Development of zein-coated Ag-NPs integrated into decellularized fish skin extracellular matrix as a hybrid scaffold for wound healing: In-vitro and in vivo study.

Chronic wounds complicated by bacterial infections and poor tissue regeneration continue to present a major clinical problem in wound healing. This work describes a new hybrid scaffold made from zein-coated silver nanoparticles (Zein-Ag NPs) embedded in decellularized fish skin extracellular matrix (ECM). This scaffold has been designed to synergistically provide antimicrobial activity and enhance tissue repair. The Ag NPs were synthesized by chemically reducing silver nitrate with sodium borohydride and then coated with zein to improve the stability and biocompatibility of the Ag NPs. Upon evaluating the Ag NPs using dynamic light scattering (DLS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD), it was determined that optimal Ag NPs were produced using a silver nitrate precursor concentration of 5 mM, which produced nanoparticles of ~35 nm in diameter. The fish skin ECM was decellularized using the optimized physical method. The Zein-Ag/ECM scaffolds exhibited strong antimicrobial activity in vitro against Candida species and bacteria, including Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, when tested using disk diffusion assays, and their controlled release of Ag⁺ minimized cytotoxicity. The biocompatibility of the material (hemocompatibility) was determined to be < 5% in vitro at 5 mM. Additionally, the material demonstrated support for the growth of fibroblasts in vitro. In vivo studies in rats showed that using the material to treat excisional wounds led to accelerated healing of the wounds, i.e., 90-95% healed by day 14, increased re-epithelialization, decreased inflammation, and improved organization of the collagen deposition in the wound site. Histopathology (using H&E and Masson Trichrome staining) confirmed this.