Natural self-healing injectable hydrogels loaded with exosomes and berberine for infected wound healing

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.

Exosome-Based Therapeutics in Dermatology

Exosomes (Exos) are tiny extracellular vesicles containing a variety of active biomolecules that play important parts in intercellular communication and influence the functions of target cells. The potential of Exos in the treatment of dermatological diseases has recently been well appreciated. This review highlights the constituents, function, and delivery of Exos, with a particular focus on their applications in skin therapy. Firstly, we offer a concise overview of the biochemical properties of Exos, including their sources, structures, and internal constituents. Subsequently, the biomedical functions of Exos and the latest advances in the extraction and purification of Exos are summarized. We further discuss the modes of delivery of Exos and underscore the potential of biomaterials in this regard. Finally, we summarize the application of Exo-aided therapy in dermatology. Overall, the objective of this review is to provide a comprehensive perspective on the applications and recent advancements of Exo-based approaches in treating skin diseases, with the intention of guiding future research efforts.

An MXene nanocomposite hydrogel for enhanced diabetic infected wound healing via photothermal antibacterial properties and bioactive molecule integration

Diabetic wounds are a major clinical challenge due to their chronic, non-healing nature, which significantly impacts patients' quality of life. Traditional treatments often fail to effectively promote wound healing, highlighting the need for new biomaterials. In this study, we developed a composite hydrogel (KC@PF@TA) that combines the photothermal and antibacterial properties of Ti₃C₂Tx-Ag (Titanium carbide-silver) with the regenerative effects of paeoniflorin (PF). The hydrogel was optimized by adjusting the composition, crosslinking density, and the incorporation of nanoparticles, which enhanced its mechanical strength, photothermal conversion efficiency, antibacterial properties, and biocompatibility. The optimized hydrogel demonstrated enhanced cell proliferation, migration, and robust photothermal and antibacterial properties in vitro. In a diabetic murine model of Staphylococcus aureus-infected wounds, KC@PF@TA exhibited exceptional therapeutic benefits in antibacterial, anti-inflammatory, angiogenic, and tissue regeneration. Overall, our results suggest that composite hydrogels with controlled bioactive agent release and mechanical modulation present a promising solution for treating chronic diabetic wounds.

Material-Mediated Immunotherapy to Regulate Bone Aging and Promote Bone Repair

As the global population ages, an increasing number of elderly people are experiencing weakened bone regenerative capabilities, resulting in slower bone repair processes and associated risks of various complications. This review outlines the research progress on biomaterials that promote bone repair through immunotherapy. This review examines how manufacturing technologies such as 3D printing, electrospinning, and microfluidic technology contribute to enhancing the therapeutic effects of these biomaterials. Following this, it provides detailed introductions to various anti-osteoporosis drug delivery systems, such as injectable hydrogels, nanoparticles, and engineered exosomes, as well as bone tissue engineering materials and coatings used in immunomodulation. Moreover, it critically analyzes the current limitations of biomaterial-mediated bone immunotherapy and explores future research directions for material-mediated bone immunotherapy. This review aims to inspire new approaches and broaden perspectives in addressing the challenges of bone repair and aging by exploring innovative biomaterial-mediated immunotherapy strategies.

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.

Nanoparticle-Reinforced Hydrogel with a Well-Defined Pore Structure for Sustainable Drug Release and Effective Wound Healing

Impaired chronic wounds are a common complication of diabetes. Inhibited angiogenesis and dysfunctional inflammation render diabetic wound healing a critical challenge. Herein, a sustainable therapeutic composite hydrogel is presented for diabetic wound healing, consisting of a cocktail formulation of anti-inflammatory and local anesthetic nanoparticles incorporated into a composite hydrogel. The surface-modified drug nanoparticles are loaded into the biocompatible hydrogels and cross-linked with a gel precursor to enhance the structure. The sustainable delivery system achieves more than 90% drug release, with a total therapy duration tunable from 4 to 72 h. Through the long-lasting anti-inflammatory and analgesic effects of the composite hydrogel, diabetic wounds are swiftly transitioned into the proliferation phase, augmenting the survival and migration of keratinocytes and facilitating neovascularization and collagen alignment in diabetic wounds. These effects significantly improve the wound healing rate and skin regeneration process, achieving a healing rate that is 17 times that of untreated wounds. This study demonstrates that the hydrogel platform loaded with cocktail drug nanoparticles is promising for the rapid healing of diabetic wounds.

