Antibacterial nanostructured silver coating applied on polycaprolactone Melt Electrospinning Writing meshes for wound dressing application

Promoting skin regeneration and preventing infection are crucial aspects of wound healing applications. Current strategies include the use of fibrous matrices, fabricated by electrospinning, to support tissue regeneration, and the incorporation of silver (Ag), known for its antibacterial properties, to prevent infections. Here, Melt Electrospinning Writing (MEW), an innovative additive manufacturing technique, was used to fabricate porous polycaprolactone (PCL) meshes. For the first time, a silver nanocoating was deposited onto a thermos-sensitive MEW substrate by using a Physical Vacuum Deposition (PVD) method, specifically Ionized Jet Deposition. To optimize antibacterial efficacy, minimizing the potential damage to the substrate, different coating parameters were investigated. The effect of Ag deposition on morphology and composition of PCL MEW meshes was studied using scanning electron microscopy (SEM), stereomicroscopy, microtomography (μCT) and Fourier Transform InfraRed (FT-IR) spectroscopy. The MEW meshes were characterized by 500 μm squared pores with a fiber diameter around 8 μm and a porosity of 90 %. Potential detrimental effects of Ag coating on the 3D-printed MEW structures were evaluated as a function of deposition time, with no structural alteration up to 60 min. Antibacterial activity was assessed against Escherichia coli and Staphylococcus aureus strains, while cytocompatibility was confirmed by using human dermal fibroblasts. A complete antibacterial effect against E. coli cells was achieved with a deposition time > 30 min. Significant inhibition of S. aureus growth was also observed for all tested Ag coatings. The possibility to fabricate porous MEW meshes with Ag nanocoatings opens new possibilities to design innovative scaffolds for wound infection management.