants, and the particle-size, zeta-potential, surface-morphology, entrapmentefficiency, and in-vitro drug release study were used to optimise the formulation. The antioxidant activity was investigated using H2DCFDA staining in the zebrafish (Danio rerio) model. The mean-diameter of blank nanoparticles was 178.2 nm (±4.69), and that of curcuminnanoparticles was about 227.7 nm (±10.4), with a PDI value of 0.312 (±0.023) and 0.360 (±0.02). The encapsulation-efficacy was found to be 34% (±1.8), with significantly reduced oxidative-stress and toxicity (∼5 times) in the zebrafish model compared to standard curcumin. The results suggested that the current way of encapsulating curcumin using affordable, biodegradable, natural polymers could be a better approach to enhancing curcumin's water solubility and bioactivity, which could further be translated into potential therapeutics.

PLA blended gelatine-based nanofibrous mats with enhanced hydrophobicity for soft tissue regeneration

Wound healing requires a substantial amount of moisture for faster recovery. Completely hydrophobic or hydrophilic biomaterials are not suitable to be applied for cell growth in wounded areas. The study aimed to prepare a nanofibrous scaffold from the blend of a solution of hydrophobic PLA and a solution of hydrophilic gelatine. The stability of the blend was achieved using a surfactant and an electrospun nanofibrous scaffold was made out of the solution. The optimum composition of gelatine and PLA to make a scaffold of uniform fibre diameter was achieved with the help of conductivity, viscosity and FESEM analysis. The optimum scaffold was characterised by TGA, DSC and XRD analysis. The water contact angle of the optimum sample was observed at 27°. The blended scaffold was found non-toxic to cells and showed a 30% faster healing of wounds in the rat model test compared to the healing rate of the PLA scaffold or the gelatine scaffold alone. The histological assay also supported the blend scaffold as an encouraging material for tissue regeneration.

A novel chitosan-PEG hydrogel embedded with in situ silver nanoparticles of Clerodendrum glandulosum Lindl. extract: evaluation of its in vivo diabetic wound healing properties using an image-guided machine learning model

The pathophysiology of chronic wounds related to diabetes mellitus is a result of a series of complications induced by hyperglycemia. The symptoms include impaired growth factor production, decreased keratinocyte proliferation and migration, reduced angiogenesis and cytokine synthesis, lowered matrix metalloproteinase (MMP) production, neuropathy, reduced nitric oxide synthase production, decreased fibroblast synthesis and migration, and impaired inflammatory cell functions. This multifaceted mechanism of diabetic wounds needs a suitable novel topical formulation that can deliver the active constituent by a controlled means, target the various stages of wound healing, absorb the wound exudates, and prevent secondary infections. To meet the above requirements, the Clerodendrum glandulosum (CG) extract reduced silver nanoparticle (AgNP) impregnated chitosan-polyethylene glycol (PEG) hydrogel was synthesized. The findings of the physicochemical characterization studies suggested that the hydrogel exhibited excellent formulation characteristics and showed controlled release for seven days, making it suitable for chronic wound healing studies. In subsequent studies, these formulations showed good antioxidant and antimicrobial properties, and hemocompatibility, with the least cytotoxic properties. The results of the diabetic wound healing studies showed a faster wound closure rate and improved extracellular matrix formation. These antioxidant, antimicrobial, anti-inflammatory and wound-healing properties suggest that the CG-AgNP loaded chitosan-PEG hydrogel is a promising material for novel topical formulation of diabetic wounds.

Progress in the Application of Hydrogels in Intervertebral Disc Repair: A Comprehensive Review

PURPOSE OF REVIEW

Intervertebral disc degeneration (IVDD) is a common orthopaedic disease and an important cause of lower back pain, which seriously affects the work and life of patients and causes a large economic burden to society. The traditional treatment of IVDD mainly involves early pain relief and late surgical intervention, but it cannot reverse the pathological course of IVDD. Current studies suggest that IVDD is related to the imbalance between the anabolic and catabolic functions of the extracellular matrix (ECM). Anti-inflammatory drugs, bioactive substances, and stem cells have all been shown to improve ECM, but traditional injection methods face short half-life and leakage problems.

RECENT FINDINGS

The good biocompatibility and slow-release function of polymer hydrogels are being noticed and explored to combine with drugs or bioactive substances to treat IVDD. This paper introduces the pathophysiological mechanism of IVDD, and discusses the advantages, disadvantages and development prospects of hydrogels for the treatment of IVDD, so as to provide guidance for future breakthroughs in the treatment of IVDD.

Chitosan microflower-embedded gelatin sponges for advanced wound management and hemostatic applications

The study explored the antimicrobial, antibiofilm, and hemostatic properties of chitosan microflowers (CMF) in sponge form. The main objective was to enhance the preparation of CMF by employing varying quantities of calcium chloride (CaCl2) and tripolyphosphate (TPP). CMF was then combined with gelatin (GE) in different proportions to produce three sponge samples: CMF0@GE, CMF1@GE, and CMF2@GE. The CMF had a morphology like that of a flower and produced surfaces with a porous sponge-like structure. The antibacterial activity, as determined by the zone of inhibition (ZOI), increased with greater doses of CMF. Among the tested samples, CMF2@GE had the greatest activity against Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus, and Enterococcus faecium. CMF2@GE successfully suppressed biofilm formation, decreased clotting time to an average of 212.67 s, and exhibited excellent biocompatibility by preserving over 90 % viability of human skin fibroblast cells at dosages below 100 μg/mL. The results indicated that gelatin sponges filled with CMF have considerable promise as flexible medical instruments for wound healing and infection control.

Principles and Design of Bionic Hydrogel Adhesives for Skin Wound Treatment

Over millions of years of evolution, nature has developed a myriad of unique features that have inspired the design of adhesives for wound healing. Bionic hydrogel adhesives, capable of adapting to the dynamic movements of tissues, possess superior biocompatibility and effectively promote the healing of both external and internal wounds. This paper provides a systematic review of the design and principles of these adhesives, focusing on the treatment of skin wounds, and explores the feasibility of incorporating nature-inspired properties into their design. The adhesion mechanisms of bionic adhesives are analyzed from both chemical and physical perspectives. Materials from natural and synthetic polymers commonly used as adhesives are detailed regarding their biocompatibility and degradability. The multifunctional design elements of hydrogel adhesives for skin trauma treatment, such as self-healing, drug release, responsive design, and optimization of mechanical and physical properties, are further explored. The aim is to overcome the limitations of conventional treatments and offer a safer, more effective solution for the application of bionic wound dressings.

Injectable Hydrogels in Cardiovascular Tissue Engineering

Heart problems are quite prevalent worldwide. Cardiomyocytes and stem cells are two examples of the cells and supporting matrix that are used in the integrated process of cardiac tissue regeneration. The objective is to create innovative materials that can effectively replace or repair damaged cardiac muscle. One of the most effective and appealing 3D/4D scaffolds for creating an appropriate milieu for damaged tissue growth and healing is hydrogel. In order to successfully regenerate heart tissue, bioactive and biocompatible hydrogels are required to preserve cells in the infarcted region and to bid support for the restoration of myocardial wall stress, cell survival and function. Heart tissue engineering uses a variety of hydrogels, such as natural or synthetic polymeric hydrogels. This article provides a quick overview of the various hydrogel types employed in cardiac tissue engineering. Their benefits and drawbacks are discussed. Hydrogel-based techniques for heart regeneration are also addressed, along with their clinical application and future in cardiac tissue engineering.

A comprehensive review of the application of 3D-bioprinting in chronic wound management

INTRODUCTION

Chronic wounds require more sophisticated care than standard wound care because they are becoming more severe as a result of diseases like diabetes. By resolving shortcomings in existing methods, 3D-bioprinting offers a viable path toward personalized, mechanically strong, and cell-stimulating wound dressings.