Thermosensitive Injectable Dual Drug-Loaded Chitosan-Based Hydrogels for Treating Bacterial Endometritis

Endometritis, a prevalent obstetric condition primarily caused by Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), significantly threatens the reproductive performance of female animals. In this study, thermosensitive injectable chitosan (CS)/β-glycerophosphate (β-GP) hydrogels loaded with berberine (BBR) and carvacrol (CAR) were prepared for endometritis treatment. In vitro, BBR/CAR-CS/β-GP hydrogels exhibited rapid gelation within 5 min at 37 °C, excellent injectability, and more than 90% degradation within 30 days under enzymatic action. The dual drug-loaded system also exhibited controlled release of BBR and CAR and demonstrated the antimicrobial activity against E. coli and S. aureus. In vivo, uterine injection of BBR/CAR-CS/β-GP hydrogels alleviated infection-induced injuries and reduced the bacterial load in infected uterine tissues. In summary, these findings highlight the potential of BBR/CAR-CS/β-GP hydrogels as innovative carriers for drug delivery targeting endometritis.

Photo-crosslinking injectable Photothermal antibacterial hydrogel based on quaternary ammonium grafted chitosan and hyaluronic acid for infected wound healing

Antibacterial hydrogels not only provide a better environment for skin wounds to avoid infection but also accelerate wound healing. Herein, chitosan modified by a quaternary ammonium salt (CQ), and hyaluronic acid grafted with methacrylate (HM) were designed and synthesized to prepare an injectable photo-crosslinking hydrogel for wound dressing with inherent antibacterial and photothermal properties. CQ and HM exhibited excellent biocompatibility, improved water retention, and antibacterial activity, illustrating vast potential as an antibacterial material in various applications. MXene, a type of 2D nanomaterial, has been widely researched due to its photothermal properties. The CQ and HM polymer precursor could be mixed with Mxene and then crosslinked with 395 nm UV radiation under mild conditions to form a 3D network structure CQ-HM/MXene hydrogel. This hydrogel displayed an appropriate swelling ratio, elastic modulus, photothermal property and excellent biocompatibility. The injectable property of the hydrogel allowed it to easily cover the wound. In vitro and in vivo studies showed that the injectable hydrogel had low cytotoxicity and excellent antibacterial properties, which could help promote wound healing. In summary, this novel CQ-HA/MXene hydrogel has the potential for application in skin wound healing due to inherent antibacterial activity and photothermal effect.

Engineering and Monitoring the Sustained Release of Extracellular Vesicles from Hydrogels for In Vivo Therapeutic Applications

Extracellular vesicles (EVs) are gaining interest in regenerative medicine and biomaterials have been shown to extend EV bioavailability following delivery. Here, we report the labeling of both hydrogels and EVs to better understand hydrogel design for sustained EV release into tissues. Shear-thinning hydrogels were engineered using guest-host (i.e., adamantane-cyclodextrin) modifications to hyaluronic acid (GH), as well as GH hydrogels with the addition of gelatin crosslinked via transglutaminase (GH+Gel) to temporally control hydrogel properties. When labeled with a near-IR dye and injected into rat myocardial tissue, the GH+Gel hydrogel was retained (>14 days) longer than the GH hydrogel alone (~7 days), likely due to the added gelatin network. To overcome challenges associated with common EV labeling methods, we utilized a highly versatile metabolic labeling methodology via the incorporation of Ac4ManNAz during EV synthesis to introduce azide groups that could then be reacted with DBCO-dyes. When injected in saline, EVs were cleared within 24 hours in hearts; however, hydrogels enhanced EV retention, with levels based on hydrogel degradation behavior, namely >14 days for GH+Gel hydrogel and ~7 days for GH hydrogel alone. These findings support the use of hydrogels in EV therapies to help retain their presence at desired tissue sites.

