Antibacterial-Antioxidative Thiolated Gelatin/Methacrylated Silk Fibroin Hydrogels with Nitric Oxide Release Catalyzed by Metal-Polyphenol Nanoparticles for MRSA-Infected Wound Healing

Dual-Network Hydrogel Loaded With ROS-activated Hydrogen Sulfide Donor to Accelerate Wound Healing and Inhibit Scar Production

The wound healing process consists of four continuous and overlapping stages-hemostasis, inflammation, proliferation, and remodeling-involving a variety of cells, growth factors, and the extracellular matrix. In recent years, growing evidence has shown that enhancing endogenous hydrogen sulfide (H2S) synthesis or providing exogenous H2S can promote angiogenesis, inhibit inflammation, reduce excessive oxidative stress, and support collagen deposition. However, the administration of exogenous H2S often presents challenges related to controlling its release duration and achieving targeted delivery. To achieve controlled and site-specific delivery of H2S to the wound area, a dual-network cross-linked injectable hydrogel formed by grafted ε-poly-L-lysine (designed as EG) and oxidized dextran (OD) (EGODF) loaded with a hydrogen sulfide donor (HSDF-NH2) to study its potential in wound healing is developed. The hydrogel exhibits excellent injectability, self-healing capability, and mechanical strength. Upon reactive oxygen species (ROS) stimulation, HSDF-NH2 releases both self-reporter fluorescence (HSDG-NH2) and H2S. Changes in the self-reporter fluorescence signal reflect H2S production and its entry into the body to exert therapeutic effects. Finally, using a wound model and a hypertrophic scar repair model, it is demonstrated that EGODF hydrogel is effective in promoting wound healing and inhibiting scar production.

Preparation, antioxidant, antibacterial, and in vivo evaluation of pomegranate flower extract nanofibers based on thiolated chitosan and thiolated gelatin for treating aphthous stomatitis

Recurrent aphthous stomatitis (RAS) is a common condition that manifests as ulcerative lesions in the oral mucosa. In this study, bilayer, mucoadhesive nanofibers loaded with pomegranate flower extract (PFE) were prepared using thiolated gelatin (TGel) and thiolated chitosan (TCS) as the active layer and drug-free polycaprolactone (PCL) as the backing layer. Gelatin (Gel) and chitosan (CS) were successfully thiolated (proven by Ellman's assay, solubility, 1H NMR, FTIR, Raman spectroscopy, and XRD) and electrospun into active nanofibrous layers with a diameter of 356.9 nm. The in vitro release assay showed extended release of PFE, reaching about 57 % drug release in 48 h, fitted to the Korsmeyer-Peppas kinetics. FTIR, Raman spectroscopy, and XRD also showed the characteristic peaks of the nanofibers and their components. The nanofibers also exhibited significant hydrophilicity (contact angle of 47-49°), mucoadhesion (432.7 Pa), antioxidant capabilities (93.3 ± 0.2 %), and antibacterial effects against Staphylococcus aureus and Pseudomonas aeruginosa. Furthermore, PFE-loaded thiolated nanofibers significantly accelerated wound healing and epithelial tissue regeneration in vivo, reducing the ulcer area from 187 ± 19 mm on the 1st day to 68 ± 6 on the 7th day. Overall, bilayer PFE-loaded nanofibers based on TCS and TGel showed promising potential for treating RAS.

Electrospinning in Drug Delivery: Progress and Future Outlook

There is intense research during the past few decades to design and fabricate drug delivery systems using the electrospinning system. Electrospinning is an efficient technique to produce nanofiber materials with different dimensions and morphologies by adjusting the processing parameters. Electrospinning is becoming an innovative technology that promotes the pursuit and maintenance of human health. Herein, the review discusses the contribution of electrospinning technology in drug delivery systems, summarising the modification of the various electrospinning system configurations and the effects of the process parameters on fibers, their application in drug delivery including carrier materials, loaded drugs and their release mechanisms and illustrates their various medical applications. Finally, this review discusses the challenges, bottlenecks, and development prospects of electrospinning technology in the field of drug delivery in terms of scaling up for clinical use and exploring potential solutions to pave the way to establish electrospinning for future drug delivery systems.

Unlocking the Potential of Hybrid Nanocomposite Hydrogels: Design, Mechanical Properties and Biomedical Performances

Hybrid nanocomposite hydrogels consist of the homogeneous incorporation of nano‐objects in a hydrogel matrix. The latter, whether made of natural or synthetic materials, possesses a microporous, soft structure that makes it an ideal host for a variety of polymer and lipid‐based nano‐objects as well as metal‐ and silica‐based ones. By carefully choosing the composition and the proportions of the different constituents, hybrid hydrogels can display a wide array of properties, from simple enhancement of mechanical characteristics to specific bioactivity. This review aims to provide an overview of the state of the art in hybrid hydrogels highlighting key aspects that make them a promising choice for a variety of biomedical applications. Strategies for the preparation of hybrid hydrogels are discussed by covering the selection of individual components. The review will also explore the physico‐chemical and rheological characterization of these materials, which is essential for understanding their structure and function, ultimately satisfying specifications for the intended use. Successful examples of biomedical applications will also be presented, and the main challenges to be met will be discussed, with the aim of stimulating the research community to exploit the full potential of these materials.

Hyaluronan Scaffold Decorated with Bifunctional Peptide Promotes Wound Healing via Antibacterial and Anti-Inflammatory

The invasion of bacteria and inflammation impeded infected wounds heal. Here, a hyaluronan-based scaffold (HAG-g-C) was designed by cross-linking with gallic acid-modified gelatin to provide a protein microenvironment and decorated with cathelicidin-BF (CBF), a natural antimicrobial peptide, to remove bacterial infections and reverse the inflammatory environment. In vitro, HAG-g-C presented an antibacterial effect on Staphylococcus aureus and Escherichia coli. Meanwhile, it could drive the phenotypic switch of macrophage from M1 to M2 to accelerate tissue remodeling. In a mouse model of S. aureus-infected total skin defects, HAG-g-C inhibited the process of infection at the beginning of the wound and then regulated the M1 macrophage transformed to M2 phenotype on day 12. In addition, HAG-g-C induced collagen deposition, and reduced the expression of TNF-α, thereby significantly accelerating the reconstruction of infected wounds.

Applications of nitric oxide-releasing nanomaterials in dermatology: Skin infections and wound healing

Nitric oxide (NO) is produced in most cells in the skin and is an important regulator of essential cutaneous functions, including responses to UV irradiation, microbial defense, wound healing, melanogenesis and epidermal permeability barrier homeostasis. Harnessing the physiological activities of NO for therapeutic use is difficult because the molecule is highly reactive and unstable. A variety of exogenous NO delivery platforms have been developed and evaluated; however, they have limited clinical applications in dermatology due to instability and poor cutaneous penetration. NO-releasing nanomaterials overcome these limitations, providing targeted tissue delivery, and sustained and controlled NO release. This review provides a comprehensive and up-to-date evaluation of the use of NO-releasing nanomaterials in dermatology for the treatment of skin and soft tissue infections and wound healing.