AREAS COVERED

This review highlights the drawbacks of traditional approaches while navigating the difficulties of managing chronic wounds. The conversation revolves around employing natural biomaterials for customized dressings, with a particular emphasis on 3D-bioprinting. A thorough understanding of the uses of 3D-printed dressings in a range of chronic wound scenarios is provided by insights into recent research and patents.

EXPERT OPINION

The expert view recognizes wounds as a historical human ailment and emphasizes the growing difficulties and expenses related to wound treatment. The expert acknowledges that 3D printing is revolutionary, but also points out that it is still in its infancy and has the potential to enhance mass production rather than replace it. The review highlights the benefits of 3D printing for wound dressings by providing instances of smart materials that improve treatment results by stimulating angiogenesis, reducing pain, and targeting particular enzymes. The expert advises taking action to convert the technology's prospective advantages into real benefits for patients, even in the face of resistance to change in the healthcare industry. It is believed that the increasing evidence from in-vivo studies is promising and represents a positive change in the treatment of chronic wounds toward sophisticated 3D-printed dressings.

A randomized, placebo-controlled study of chitosan gel for the treatment of chronic diabetic foot ulcers (the CHITOWOUND study)

INTRODUCTION

To assess the efficacy of a chitosan-based gel (ChitoCare) for the treatment of non-healing diabetic foot ulcers (DFUs).

RESEARCH DESIGN AND METHODS

Forty-two patients with chronic DFUs were randomized to the ChitoCare or placebo gel for a 10-week treatment period and 4-week follow-up. The primary study end point was the rate of complete wound closure at week 10, presented as relative rate.

RESULTS

Thirty patients completed the 10-week treatment and 28 completed the 4-week follow-up. The ChitoCare arm achieved 16.7% complete wound closure at week 10 vs 4.2% in the placebo arm (p=0.297), 92.0% vs 37.0% median relative reduction in wound surface area from baseline at week 10 (p=0.008), and 4.62-fold higher likelihood of achieving 75% wound closure at week 10 (p=0.012). Based on the results of the Bates-Jensen Wound Assessment Tool, the wound state at week 10 and the relative improvement from the baseline were significantly better (median 20 vs 24 points, p=0.018, and median 29.8% vs 3.6%, p=0.010, respectively).

CONCLUSIONS

ChitoCare gel increased the rate of the DFU healing process. Several secondary end points significantly favored ChitoCare gel.

TRIAL REGISTRATION NUMBER

NCT04178525.

Janus structure hydrogels: recent advances in synthetic strategies, biomedical microstructure and (bio)applications

Janus structure hydrogels (JSHs) are novel materials. Their primary fabrication methods and various applications have been widely reported. JSHs are primarily composed of Janus particles (JNPs) and polysaccharide components. They exhibit two distinct physical or chemical properties, generating intriguing characteristics due to their asymmetric structure. Normally, one side (adhesive interface) is predominantly constituted of polysaccharide components, primarily serving excellent adhesion. On the other side (functional surface), they integrate diverse functionalities, concurrently performing a plethora of synergistic functions. In the biomedical field, JSHs are widely applied in anti-adhesion, drug delivery, wound healing, and other areas. It also exhibits functions in seawater desalination and motion sensing. Thus, JSHs hold broad prospects for applications, and they possess significant research value in nanotechnology, environmental science, healthcare, and other fields. Additionally, this article proposes the challenges and future work facing these fields.

Self-Healing Guar Gum-Based Nanocomposite Hydrogel Promotes Infected Wound Healing through Photothermal Antibacterial Therapy

Preventing bacterial infections is a crucial aspect of wound healing. There is an urgent need for multifunctional biomaterials without antibiotics to promote wound healing. In this study, we fabricated a guar gum (GG)-based nanocomposite hydrogel, termed GBTF, which exhibited photothermal antibacterial therapy for infected wound healing. The GBTF hydrogel formed a cross-linked network through dynamic borate/diol interactions between GG and borax, thereby exhibiting simultaneously self-healing, adaptable, and injectable properties. Additionally, tannic acid (TA)/Fe3+ nanocomplexes (NCs) were incorporated into the hydrogel to confer photothermal antibacterial properties. Under the irradiation of an 808 nm near-infrared laser, the TA/Fe3+ NCs in the hydrogel could rapidly generate heat, leading to the disruption of bacterial cell membranes and subsequent bacterial eradication. Furthermore, the hydrogels exhibited good cytocompatibility and hemocompatibility, making them a precandidate for preclinical and clinical applications. Finally, they could significantly promote bacteria-infected wound healing by reducing bacterial viability, accelerating collagen deposition, and promoting epithelial remodeling. Therefore, the multifunctional GBTF hydrogel, which was composed entirely of natural substances including guar gum, borax, and polyphenol/ferric ion NCs, showed great potential for regenerating infected skin wounds in clinical applications.

Emerging trends and challenges in polysaccharide derived materials for wound care applications: A review

Polysaccharides are favourable and promising biopolymers for wound care applications due to their abundant natural availability, low cost and excellent biocompatibility. They possess different functional groups, such as carboxylic, hydroxyl and amino, and can easily be modified to obtain the desirable properties and various forms. This review systematically analyses the recent progress in polysaccharides derived materials for wound care applications, emphasizing the most commonly used cellulose, chitosan, alginate, starch, dextran and hyaluronic acid derived materials. The distinctive attributes of each polysaccharide derived wound care material are discussed in detail, along with their different forms, i.e., films, membranes, sponges, nanoemulsions, nanofibers, scaffolds, nanocomposites and hydrogels. The processing methods to develop polysaccharides derived wound care materials are also summarized. In the end, challenges related to polysaccharides derived materials in wound care management are listed, and suggestions are given to expand their utilization in the future to compete with conventional wound healing materials.

Synthesis of novel bioadhesive hydrogels via facile Thiol-Ene click chemistry for wound healing applications

Development of outstanding, cost-effective and elastic hydrogels as bioadhesive using Thiol-Ene click chemistry was verified. The visible light photocrosslinkable hydrogels composed of methacrylated chitosan/2,2'-(Ethylenedioxy) diethanethiol formed in presence of eosin-Y photoinitiator. Such hydrogels hold great promise for wound healing applications due to their tunable properties. Main components of hydrogels were extensively characterized using spectroscopic techniques for chemical analysis, thermal analysis, and topologic nanostructure. Various optimization conditions for best gelation time were investigated. Mechanical properties of tensile strength and elongation at break (%) were verified for best wound healing applications. Optimum hydrogel was subjected to for cytotoxicity and microbial suppression evaluation and in-vivo wound healing test for efficient wound healing evaluations. Our results demonstrate the potential use of injectable hydrogels as valuable bioadhesives in bioengineering and biomedical applications, particularly in wound closure and patches.

Chitosan-based injectable hydrogel with multifunction for wound healing: A critical review

Different types of clinical wounds are difficult to treat while infected by bacteria. Wound repair involves multiple cellular and molecular interactions, which is a complicated process. However, wound repair often suffers from abnormal cellular functions or pathways that result in unavoidable side effects, so there is an urgent need for a material that can heal wounds quickly and with few side effects. Based on these needs, hydrogels with injectable properties have been confirmed to be able to undergo self-healing, which provides favorable conditions for wound healing. Notably, as a biopolymer with excellent easy-to-modify properties from a wide range of natural sources, chitosan can be used to prepare injectable hydrogel with multifunction for wound healing because of its outstanding flowability and injectability. Especially, chitosan-based hydrogels with marked biocompatibility, non-toxicity, and bio-adhesion properties are ideal for facilitating wound healing. In this review, the characteristics and healing mechanisms of different wounds are briefly summarized. In addition, the preparation and characterization of injectable chitosan hydrogels in recent years are classified. Additionally, the bioactive properties of this type of hydrogel in vitro and in vivo are demonstrated, and future trend in wound healing is prospected.