Recent advances in the development of chitosan/hyaluronic acid-based hybrid materials for skin protection, regeneration, and healing: A review

Biomaterials play vital roles in regenerative medicine, specifically in tissue engineering applications. They promote angiogenesis and facilitate tissue creation and repair. The most difficult aspect of this field is acquiring smart biomaterials that possess qualities and functions that either surpass or are on par with those of synthetic products. The biocompatibility, biodegradability, film-forming capacity, and hydrophilic nature of the non-sulfated glycosaminoglycans (GAGs) (hyaluronic acid (HA) and chitosan (CS)) have attracted significant attention. In addition, CS and HA possess remarkable inherent biological capabilities, such as antimicrobial, antioxidant, and anti-inflammatory properties. This review provides a comprehensive overview of the recent progress made in designing and fabricating CS/HA-based hybrid materials for dermatology applications. Various formulations utilizing CS/HA have been developed, including hydrogels, microspheres, films, foams, membranes, and nanoparticles, based on the fabrication protocol (physical or chemical). Each formulation aims to enhance the materials' remarkable biological properties while also addressing their limited stability in water and mechanical strength. Additionally, this review gave a thorough outline of future suggestions for enhancing the mechanical strength of CS/HA wound dressings, along with methods to include biomolecules to make them more useful in skin biomedicine applications.

Nanofiber-reinforced chitosan/gelatine hydrogel with photothermal, antioxidant and conductive capabilities promotes healing of infected wounds

The wound healing process was often accompanied by bacterial infection and inflammation. The combination of electrically conductive nanomaterials and wound dressings could accelerate cell proliferation through endogenous electrical signaling, effectively promoting wound healing. In this study, polypyrrole was modified with dopamine hydrochloride by an in situ polymerization to form dopamine-polypyrrole (DA-Ppy) conductive nanofibers which successfully enhanced the water dispersibility and biocompatibility of polypyrrole. The DA-Ppy nanofibers were dispersed in an aqueous solution for >48 h and still maintained good stability. In addition, the DA-Ppy nanofibers showed good photothermal properties, and the temperature could reach 59.7 °C by 1.5 W/cm2 near-infrared light irradiation (NIR) for 10 min. DA-Ppy conductive nanofibres could be well dispersed in 3,4-dihydroxyphenylpropionic acid modified chitosan-carboxymethylated β-cyclodextrin modified gelatin (CG) hydrogel due to the presence of DA, which endowed CG/DA-Ppy hydrogel with good adhesion properties, and the hydrogel adhered to the pigskin would not be dislodged by washing with running water. Under NIR, the CG/DA-Ppy hydrogel showed significant antimicrobial properties. Moreover, the CG/DA-Ppy hydrogel had excellent biocompatibility. In addition, CG/DA-Ppy hydrogel was effective in scavenging ROS, inducing macrophage polarization towards the M2 phenotype, and modulating the level of wound inflammation in vitro. Finally, it was confirmed in rat-infected wounds that the tissue regeneration effect and collagen deposition in the CG/DA-Ppy + NIR group were significantly better than the other groups in the repair of infected wounds, indicating better repair of infected wounds. The results suggested that the photothermal, antioxidant DA-Ppy conductive nanofiber had great potential for application in infected wound healing.

The Properties of Thin Films Based on Chitosan/Konjac Glucomannan Blends

In this work, blend films were prepared by blending 2% chitosan (CS) and 0.5% konjac glucomannan (KGM) solutions. Five ratios of the blend mixture were implemented (95:5, 80:20, 50:50, 20:80, and 5:95), and a pure CS film and a pure KGM film were also obtained. All the polymeric films were evaluated using FTIR spectroscopy, mechanical testing, SEM and AFM imaging, thermogravimetric analyses, swelling and degradation analyses, and contact angle measurements. The CS/KGM blends were assessed for their miscibility. Additionally, the blend films' properties were evaluated after six months of storage. The proposed blends had good miscibility in a full range of composition proportions. The blend samples, compared to the pure CS film, indicated better structural integrity. The surface structure of the blend films was rather uniform and smooth. The sample CS/KGM 20:80 had the highest roughness value (Rq = 12.60 nm). The KGM addition increased the thermal stability of films. The blend sample CS/KGM 5:95 exhibited the greatest swelling ability, reaching a swelling degree of 946% in the first fifteen minutes of the analysis. Furthermore, the addition of KGM to CS improved the wettability of the film samples. As a result of their good mechanical properties, surface characteristics, and miscibility, the proposed CS/KGM blends are promising materials for topical biomedical and cosmetic applications.

