Antibacterial and Biocompatible Hydrogel Dressing Based on Gelatin- and Castor-Oil-Derived Biocidal Agent

Favored antibacterial activity associated with excellent biocompatibility, mechanical durability, and exudate handling needs to be addressed by modern dressing to achieve the desired wound healing. This paper deals with developing a new green and facile approach to manufacturing nonleachable antibacterial gelatin-based films for wound dressing. Therefore, a reactive methoxy-silane-functionalized quaternary ammonium compound bearing a fatty amide residue originating from castor oil (Si-CAQ) was initially synthesized. The antibacterial dressings were then fabricated via sol-gel and condensation reactions of the mixture containing gelatin, Si-CAQ, (3-glycidyloxypropyl) trimethoxysilane, and poly(vinyl alcohol). By utilizing bioactive polymers as starting materials and eliminating organic solvents during the dressing preparation, desirable clinical safety could be ensured. The gelatin-based films presented appropriate mechanical properties, such as flexibility and strength, in both dried and hydrated states (tensile strength >6 MPa and elongation >100). It is due to the in situ generations of the inorganic silicon domain in the organic framework via the sol-gel cross-linking process. The prepared dressings exhibited desirable features, including excellent biocompatibility (cell viability >95%), proper wound-exudate-managing characteristics (equilibrium water contact (EWA) 280-350% and water vapor transmission rate (WVTR) 2040-2200 g/m²/day), fluid handling capacity (FHC) (3-3.35 g), as well as commendable hemocompatibility. The promising bactericidal activity of the dressing against Bacillus subtilis, methicillin-resistant Staphylococcus aureus, and Escherichia coli strains with a contact-killing efficacy of 100% could prevent infection development at the wounded area. As evaluated by the wound scratch assay, the desired fibroblast cell growth, migration, and proliferation indicated the capability of the dressing to facilitate the healing process by encouraging fibroblast cell migration to the damaged area. In vivo wound-healing results showed that the prepared biocidal dressing stimulates wound healing and enhances epithelialization, collagen maturation, and vascularization of wounds due to their antibacterial effects and accelerated cellular functions.