A comprehensive review on recent progress in chitosan composite gels for biomedical uses

Chitosan (CS) composite gels have emerged as promising materials with diverse applications in biomedicine. This review provides a concise overview of recent advancements and key aspects in the development of CS composite gels. The unique properties of CS, such as biocompatibility, biodegradability, and antimicrobial activity, make it an attractive candidate for gel-based composites. Incorporating various additives, such as nanoparticles, polymers, and bioactive compounds, enhances the mechanical, thermal, and biological and other functional properties of CS gels. This review discusses the fabrication methods employed for CS composite gels, including blending and crosslinking, highlighting their influence on the final properties of the gels. Furthermore, the uses of CS composite gels in tissue engineering, wound healing, drug delivery, and 3D printing highlight their potential to overcome a number of the present issues with drug delivery. The biocompatibility, antimicrobial properties, electroactive, thermosensitive and pH responsive behavior and controlled release capabilities of these gels make them particularly suitable for biomedical applications. In conclusion, CS composite gels represent a versatile class of materials with significant potential for a wide range of applications. Further research and development efforts are necessary to optimize their properties and expand their utility in pharmaceutical and biomedical fields.

Co electrospinning -poly (vinyl alcohol)-chitosan/gelatin-poly (ϵ-caprolacton) nanofibers for diabetic wound-healing application

With the increasing prevalence of diabetes, the healing of diabetic wounds has become a significant challenge for both healthcare professionals and patients. Recognizing the urgent need for effective solutions, it is crucial to develop suitable scaffolds specifically tailored for diabetic wound healing. In line with this objective, we have developed novel hybrid nanofibrous scaffolds by combining polyvinyl alcohol/chitosan (PVA/CS) and gelatin/poly(ε-caprolactone) (Gel/PCL) polymers through a double-nozzle electrospinning technique. In this study, we investigated the influence of the Gel/PCL blend ratio on the properties of the resulting nanofibers. Three different hybrid scaffold structures were examined: Gel/PCL (80:20)-PVA/CS (80:20), Gel/PCL (50:50)-PVA/CS (80:20), and Gel/PVA (20:80)-PVA/CS (80:20). Our findings demonstrate that the electrospun nanofibers of PVA/CS (80:20)-Gel/PCL (80:20) exhibited optimal mechanical performance, with a contact angle of approximately 54° and a diameter of 183 nm. Considering the crucial role of inhibiting bacterial adhesion in the success of implanted materials, we evaluated the cytocompatibility of the hybrid electrospun nanofibers using mouse fibroblast cells (L-929 cells). The in vitro cytotoxicity results obtained from L-929 fibroblast cell culture on the hybrid scaffolds revealed enhanced cell proliferation and appropriate cell morphology on the PVA/CS (80:20)-Gel/PCL (80:20) sample, indicating its capability to support tissue cell integration. Based on the information obtained from this study, the fabricated hybrid scaffold holds great promise for diabetic ulcer healing. Its optimal mechanical properties, suitable contact angle, and favorable cytocompatibility highlight its potential as a valuable tool in the field of diabetic wound healing. The development of such hybrid scaffolds represents a significant step forward in addressing the challenges associated with diabetic wound care.

Incorporation of Resveratrol-Hydroxypropyl-β-Cyclodextrin Complexes into Hydrogel Formulation for Wound Treatment

Resveratrol could be applied in wound healing therapies because of its antioxidant, anti-inflammatory and antibacterial effects. However, the main limitation of resveratrol is its low aqueous solubility. In this study, resveratrol was included in hydroxypropyl-β-cyclodextrin complexes and further formulated in Pluronic F-127 hydrogels for wound treatment therapy. IR-spectroscopy and XRD analysis confirmed the successful incorporation of resveratrol into complexes. The wound-healing ability of these complexes was estimated by a scratch assay on fibroblasts, which showed a tendency for improvement of the effect of resveratrol after complexation. The antimicrobial activity of resveratrol in aqueous dispersion and in the complexes was evaluated on methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli, and Candida albicans strains. The results revealed a twofold decrease in the MIC and stronger inhibition of the metabolic activity of MRSA after treatment with resveratrol in the complexes compared to the suspended drug. Furthermore, the complexes were included in Pluronic hydrogel, which provided efficient drug release and appropriate viscoelastic properties. The formulated hydrogel showed excellent biocompatibility which was confirmed via skin irritation test on rabbits. In conclusion, Pluronic hydrogel containing resveratrol included in hydroxypropyl-β-cyclodextrin complexes is a promising topical formulation for further studies directed at wound therapy.

Therapeutic Potential of Nanocarrier Mediated Delivery of Peptides for Wound Healing: Current Status, Challenges and Future Prospective

Wound healing presents a complex physiological process that involves a sequence of events orchestrated by various cellular and molecular mechanisms. In recent years, there has been growing interest in leveraging nanomaterials and peptides to enhance wound healing outcomes. Nanocarriers offer unique properties such as high surface area-to-volume ratio, tunable physicochemical characteristics, and the ability to deliver therapeutic agents in a controlled manner. Similarly, peptides, with their diverse biological activities and low immunogenicity, hold great promise as therapeutics in wound healing applications. In this review, authors explore the potential of peptides as bioactive components in wound healing formulations, focusing on their antimicrobial, anti-inflammatory, and pro-regenerative properties. Despite the significant progress made in this field, several challenges remain, including the need for standardized characterization methods, optimization of biocompatibility and safety profiles, and translation from bench to bedside. Furthermore, developing multifunctional nanomaterial-peptide hybrid systems represents promising avenues for future research. Overall, the integration of nanomaterials made up of natural or synthetic polymers with peptide-based formulations holds tremendous therapeutic potential in advancing the field of wound healing and improving clinical outcomes for patients with acute and chronic wounds.

Synthesis and characterization of mupirocin-LDH/PVA nanofibrous composite as a dual-carrier drug release system

Nowadays, nanofibrous structures based on organic and inorganic materials are considered a drug delivery system for the controlled release of antibiotics and other antibacterial agents. The main goal of this research is a combination of the special properties of nanofibrous structure and Mupirocin-loaded Layered double hydroxide (LDH) to obtain a dual-carrier drug release system to provide long term antibacterial properties in wound healing process. Regards, unloaded layered double hydroxide (LDH) and Mupirocin-loaded LDH, which were synthesized by co-precipitation method, were added to Polyvinyl alcohol (PVA) solution in different mass ratio and electrospun using different processing conditions. The physico-chemical characterizations were performed using SEM, FTIR and tensile strength tests. The biological properties of the fabricated nanocomposites were evaluated using antibacterial test and in vitro cell culturing followed by MTT assay. The SEM results showed a bead-less and uniform morphology of nanofibrous composite containing Mupirocin(2.3 wt%)-LDH(15 wt%)/PVA with an average fiber diameter of about 270 ± 58 nm. According to the release study, the maximum release of the mupirocin drug was about 54 % in the first 6 h. The antibiogram analysis exhibited good antibacterial activity of mupirocin-loaded nanocomposite against both bacteria, especially gram-positive one. Finally, MTT assay approved the biocompatibility of the mupirocin-loaded nanocomposite. Overall, the produced nanofibrous composites would be a promising dual-carrier system for controlled release of antibiotic.