Reversible Schiff Base Chemistry in Arginine-Grafted Regenerated Cellulose Hydrogel: Integration of Chitosan and Zinc Ions for Enhanced Hemostasis, Antibacterial Action, and Accelerated Wound Healing

Wound healing presents a formidable challenge for global healthcare systems. We aimed to address this challenge by designing a multifunctional wound dressing tailored to meet diverse therapeutic needs. Arginine (Arg), selected for its ability to promote wound healing, is grafted onto aldehyde-modified regenerated cellulose (DAC) via Schiff base bonds for a reversible controlled release. At the same time, DAC provides hemostatic function, while Zn2+ plays an antibacterial role and strengthens cross-linking within the dressing matrix. The hydrogels were characterized by FTIR, XRD, SEM, and EDS. Mechanical strength, adhesion, swelling, water retention, oxygen permeability, hemostasis, antioxidant capacity, and antibacterial activity were all rigorously evaluated to demonstrate the superior properties of the dressing, which promotes accelerated wound healing. The skin of injured mice has been shown to recover almost completely within 13 days of dressing treatment. These findings highlight the potential of this innovative multifunctional wound dressing to address complex wound management challenges.

Rhein-chitosan in situ hydrogel promotes wound healing in diabetic mice

Chronic inflammation and infection often lead to delayed healing in skin wounds of patients with diabetes, presenting a significant challenge in clinical wound repair. In an effort to tackle this issue, we explored the utilization of the natural compounds Rhein and chitosan in the creation of a crosslinked in situ gel. Developed as Rhein-chitosan in situ hydrogel (CS-Rh gel), this formulation has the ability to gel at body temperature, making it suitable for irregular wounds of varying shapes. Our experimental investigations have demonstrated its excellent biocompatibility, controlled release of Rhein, biodegradability, anti-inflammatory properties, antibacterial effect, as well as its ability to enhance keratinocyte proliferation and migration. Furthermore, in vivo studies have confirmed that CS-Rh gel can effectively mitigate tissue inflammation, promote collagen deposition, and significantly accelerate wound healing in diabetic mice within a short timeframe of two weeks. Consequently, this innovative approach holds promise as a viable therapeutic strategy for supporting the healing of diabetic wounds in a clinical setting.

Green synthesis-inspired antibacterial, antioxidant and adhesive hydrogels with ultra-fast gelation and hemostasis for promoting infected skin wound healing

Bacterial infections are a serious threat to wound healing and skin regeneration. In recent years, photothermal therapy (PTT) has become one of the most promising tools in the treatment of infectious diseases. However, wound dressings with photo-responsive properties are currently still limited by the difficulties of biosafety and thermal stability brought by the introduction of photosensitizers or photothermal agents. Therefore, how to improve the therapeutic efficiency and biosafety from material design is still a major challenge at present. In this study, the carboxymethyl chitosan (CMCS) and protocatechuic aldehyde (PA) hydrogels based on horseradish peroxidase (HRP) and hydrogen peroxide (H2O2) enzymatic catalysis was developed. Therein, HRP and H2O2 catalyzed cross-linking while polymerizing PA, which not only endowed the hydrogels with photothermal responsiveness but also with good biosafety through this enzyme-catalyzed green approach. Meanwhile, the hydrogels possessed highly efficient bacteriostatic ability with the assistance of near infrared (NIR). Moreover, the ultra-rapid gelation, strong tissue adhesion, high swelling ability, good antioxidant property and hemostatic property of the CMCS-PA hydrogels based on HRP/H2O2 enzymatic catalysis were suitable for the treatment of skin wounds. Meanwhile, NIR-assistant CMCS-PA hydrogels based on HRP/H2O2 enzymatic catalysis reduced inflammation, decreased bacterial infection, and promoted collagen deposition and angiogenesis, which showed remarkable therapeutic effects in a skin wound infection model. All results indicate that this green approach to introduce photothermal property by HRP-catalyzed PA polymerization endows the hydrogels with efficient photothermal conversion efficiency, suggesting that they are promising to provide new options for replacing photothermal agents and photosensitizers. STATEMENT OF SIGNIFICANCE: In recent years, wound dressings with photo-responsive properties are currently still limited by the difficulties of biosafety and thermal stability brought by the introduction of agent photosensitizers or photothermal agents. In this study, the carboxymethyl chitosan and protocatechuic aldehyde hydrogels based on horseradish peroxidase and hydrogen peroxide enzymatic catalysis was developed. The photothermal properties of hydrogels were transformed from absent to present just by horseradish peroxidase-catalyzed protocatechuic aldehyde polymerization in a green approach. Meanwhile, the hydrogels possessed highly efficient bacteriostatic ability with the assistance of near infrared. The green approach of introducing photothermal properties from material design solves the biosafety challenge. Therefore, this study is expected to provide new options for alternative photothermal agents and photosensitizers.

