Polydopamine modified multifunctional carboxymethyl chitosan/pectin hydrogel loaded with recombinant human epidermal growth factor for diabetic wound healing.

The development of a multifunctional wound dressing that can adapt to the shape of wounds and provide controlled drug release is crucial for diabetic patients. This study developed a carboxymethyl chitosan-based hydrogel dressing with enhanced mechanical properties and tissue adherence that were achieved by incorporating pectin (PE) and polydopamine (PDA) and loading the hydrogel with recombinant human epidermal growth factor (rhEGF). This EGF@PDA-CMCS-PE hydrogel demonstrated robust tissue adhesion, enhanced mechanical properties, and superior water retention and vapor permeability. It also exhibited significant antioxidant capacity. The results showed that EGF@PDA-CMCS-PE could effectively scavenge 2,2'-Azinobis-(3-ethylbenzthiazoline-6-sulphonate)， (1,1-diphenyl-2-picrylhydrazyl), and superoxide anions and increase superoxide dismutase and catalase levels in vivo. In vitro cytotoxicity and antibacterial assays showed good biocompatibility and antimicrobial properties. The sustained release of EGF by the hydrogel was confirmed, with a gradual release profile over 120 h. In vivo studies in diabetic mice showed that the hydrogel significantly accelerated wound healing, with a wound contraction rate of 97.84% by day 14. Histopathological analysis revealed that the hydrogel promoted fibroblast proliferation, neovascularization, and orderly connective tissue formation, leading to a more uniform and compact wound-healing process. Thus, EGF@PDA-CMCS-PE hydrogel presents a promising tool for managing chronic diabetic wounds, offering a valuable strategy for future clinical applications.

Chitosan-based hydrogel wound dressing: From mechanism to applications, a review.

As promising biomaterials, hydrogels are widely used in the medical engineering field, especially in wound repairing. Compared with traditional wound dressings, such as gauze and bandage, hydrogel could absorb and retain more water without dissolving or losing its three-dimensional structure, thus avoiding secondary injury and promoting wound healing. Chitosan and its derivatives have become hot research topics for hydrogel wound dressing production due to their unique molecular structure and diverse biological activities. In this review, the mechanism of wound healing was introduced systematically. The mechanism of action of chitosan in the first three stages of wound repair (hemostasis, antimicrobial properties and progranulation), the effect of chitosan deacetylation and the molecular weight on its performance are analyzed. Additionally, the recent progress in intelligent and drug-loaded chitosan-based hydrogels and the features and advantages of chitosan were discussed. Finally, the challenges and prospects for the future development of chitosan-based hydrogels were discussed.

Polylactide nanofibers delivering doxycycline for chronic wound treatment.

Chronic wounds are of high incidence, difficult to heal, and can cause serious consequences if not properly treated. Doxycycline (DCH) is a broad-spectrum antibiotic and matrix metalloproteinases inhibitor, which has prominent efficacy for chronic wound treatment. Topical DCH treatment is the common administration route for chronic wounds in clinic but may result in low therapeutic efficacy and cause skin irritation at high DCH concentration, since it is difficult to control local drug concentration in the wounds and maintain the effective DCH concentration for a long time. In this study, we prepared DCH-encapsulated polylactide (DCH/PLA) nanofibers by a simple electrospinning method. Imaging studies showed that smooth and continuous DCH/PLA nanofibers with homogeneous DCH distribution were obtained at varied DCH loading content in the range of 5-30%. Mechanical property, water vapour permeability and absorbency of these nanofibers could meet the requirement as wound dressings. By adjusting DCH loading content, the wettability of the nanofibers could be transferred from hydrophobic to hydrophilic, and the release rate of DCH could be controlled in a sustained manner from three days to two weeks. Results of cytotoxicity and antibacterial test indicated that DCH/PLA nanofibers showed good cytocompatibility to L929 mouse fibroblast cells and exhibited positive antibacterial activity against Escherichia coli, suggesting its ability to treat/prevent infectious wounds. For full-thickness wound treatment of diabetic rats, DCH/PLA nanofiber mats can speed up wound healing to a higher extent than topical DCH treatment, due to the sustained release of DCH with less side effects. Our results indicate that DCH/PLA nanofiber mats hold great potential as wound dressings for chronic wound treatment.