Biomedical Trends in Stimuli-Responsive Hydrogels with Emphasis on Chitosan-Based Formulations

Biomedicine is constantly evolving to ensure a significant and positive impact on healthcare, which has resulted in innovative and distinct requisites such as hydrogels. Chitosan-based formulations stand out for their versatile utilization in drug encapsulation, transport, and controlled release, which is complemented by their biocompatibility, biodegradability, and non-immunogenic nature. Stimuli-responsive hydrogels, also known as smart hydrogels, have strictly regulated release patterns since they respond and adapt based on various external stimuli. Moreover, they can imitate the intrinsic tissues' mechanical, biological, and physicochemical properties. These characteristics allow stimuli-responsive hydrogels to provide cutting-edge, effective, and safe treatment. Constant progress in the field necessitates an up-to-date summary of current trends and breakthroughs in the biomedical application of stimuli-responsive chitosan-based hydrogels, which was the aim of this review. General data about hydrogels sensitive to ions, pH, redox potential, light, electric field, temperature, and magnetic field are recapitulated. Additionally, formulations responsive to multiple stimuli are mentioned. Focusing on chitosan-based smart hydrogels, their multifaceted utilization was thoroughly described. The vast application spectrum encompasses neurological disorders, tumors, wound healing, and dermal infections. Available data on smart chitosan hydrogels strongly support the idea that current approaches and developing novel solutions are worth improving. The present paper constitutes a valuable resource for researchers and practitioners in the currently evolving field.

Rapid eradication of vancomycin and methicillin-resistant Staphylococcus aureus by MDP1 antimicrobial peptide coated on photocrosslinkable chitosan hydrogel: in vitro antibacterial and in silico molecular docking studies

Introduction

Antibiotic resistance and weak bioavailability of antibiotics in the skin due to systemic administration leads to failure in eradication of vancomycin- and methicillin-resistant Staphylococcus aureus (VRSA and MRSA)-associated wound infections and subsequent septicemia and even death. Accordingly, this study aimed at designing a photocrosslinkable methacrylated chitosan (MECs) hydrogel coated by melittin-derived peptide 1 (MDP1) that integrated the antibacterial activity with the promising skin regenerative capacity of the hydrogel to eradicate bacteria by burst release strategy.

Methods

The MECs was coated with MDP1 (MECs-MDP1), characterized, and the hydrogel-peptide interaction was evaluated by molecular docking. Antibacterial activities of MECs-MDP1 were evaluated against VRSA and MRSA bacteria and compared to MECs-vancomycin (MECs-vanco). Antibiofilm activity of MECs-MDP1 was studied by our novel 'in situ biofilm inhibition zone (IBIZ)' assay, and SEM. Biocompatibility with human dermal fibroblast cells (HDFs) was also evaluated.

Results and Discussion

Molecular docking showed hydrogen bonds as the most interactions between MDP1 and MECs at a reasonable affinity. MECs-MDP1 eradicated the bacteria rapidly by burst release strategy whereas MECs-vanco failed to eradicate them at the same time intervals. Antibiofilm activity of MECs-MDP1 were also proved successfully. As a novel report, molecular docking analysis has demonstrated that MDP1 covers the structure of MECs and also binds to lysozyme with a reasonable affinity, which may explain the inhibition of lysozyme. MECs-MDP1 was also biocompatible with human dermal fibroblast skin cells, which indicates its safe future application. The antibacterial properties of a photocrosslinkable methacrylated chitosan-based hydrogel coated with MDP1 antimicrobial peptide were successfully proved against the most challenging antibiotic-resistant bacteria causing nosocomial wound infections; VRSA and MRSA. Molecular docking analysis revealed that MDP1 interacts with MECs mainly through hydrogen bonds with reasonable binding affinity. MECs-MDP1 hydrogels eradicated the planktonic state of bacteria by burst release of MDP1 in just a few hours whereas MECs-vanco failed to eradicate them. inhibition zone assay showed the anti-biofilm activity of the MECs-MDP1 hydrogel too. These findings emphasize that MECs-MDP1 hydrogel would be suggested as a biocompatible wound-dressing candidate with considerable and rapid antibacterial activities to prevent/eradicate VRSA/MRSA bacterial wound infections.

Bringing innovative wound care polymer materials to the market: Challenges, developments, and new trends

The development of innovative products for treating acute and chronic wounds has become a significant topic in healthcare, resulting in numerous products and innovations over time. The growing number of patients with comorbidities and chronic diseases, which may significantly alter, delay, or inhibit normal wound healing, has introduced considerable new challenges into the wound management scenario. Researchers in academia have quickly identified promising solutions, and many advanced wound healing materials have recently been designed; however, their successful translation to the market remains highly complex and unlikely without the contribution of industry experts. This review article condenses the main aspects of wound healing applications that will serve as a practical guide for researchers working in academia and industry devoted to designing, evaluating, validating, and translating polymer wound care materials to the market. The article highlights the current challenges in wound management, describes the state-of-the-art products already on the market and trending polymer materials, describes the regulation pathways for approval, discusses current wound healing models, and offers a perspective on new technologies that could soon reach consumers. We envision that this comprehensive review will significantly contribute to highlighting the importance of networking and exchanges between academia and healthcare companies. Only through the joint of these two actors, where innovation, manufacturing, regulatory insights, and financial resources act in harmony, can wound care products be developed efficiently to reach patients quickly and affordably.

Chitosan and neem gum-based polyelectrolyte complex for design of allantoin loaded biocomposite film: In-vitro, ex-vivo, and in-vivo characterization

Presently, the preference for chitosan (CS) and gum polysaccharides in biomedical applications including drug delivery and wound healing has been extensively documented. Despite this, the demerits of CS and gum polysaccharides such as poor mechanical properties, degradation rate, swelling, etc., limit their applications for designing biocomposite films for drug delivery. Therefore, the anticipated work aims to design a CS and neem gum polysaccharides (NGP) polyelectrolyte complex-based allantoin (AT)-loaded (CS/NGP-AT) biocomposite film for improved wound healing. In brief, CS, NGP, and CS/NGP-AT-based biocomposite films were prepared using the solvent-casting method, and in-vitro, ex-vivo, and in-vivo characterizations were performed to assess the performance of these biocomposite films compared to their counterparts. In this, diffractogram and thermogram analysis assured the conversion of crystalline AT into an amorphous form. The optimized CS/NGP/AT-3 formulation exhibited controlled water absorption, appropriate water uptake capacity, good water retention ability, excellent water vapor transmission rate, controlled degradation rate, enhanced mechanical properties, cell and blood biocompatibility, etc. Furthermore, it offered improved antimicrobial, anti-inflammatory, and antioxidant potential. The optimized film provided a modified release (88.3 ± 0.3 %) of AT from the film for up to 48 h. Wound healing experiments on rats and their histopathology studies confirmed a significantly higher rate of wound recovery within 14 days compared to the control and CS/NGP film, attributable to the combined effects of CS, NGP, and AT. In conclusion, the fabricated CS/NGP-based biocomposite film presents promising prospects as an excellent candidate for wound healing applications.

A review on natural biopolymers in external drug delivery systems for wound healing and atopic dermatitis

Despite the advantages of topical administration in the treatment of skin diseases, current marketed preparations face the challenge of the skin's barrier effect, leading to low therapeutic effectiveness and undesirable side effects. Hence, in recent years the management of skin wounds, the main morbidity-causing complication in hospital environments, and atopic dermatitis, the most common inflammatory skin disease, has become a great concern. Fortunately, new, more effective, and safer treatments are already under development, with chitosan, starch, silk fibroin, agarose, hyaluronic acid, alginate, collagen, and gelatin having been used for the development of nanoparticles, liposomes, niosomes and/or hydrogels to improve the delivery of several molecules for the treatment of these diseases. Biocompatibility, biodegradability, increased viscosity, controlled drug delivery, increased drug retention in the epidermis, and overall mitigation of adverse effects, contribute to an effective treatment, additionally providing intrinsic antimicrobial and wound healing properties. In this review, some of the most recent success cases of biopolymer-based drug delivery systems as part of nanocarriers, semi-solid hydrogel matrices, or both (hybrid systems), for the management of skin wounds and atopic dermatitis, are critically discussed, including composition and in vitro, ex vivo and in vivo characterization, showing the promise of these external drug delivery systems.