Preparation of Luvangetin Nanoemulsions: Antimicrobial Mechanism and Role in Infected Wound Healing

Purpose

Incorporation of luvangetin in nanoemulsions for antimicrobial and therapeutic use in infected wound healing.

Patients and Methods

Luvangetin nanoemulsions were prepared by high-speed shear method and characterized based on their appearance structure, average droplet size, polydispersity index (PDI), electric potential, storage stability. Optimized formulation of luvangetin nanoemulsion by Box-Behnken design (BBD). The antimicrobial activity and antimicrobial mechanism of luvangetin nanoemulsions against common hospital pathogens, ie, Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), were investigated using luvangetin nanoemulsions. The biosafety of luvangetin nanoemulsion was evaluated through cytotoxicity, apoptosis, and reactive oxygen species (ROS) assay experiments using human normal epidermal cells and endothelial cells. Finally, the effect of luvangetin nanoemulsion on healing of infected wounds was investigated in B6 mice.

Results

Luvangetin nanoemulsion formulation consists of 2.5% sunflower seed oil, 10% emulsifier Span-20 and 7 minutes of shear time, and with good stability. Luvangetin nanoemulsion produces antibacterial activity against S. aureus and E. coli by disrupting the structure of bacterial cell membranes. Luvangetin nanoemulsion are biologically safe for HaCat and HUVEC. Luvangetin nanoemulsion showed good therapeutic effect on MRSA infected wounds in mice.

Conclusion

For the first time, developed a new formulation called luvangetin nanoemulsion, which exhibited superior antibacterial effects against Gram-positive bacteria. Luvangetin nanoemulsion has a favorable effect in promoting infected wound healing. We have combined luvangetin, which has multiple activities, with nanoemulsions to provide a new topical fungicidal formulation, and have comprehensively evaluated its effectiveness and safety, opening up new possibilities for further applications of luvangetin.

Ligand-Selective Targeting of Macrophage Hydrogel Elicits Bone Immune-Stem Cell Endogenous Self-Healing Program to Promote Bone Regeneration

Targeting macrophages can facilitate the site-specific repair of critical bone defects. Herein, a composite hydrogel, gelatin-Bletilla striata polysaccharide-mesoporous bioactive glass hydrogel (GBMgel), is constructed via the self-assembly of mesoporous bioactive glass on polysaccharide structures, through the Schiff base reaction. GBMgel can efficiently capture macrophages and drive the recruitment of seed stem cells and vascular budding required for regeneration in the early stages of bone injury, and the observed sustained release of inorganic silicon ions further enhances bone matrix deposition, mineralization, and vascular maturation. Moreover, the use of macrophage-depleted rat calvarial defect models further confirms that GBMgel, with ligand-selective macrophage targeting, increases the bone regeneration area and the proportion of mature bone. Mechanistic studies reveal that GBMgel upregulates the TLR4/NF-κB and MAPK macrophage pathways in the early stages and the JAK/STAT3 pathway in the later stages; thus initiating macrophage polarization at different time points. In conclusion, this study is based on the endogenous self-healing properties of bone macrophages, which enhances stem cell homing, and provides a research and theoretical basis upon which bone tissue can be reshaped and regenerated using the body's immune power, providing a new strategy for the treatment of critical bone defects.

