From Wound Dressing to Tissue Regeneration: Bilayer Medicated Patches for Personalized Treatments of Chronic Wounds.

Chronic wounds pose a significant healthcare challenge, impairing the quality of life for millions of affected individuals. This phenomenon escalates due to the aging of the population and rising comorbidities. Traditional wound care methods often prove inadequate in dealing with the complexities of chronic wounds; therefore, biomaterials have emerged as promising solutions. In response to this need, this work focuses on the development of a bilayered hybrid patch for the treatment of chronic wounds, designed with a chemical composition and morphology to exert antimicrobial activity to combat local infection and to provide specific support for cell adhesion and tissue regeneration. In particular, using gelatin and chitosan as the main constituent materials, bioactive membranes were developed and functionalized with bioresorbable hydroxyapatite nanoparticles doped with magnesium ions grown on gelatin molecules to boost regenerative stimuli. Then, they were assembled into a bilayered structure with highly tuned chemical and structural features through different fabrication techniques and biodegradation by cross-linking processes. Lastly, to confer antibacterial properties, the lower layer was medicated in situ with Vancomycin hydrochloride (VNC), selected as a case study antibiotic. The developed patches exhibit excellent physiochemical properties, including exudate absorption and moisture permeability, with both features falling within the recommended range for materials for wound healing applications. In addition, both patches exhibit adequate biodegradation times to support effective cell adhesion and proliferation, as well as drug release kinetics, with almost complete release of VNC after 48 h, necessary to achieve thorough wound disinfection. In vitro biological studies have proved their biocompatibility and on-site, long-lasting antimicrobial potential, while in vivo tests, with medicinal leeches' model, have demonstrated their affinity for live tissue and efficacy in supporting endothelial cell proliferation by stimulating the epidermal tissue healing process.