Laminin mimetic angiogenic and collagen peptide hydrogel for enhance dermal wound healing

Laminins are essential in basement membrane architecture and critical in re-epithelialization and angiogenesis. These processes and collagen deposition are vital in skin wound healing. The role of angiogenic peptides in accelerating the wound-healing process has been known. The bioactive peptides could be a potential approach due to their similar effects as growth factors and inherent biocompatible and biodegradable nature with lower cost. They can also recognize ligand-receptor interaction and mimic the extracellular matrix. Here, we report novel angiogenic DYVRLAI, CDYVRLAI, angiogenic-collagen PGPIKVAV, and Ac-PGPIKVAV peptides conjugated sodium carboxymethyl cellulose hydrogel, which was designed from laminin. The designed peptide exhibits a better binding with the α3β1, αvβ3, and α5β1 integrins and CXCR2 receptor, indicating their angiogenic and collagen binding efficiency. The peptides were evaluated to stimulate wound healing in full-thickness excision wounds in normal and diabetic mice (type II). They demonstrated their efficacy in terms of angiogenesis (CD31), re-epithelialization through regeneration of the epidermis (H&E), and collagen deposition (MT). The synthesized peptide hydrogel (DYVRLAI and CDYVRLAI) showed enhanced wound contraction up to 10.1 % and 12.3 % on day 7th compared to standard becaplermin gel (49 %) in a normal wound model. The encouraging results were also observed with the diabetic model, where these peptides showed a significant decrease of 5.20 and 5.17 % in wound size on day 10th compared to the commercial gel (9.27 %). These outcomes signify that the modified angiogenic peptide is a cost effective, novel peptide motif to promote dermal wound healing in both models.

Chitosan-based hydrogels: From preparation to applications, a review

Chitosan, derived from the deacetylation of chitin, is an abundant natural biopolymer on earth. Chitosan and its derivatives have become promising biological materials because of their unique molecular structure and excellent biological activities. The reactive functional groups of chitosan such as the amino and hydroxyl groups play a crucial role in facilitating the synthesis of three-dimensional hydrogel. Chitosan-based hydrogels have been widely used in medical, pharmaceutical, and environmental fields for years. Nowadays, chitosan-based hydrogels have been found in a wide range of applications in the food industry such as food sensors, dye adsorbents and nutrient carriers. In this review, recently developed methods for the preparation of chitosan-based hydrogels were given, and the biological activities of chitosan-based hydrogels were systematically introduced. Additionally, the recent progress in food sensors, packaging, dye adsorbents, and nutrient carriers was discussed. Finally, the challenges and prospects for the future development of chitosan-based hydrogels were discussed.

A review of the current state of natural biomaterials in wound healing applications

Skin, the largest biological organ, consists of three main parts: the epidermis, dermis, and subcutaneous tissue. Wounds are abnormal wounds in various forms, such as lacerations, burns, chronic wounds, diabetic wounds, acute wounds, and fractures. The wound healing process is dynamic, complex, and lengthy in four stages involving cells, macrophages, and growth factors. Wound dressing refers to a substance that covers the surface of a wound to prevent infection and secondary damage. Biomaterials applied in wound management have advanced significantly. Natural biomaterials are increasingly used due to their advantages including biomimicry of ECM, convenient accessibility, and involvement in native wound healing. However, there are still limitations such as low mechanical properties and expensive extraction methods. Therefore, their combination with synthetic biomaterials and/or adding bioactive agents has become an option for researchers in this field. In the present study, the stages of natural wound healing and the effect of biomaterials on its direction, type, and level will be investigated. Then, different types of polysaccharides and proteins were selected as desirable natural biomaterials, polymers as synthetic biomaterials with variable and suitable properties, and bioactive agents as effective additives. In the following, the structure of selected biomaterials, their extraction and production methods, their participation in wound healing, and quality control techniques of biomaterials-based wound dressings will be discussed.

CSMP: A Self-Assembled Plant Polysaccharide-Based Hydrofilm for Enhanced Wound Healing

Wound management remains a critical healthcare issue due to the rising incidence of chronic diseases leading to persistent wounds. Traditional dressings have their limitations, such as potential for further damage during changing and suboptimal healing conditions. Recently, hydrogel-based dressings have gained attention due to their biocompatibility, biodegradability, and ability to fill wounds. Particularly, polysaccharide-based hydrogels have shown potential in various medical applications. This study focuses on the development of a novel hydrofilm wound dressing produced from a blend of chia seed mucilage (CSM) and polyvinyl alcohol (PVA), termed CSMP. While the individual properties of CSM and PVA are well-documented, their combined potential in wound management is largely unexplored. CSMP, coupled with sorbitol and glycerin, and cross-linked using ultraviolet light, results in a flexible, adhesive, and biocompatible hydrofilm demonstrating superior water absorption, moisturizing, and antibacterial properties. This hydrofilm promotes epithelial cell migration, enhanced collagen production, and outperforms existing commercial dressings in animal tests. The innovative CSMP hydrofilm offers a promising, cost-effective approach for improved wound care, bridging existing gaps in dressing performance and preparation simplicity. Future research can unlock further applications of such polysaccharide-based hydrofilm dressings.

Glycosaminoglycans' Ability to Promote Wound Healing: From Native Living Macromolecules to Artificial Biomaterials

Glycosaminoglycans (GAGs) are important for the occurrence of signaling molecules and maintenance of microenvironment within the extracellular matrix (ECM) in living tissues. GAGs and GAG-based biomaterial approaches have been widely explored to promote in situ tissue regeneration and repair by regulating the wound microenvironment, accelerating re-epithelialization, and controlling ECM remodeling. However, most approaches remain unacceptable for clinical applications. To improve insights into material design and clinical translational applications, this review highlights the innate roles and bioactive mechanisms of native GAGs during in situ wound healing and presents common GAG-based biomaterials and the adaptability of application scenarios in facilitating wound healing. Furthermore, challenges before the widespread commercialization of GAG-based biomaterials are shared, to ensure that future designed and constructed GAG-based artificial biomaterials are more likely to recapitulate the unique and tissue-specific profile of native GAG expression in human tissues. This review provides a more explicit and clear selection guide for researchers designing biomimetic materials, which will resemble or exceed their natural counterparts in certain functions, thereby suiting for specific environments or therapeutic goals.

Exploring polysaccharide-based bio-adhesive topical film as a potential platform for wound dressing application: A review

Wound dressings act as a physical barrier between the wound site and the external environment, preventing additional harm; choosing suitable wound dressings is essential for the healing process. Polysaccharide biopolymers have demonstrated encouraging findings and therapeutic prospects in recent decades about wound therapy. Additionally, polysaccharides have bioactive qualities like anti-inflammatory, antibacterial, and antioxidant capabilities that can help the process of healing. Due to their excellent tissue adhesion, swelling, water absorption, bactericidal, and immune-regulating properties, polysaccharide-based bio-adhesive films have recently been investigated as intriguing alternatives in wound management. These films also mimic the structure of the skin and stimulate the regeneration of the skin. This review presented several design standards and functions of suitable bio-adhesive films for the healing of wounds. Additionally, the most recent developments in the use of bio-adhesive films as wound dressings based on polysaccharides, including hyaluronic acid, chondroitin sulfate, dextran, alginate, chitosan, cellulose, konjac glucomannan, gellan gum, xanthan gum, pectin, guar gum, heparin, arabinogalactans, carrageen, and tragacanth gum, are thoroughly discussed. Lastly, to create a road map for the function of polysaccharide-based bio-adhesive films in advanced wound care, their clinical performances and future challenges in making bio-adhesive films by three-dimensional bioprinting are summarized.