Advancements in Regenerative Hydrogels in Skin Wound Treatment: A Comprehensive Review

This state-of-the-art review explores the emerging field of regenerative hydrogels and their profound impact on the treatment of skin wounds. Regenerative hydrogels, composed mainly of water-absorbing polymers, have garnered attention in wound healing, particularly for skin wounds. Their unique properties make them well suited for tissue regeneration. Notable benefits include excellent water retention, creating a crucially moist wound environment for optimal healing, and facilitating cell migration, and proliferation. Biocompatibility is a key feature, minimizing adverse reactions and promoting the natural healing process. Acting as a supportive scaffold for cell growth, hydrogels mimic the extracellular matrix, aiding the attachment and proliferation of cells like fibroblasts and keratinocytes. Engineered for controlled drug release, hydrogels enhance wound healing by promoting angiogenesis, reducing inflammation, and preventing infection. The demonstrated acceleration of the wound healing process, particularly beneficial for chronic or impaired healing wounds, adds to their appeal. Easy application and conformity to various wound shapes make hydrogels practical, including in irregular or challenging areas. Scar minimization through tissue regeneration is crucial, especially in cosmetic and functional regions. Hydrogels contribute to pain management by creating a protective barrier, reducing friction, and fostering a soothing environment. Some hydrogels, with inherent antimicrobial properties, aid in infection prevention, which is a crucial aspect of successful wound healing. Their flexibility and ability to conform to wound contours ensure optimal tissue contact, enhancing overall treatment effectiveness. In summary, regenerative hydrogels present a promising approach for improving skin wound healing outcomes across diverse clinical scenarios. This review provides a comprehensive analysis of the benefits, mechanisms, and challenges associated with the use of regenerative hydrogels in the treatment of skin wounds. In this review, the authors likely delve into the application of rational design principles to enhance the efficacy and performance of hydrogels in promoting wound healing. Through an exploration of various methodologies and approaches, this paper is poised to highlight how these principles have been instrumental in refining the design of hydrogels, potentially revolutionizing their therapeutic potential in addressing skin wounds. By synthesizing current knowledge and highlighting potential avenues for future research, this review aims to contribute to the advancement of regenerative medicine and ultimately improve clinical outcomes for patients with skin wounds.

Multifunctional self-healing peptide hydrogel for wound healing

The complete healing of wounds remains a challenge in clinical care. In addition, various complications such as inflammation and infection that may occur during skin wound healing can impede the healing process. Here, we constructed a multifunctional self-repairing hydrogel by utilizing Schiff base bonds. This hydrogel exhibited good self-healing properties and could cope with destructive external influences. The self-healing hydrogel was injectable, ensuring that the hydrogel dressing adhered to the wound. Carboxymethyl chitosan and oxidized chondroitin sulfate demonstrated good biocompatibility and multiple bioactivities and were successfully used to prepare self-healing hydrogels. Meanwhile, the SIKVAV biopeptide was less expensive and more morphologically stable than vascular endothelial growth factor and had a high pro-angiogenic activity. Thus, the SIKVAV biopeptide was cross-linked to the oxidized chondroitin sulfate of the hydrogel through covalent bonding to avoid rapid biopeptide degradation, achieving a slow release of the drug. This peptide hydrogel exhibited good biocompatibility and antimicrobial properties; moreover, experiments conducted on mice revealed that it could effectively promote angiogenesis and skin tissue repair. These findings suggest that the injectable self-repairing peptide hydrogel may facilitate skin wound healing and other applications.

Antibacterial microneedle patch releases oxygen to enhance diabetic wound healing

Cell growth and metabolism require an adequate supply of oxygen. However, obtaining sufficient oxygen from the blood circulating around diabetic wounds is challenging. Nevertheless, achieving a continuous and stable oxygen supply is required for these wounds to heal. Hence, in this study, we report a novel antibacterial oxygen-producing silk fibroin methacryloyl hydrogel microneedle (MN) patch comprising tips encapsulated with calcium peroxide and catalase and a base coated with antibacterial Ag nanoparticles (AgNPs). The tip of the MN patch continuously releases oxygen and inhibits the production of reactive oxygen species. This accelerates diabetic wound healing by promoting cellular accretion and migration, macrophage M2 polarization, and angiogenesis. The AgNPs at the base of the MN patch effectively combat microbial infection, further facilitating wound repair. These findings suggest that using this multifunctional oxygen-producing MN patch may be a promising strategy for diabetic wound healing in clinical settings.