Pharmaceutical applications of chitosan in skin regeneration: A review

Skin regeneration is the process that restores damaged tissues. When the body experiences trauma or surgical incisions, the skin and tissues on the wound surface become damaged. The body repairs this damage through complex physiological processes to restore the original structural and functional states of the affected tissues. Chitosan, a degradable natural bioactive polysaccharide, has attracted widespread attention partly owing to its excellent biocompatibility and antimicrobial properties; additionally, a modified form of this compound has been shown to promote skin regeneration. This review evaluates the recent research progress in the application of chitosan to promote skin regeneration. First, we discuss the basic principles of the extraction and preparation processes of chitosan from its source. Subsequently, we describe the functional properties of chitosan and the optimization of these properties through modification. We then focus on the existing chitosan-based biomaterials developed for clinical applications and their corresponding effects on skin regeneration, particularly in cases of diabetic and burn wounds. Finally, we explore the challenges and prospects associated with the use of chitosan in skin regeneration. Overall, this review provides a reference for related research and contributes to the further development of chitosan-based products in cutaneous skin regeneration.

Chitosan Hydrogel Dressing Loaded with Adipose Mesenchymal Stem Cell-Derived Exosomes Promotes Skin Full-Thickness Wound Repair

Cutaneous trauma repair is still a challenge in the clinic due to the scar formation and slow healing rate, especially for diabetic patients. Various drug-loading wound dressings have been explored to solve this problem. Mesenchymal stem cell (MSC)-derived exosomes have been considered as a potential cell-free drug because of their anti-inflammation function and tissue repair property that are comparable to that of MSCs. Herein, a composite wound dressing (Exo/Gel) consisting of the chitosan hydrogel and adipose MSC-derived exosome (ADMSC-Exo) was designed and fabricated by a physical mixing method to promote the skin full-thickness wound repair. The exosomes were slowly released from the Exo/Gel dressing with the degradation of the chitosan hydrogel. The Exo/Gel displayed enhanced cell migration and angiogenic properties in vitro. And the results in the rat skin wound model showed that the Exo/Gel could promote the regular collagen deposition, angiogenesis, and hair follicle mosaicism regeneration. These results proved that the hydrogel dressing with ADMSCs-derived exosomes can accelerate skin wound healing, which is a strategy for developing wound dressings.

Construction methods and biomedical applications of PVA-based hydrogels

Polyvinyl alcohol (PVA) hydrogel is favored by researchers due to its good biocompatibility, high mechanical strength, low friction coefficient, and suitable water content. The widely distributed hydroxyl side chains on the PVA molecule allow the hydrogels to be branched with various functional groups. By improving the synthesis method and changing the hydrogel structure, PVA-based hydrogels can obtain excellent cytocompatibility, flexibility, electrical conductivity, viscoelasticity, and antimicrobial properties, representing a good candidate for articular cartilage restoration, electronic skin, wound dressing, and other fields. This review introduces various preparation methods of PVA-based hydrogels and their wide applications in the biomedical field.

Fabrication of Bilayer Nanofibrous-Hydrogel Scaffold from Bacterial Cellulose, PVA, and Gelatin as Advanced Dressing for Wound Healing and Soft Tissue Engineering

Tissue engineering is currently one of the fastest-growing areas of engineering, requiring the fabrication of advanced and multifunctional materials that can be used as scaffolds or dressings for tissue regeneration. In this work, we report a bilayer material prepared by electrospinning a hybrid material of poly(vinyl alcohol) (PVA) and bacterial cellulose (BC NFs) (top layer) over a highly interconnected porous 3D gelatin-PVA hydrogel obtained by a freeze-drying process (bottom layer). The techniques were combined to produce an advanced material with synergistic effects on the physical and biological properties of the two materials. The bilayer material was characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and a water contact measurement system (WCMS). Studies on swelling, degradability, porosity, drug release, cellular and antibacterial activities were performed using standardized procedures and assays. FTIR confirmed cross-linking of both the top and bottom layers, and SEM showed porous structure for the bottom layer, random deposition of NFs on the surface, and aligned NFs in the cross section. The water contact angle (WCA) showed a hydrophilic surface for the bilayer material. Swelling analysis showed high swelling, and degradation analysis showed good stability. The bilayer material released Ag-sulfadiazine in a sustained and controlled manner and showed good antibacterial activities against severe disease-causing gram + ive and -ive (Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa) bacterial strains. In vitro biological studies were performed on fibroblasts (3T3) and human embryonic kidneys (HEK-293), which showed desirable cell viability, proliferation, and adhesion to the bilayer. Thus, the synergistic effect of NFs and the hydrogel resulted in a potential wound dressing material for wound healing and soft tissue engineering.

In Vitro and In Vivo Evaluation of Chitosan/HPMC/Insulin Hydrogel for Wound Healing Applications

Treatment of chronic wounds is challenging, and the development of different formulations based on insulin has shown efficacy due to their ability to regulate oxidative stress and inflammatory reactions. The formulation of insulin with polysaccharides in biohybrid hydrogel systems has the advantage of synergistically combining the bioactivity of the protein with the biocompatibility and hydrogel properties of polysaccharides. In this study, a hydrogel formulation containing insulin, chitosan, and hydroxypropyl methyl cellulose (Chi/HPMC/Ins) was prepared and characterized by FTIR, thermogravimetric, and gel point analyses. The in vitro cell viability and cell migration potential of the Chi/HPMC/Ins hydrogel were evaluated in human keratinocyte cells (HaCat) by MTT and wound scratch assay. The hydrogel was applied to excisional full-thickness wounds in diabetic mice for twenty days for in vivo studies. Cell viability studies indicated no cytotoxicity of the Chi/HPMC/Ins hydrogel. Moreover, the Chi/HPMC/Ins hydrogel promoted faster gap closure in the scratch assay. In vivo, the wounds treated with the Chi/HPMC/Ins hydrogel resulted in faster wound closure, formation of a more organized granulation tissue, and hair follicle regeneration. These results suggest that Chi/HPMC/Ins hydrogels might promote wound healing in vitro and in vivo and could be a new potential dressing for wound healing.

Hydrogel-Based Skin Regeneration

The skin is subject to damage from the surrounding environment. The repair of skin wounds can be very challenging due to several factors such as severe injuries, concomitant infections, or comorbidities such as diabetes. Different drugs and wound dressings have been used to treat skin wounds. Tissue engineering, a novel therapeutic approach, revolutionized the treatment and regeneration of challenging tissue damage. This field includes the use of synthetic and natural biomaterials that support the growth of tissues or organs outside the body. Accordingly, the demand for polymer-based therapeutic strategies for skin tissue defects is significantly increasing. Among the various 3D scaffolds used in tissue engineering, hydrogel scaffolds have gained special significance due to their unique properties such as natural mimicry of the extracellular matrix (ECM), moisture retention, porosity, biocompatibility, biodegradability, and biocompatibility properties. First, this article delineates the process of wound healing and conventional methods of treating wounds. It then presents an examination of the structure and manufacturing methods of hydrogels, followed by an analysis of their crucial characteristics in healing skin wounds and the most recent advancements in using hydrogel dressings for this purpose. Finally, it discusses the potential future advancements in hydrogel materials within the realm of wound healing.

Confronting antibiotic-resistant pathogens: Distinctive drug delivery potentials of progressive nanoparticles

Antimicrobial resistance arises over time, usually due to genetic modifications. Global observations of high resistance rates to popular antibiotics used to treat common bacterial diseases, such as diarrhea, STIs, sepsis, and urinary tract infections, indicate that our supply of effective antibiotics is running low. The mechanisms of action of several antibiotic groups are covered in this review. Antimicrobials disrupt the development and metabolism of bacteria, leading to their eventual death. However, in recent years, microorganisms become resistant to the drugs. Bacteria encode resistant genes against antibiotics and inhibit the function of antibiotics by reducing the uptake of drugs, modifying the enzyme's active site, synthesizing enzymes to degrade antibiotics, and changing the structure of ribosomal subunits. Additionally, the methods of action of resistant bacteria against different kinds of antibiotics as well as their modes of action are discussed. Besides, the resistant pathogenic bacteria which get the most priority by World Health Organisation (WHO) for synthesizing new drugs, have also been incorporated. To overcome antimicrobial resistance, nanomaterials are used to increase the efficacy of antimicrobial drugs. Metallic, inorganic, and polymer-based nanoparticles once conjugated with antibacterial drugs, exhibit synergistic effects by increasing the efficacy of the drugs by inhibiting bacterial growth. Nanomaterial's toxic properties are proportional to their concentrations. Higher concentration nanomaterials are more toxic to the cells. In this review, the toxic properties of nanomaterials on lung cells, lymph nodes, and neuronal cells are also summarized.

Direct ink writing of biocompatible chitosan/non-isocyanate polyurethane/cellulose nanofiber hydrogels for wound-healing applications

The demand for new biocompatible and 3D printable materials for biomedical applications is on the rise. Ideally, such materials should exhibit either biodegradability or recyclability, possess antibacterial properties, and demonstrate remarkable biocompatibility with no cytotoxic effects. In this research, we synthesized biocompatible and 3D printable hydrogels tailored for biomedical applications, such as wound healing films, by combining antibacterial double-quaternized chitosan (DQC) with cystamine-based non-isocyanate polyurethane (NIPU-Cys) - a material renowned for enhancing both the flexibility and mechanical properties of the hydrogels. To improve the rheological behavior, swelling attributes, and printability, cellulose nanofibrils were introduced into the matrix. We investigated the impact of DQC on degradability, swelling capacity, rheological behavior, printability, and cell biocompatibility. The slightly cytotoxic nature associated with quaternary chitosan was evaluated, and the optimal concentration of DQC in the hydrogel was determined to ensure biocompatibility. The resulting hydrogels were found to be suitable materials for 3D printing via a direct ink writing technique (DIW), producing porous, biocompatible hydrogels endowed with valuable attributes suitable for various wound-healing applications.

Recent advances in production of sustainable and biodegradable polymers from agro-food waste: Applications in tissue engineering and regenerative medicines

Agro-food waste is a rich source of biopolymers such as cellulose, chitin, and starch, which have been shown to possess excellent biocompatibility, biodegradability, and low toxicity. These properties make biopolymers from agro-food waste for its application in tissue engineering and regenerative medicine. Thus, this review highlighted the properties, processing methods, and applications of biopolymers derived from various agro-food waste sources. We also highlight recent advances in the development of biopolymers from agro-food waste and their potential for future tissue engineering and regenerative medicine applications, including drug delivery, wound healing, tissue engineering, biodegradable packaging, excipients, dental applications, diagnostic tools, and medical implants. Additionally, it explores the challenges, prospects, and future directions in this rapidly evolving field. The review showed the evolution of production techniques for transforming agro-food waste into valuable biopolymers. However, these biopolymers serving as the cornerstone in scaffold development and drug delivery systems. With their role in wound dressings, cell encapsulation, and regenerative therapies, biopolymers promote efficient wound healing, cell transplantation, and diverse regenerative treatments. Biopolymers support various regenerative treatments, including cartilage and bone regeneration, nerve repair, and organ transplantation. Overall, this review concluded the potential of biopolymers from agro-food waste as a sustainable and cost-effective solution in tissue engineering and regenerative medicine, offering innovative solutions for medical treatments and promoting the advancement of these fields.

Pyrogallol loaded chitosan-based polymeric hydrogel for controlling Acinetobacter baumannii wound infections: Synthesis, characterization, and topical application

Antibacterial hydrogels have emerged as a promising approach for wound healing, owing to their ability to integrate antibacterial agents into the hydrogel matrix. Benefiting from its remarkable antibacterial and wound-healing attributes, pyrogallol has been introduced into chitosan-gelatin for the inaugural development of an innovative antibacterial polymeric hydrogel tailored for applications in wound healing. Hence, we observed the effectiveness of pyrogallol in inhibiting the growth of A. baumannii, disrupting mature biofilms, and showcasing robust antioxidant activity both in vitro and in vivo. In addition, pyrogallol promoted the migration of human epidermal keratinocytes and exhibited wound healing activity in zebrafish. These findings suggest that pyrogallol holds promise as a therapeutic agent for wound healing. Interestingly, the pyrogallol-loaded chitosan-gelatin (Pyro-CG) hydrogel exhibited enhanced mechanical strength, stability, controlled drug release, biodegradability, antibacterial activity, and biocompatibility. In vivo results established that Pyro-CG hydrogel promotes wound closure and re-epithelialization in A. baumannii-induced wounds in molly fish. Therefore, the prepared Pyro-CG polymeric hydrogel stands poised as a potent and promising agent for wound healing with antibacterial properties. This holds considerable promise for the development of effective therapeutic interventions to address the increasing menace of A. baumannii-induced wound infections.

Comparative Analysis of Antibacterial and Wound Healing Activities of Chitosan and Povidone-Iodine-Based Hydrogels

PURPOSE

This study aimed to compare the antibacterial and wound healing efficacies of chitosan hydrogel with povidone-iodine (PI) hydrogel.

METHODS

The in vitro antibacterial activities of chitosan and PI hydrogels against Staphylococcus aureus and Escherichia coli were evaluated. Nine 6- to 8-week-old male Sprague-Dawley rats were divided into plain, PI, and chitosan hydrogel groups. Each rat received two 10-mm full-thickness dorsal wounds using an excisional splinting model. Each wound was treated with 0.2 mL of gel thrice over the course of 3 postoperative weeks. Weekly observations were conducted, and at the end of the third postoperative week, the rats were killed for histopathological and quantitative polymerase chain reaction evaluations. Data analysis included both 2- and 1-way analyses of variance.

RESULTS

Chitosan hydrogel exhibited comparable in vitro antibacterial activity and a significantly enhanced in vivo wound closure rate compared with PI hydrogel. Three weeks after the surgery, the chitosan hydrogel group demonstrated marked differences in wound repair (P < 0.01). Histologically, increased collagen deposition was observed with chitosan hydrogel treatment. Immunohistochemistry for CD68 revealed a lower number of macrophages in the wounds treated with chitosan hydrogel. Quantitative polymerase chain reaction analysis indicated a superior collagen 1 to 3 ratio and reduced expression of proinflammatory cytokine mRNAs (interleukin 1b, interleukin 6, tumor necrosis factor α, and interferon γ) in the chitosan hydrogel group.

CONCLUSION

Chitosan hydrogel demonstrates the potential to serve as an effective alternative to PI hydrogel, providing enhanced wound healing capabilities while maintaining comparable antimicrobial properties.

Banana fibre-chitosan-guar gum composite as an alternative wound healing material

Bio-composites, which can be obtained from the renewable natural resources, are fascinating material for use as sustainable biomaterials with essential properties like biodegradable, bio-compatibility as well cyto-compatibility etc. These properties are useful for bio-medical including wound healing applications. In this study, fibre obtained banana pseudo stem of banana plant, which is otherwise wasted, was used as a material along with chitosan and guar gum to fabricate a banana fibre-biopolymer composite patch. The physiochemical properties of the patches were examined using Fourier Transformed Infra-red spectrophotometer (FT-IR), tensile tester, Scanning Electron Microscope (SEM), contact angle tester, swelling and degradation studies. We further demonstrated that a herbal drug, Nirgundi could be loaded to the patch showed controlled its release at different pHs. The patch had good antibacterial property and supported proliferation of mouse fibroblast cells. The study thus indicates that banana fibre-chitosan-guar gum composite can be developed into an alternative wound healing material.

Chitosan-Based Biomaterial in Wound Healing: A Review

Wound healing is an evolving and intricate technique that is vital to the restoration of tissue integrity and function. Over the past few decades, chitosan a biopolymer derived from chitin, became known as an emerging biomaterial in the field of healing wounds due to its distinctive characteristics including biocompatibility, biodegradability, affinity to biomolecules, and wound-healing activity. This natural polymer exhibits excellent healing capabilities by accelerating the development of new skin cells, reducing inflammation, and preventing infections. Due to its distinct biochemical characteristics and innate antibacterial activity, chitosan has been extensively researched as an antibacterial wound dressing. Chronic wounds, such as diabetic ulcers and liver disease, are a growing medical problem. Chitosan-based biomaterials are a promising solution in the domain of wound care. The article analyzes the depth of chitosan-based biomaterials and their impact on wound healing and also the methods to enhance the advantages of chitosan by incorporating bioactive compounds. This literature review is aimed to improve the understanding and knowledge about biomaterials and their use in wound healing.

Natural agents as wound-healing promoters

The management of acute and chronic wounds resulting from diverse injuries poses a significant challenge to clinical practices and healthcare providers. Wound healing is a complex biological process driven by a natural physiological response. This process involves four distinct phases, namely hemostasis, inflammation, proliferation, and remodeling. Despite numerous investigations on wound healing and wound dressing materials, complications still persist, necessitating more efficacious therapies. Wound-healing materials can be categorized into natural and synthetic groups. The current study aims to provide a comprehensive review of highly active natural animal and herbal agents as wound-healing promoters. To this end, we present an overview of in vitro, in vivo, and clinical studies that led to the discovery of potential therapeutic agents for wound healing. We further elucidated the effects of natural materials on various pharmacological pathways of wound healing. The results of previous investigations suggest that natural agents hold great promise as viable and accessible products for the treatment of diverse wound types.

Tissue adhesives based on chitosan for skin wound healing: Where do we stand in this era? A review

Chitosan has been commonly used as an adhesive dressing material due to its excellent biocompatibility, degradability, and renewability. Tissue adhesives are outstanding among wound dressings because they can close the wound, absorb excess tissue exudate from the wound site, provide a moist environment, and act as a carrier for loading various bioactive molecules. They have been widely used in both preclinical and clinical treatment of skin wounds. This review summarizes recent research progresses in the application of chitosan and its derivatives for tissue adhesives. We also introduce their biomedical effects on wound adhesion, contamination isolation, antibacterial, immune regulation, and wound healing, and the strategies to achieve these functions when used as wound dressings. Finally, challenges and future perspectives of chitosan-based tissue adhesives are discussed for wound healing.

Application of Chitosan-Based Hydrogel in Promoting Wound Healing: A Review

Chitosan is a linear polyelectrolyte with active hydroxyl and amino groups that can be made into chitosan-based hydrogels by different cross-linking methods. Chitosan-based hydrogels also have a three-dimensional network of hydrogels, which can accommodate a large number of aqueous solvents and biofluids. CS, as an ideal drug-carrying material, can effectively encapsulate and protect drugs and has the advantages of being nontoxic, biocompatible, and biodegradable. These advantages make it an ideal material for the preparation of functional hydrogels that can act as wound dressings for skin injuries. This review reports the role of chitosan-based hydrogels in promoting skin repair in the context of the mechanisms involved in skin injury repair. Chitosan-based hydrogels were found to promote skin repair at different process stages. Various functional chitosan-based hydrogels are also discussed.

Fucoidan loaded PVA/Dextran blend electrospun nanofibers for the effective wound healing

Chronic wounds have become a serious global health issue. In this study, we investigated the effect of increasing fucoidan (FD) concentration on the characteristics of nanofibers and their wound healing potential at in vitro as well as in vivo level. The results showed that increasing FD content (0.25 to 1 %) led to an significant increase in nanofiber diameter (487.7 ± 125.39 to 627.9 ± 149.78 nm), entrapment efficiency (64.26 ± 2.6 to 94.9 ± 3.1 %), and water uptake abilities (436.5 ± 1.2 to 679.7 ± 11.3 %). However, the in vitro biodegradation profile decreased with an increase in FD concentration. Water vapor transmission rate analysis showed that it was within the standard range for all FD concentrations. Nanofibers with 1 % PVA/DX/FD exhibited slow-release behavior, suggesting prolonged FD availability at the wound site. In vivo studies in rats with full-thickness wounds demonstrated that applying 1 % FD-enriched PVA/DEX nanofibers significantly (p < 0.0001) improved mean wound area closure. These findings suggest that FD-enriched nanofibers have immense potential as a wound dressing material in future if explored further.

Injectable Chitosan-Methoxy Polyethylene Glycol Hybrid Hydrogel Untangling the Wound Healing Behavior: In Vitro and In Vivo Evaluation

Wound healing, particularly for difficult-to-treat wounds, presents a serious threat and may lead to complications. Currently available dressings lack mucoadhesion, safety, efficacy, and, most importantly, patient compliance. Herein, we developed a unique, simple, and inexpensive injectable chitosan-methoxy polyethylene glycol (chitosan-mPEG) hybrid hydrogel with tunable physicochemical and mechanical properties for wound healing. The detailed physicochemical and rheological characterization of the chitosan-mPEG hydrogel has revealed chemical interaction between available -NH2 groups of chitosan and -COOH groups of mPEG acid, which, to our perspective, enhanced the mechanical and wound healing properties of hybrid chitosan and mPEG hydrogel compared to solo chitosan or PEG hydrogel. By introducing mPEG, the wound healing ability of hydrogel is synergistically improved due to its antibacterial feature, together with chitosan's innate role in hemostasis and wound closure. The detailed hemostasis and wound closure potential of the chitosan-mPEG hydrogel were investigated in a rat model, which confirmed a significant acceleration in wound healing and ultimately wound closure. In conclusion, the developed chitosan-mPEG hydrogel met all the required specifications and could be developed as a promising material for hemostasis, especially wound management, and as an excellent candidate for wound healing application.

Hydrogels and Wound Healing: Current and Future Prospects

The care and rehabilitation of acute and chronic wounds have a significant social and economic impact on patients and global health. This burden is primarily due to the adverse effects of infections, prolonged recovery, and the associated treatment costs. Chronic wounds can be treated with a variety of approaches, which include surgery, negative pressure wound therapy, wound dressings, and hyperbaric oxygen therapy. However, each of these strategies has an array of limitations. The existing dry wound dressings lack functionality in promoting wound healing and exacerbating pain by adhering to the wound. Hydrogels, which are commonly polymer-based and swell in water, have been proposed as potential remedies due to their ability to provide a moist environment that facilitates wound healing. Their unique composition enables them to absorb wound exudates, exhibit shape adaptability, and be modified to incorporate active compounds such as growth factors and antibacterial compounds. This review provides an updated discussion of the leading natural and synthetic hydrogels utilized in wound healing, details the latest advancements in hydrogel technology, and explores alternate approaches in this field. Search engines Scopus, PubMed, Science Direct, and Web of Science were utilized to review the advances in hydrogel applications over the last fifteen years.