Solvent-Free Cold Plasma Deposition of PVA-Antibiotic Films: Influence of Process Parameters on Coating Structure and Drug Release

Abstract

Post-operative infections remain a challenge in implant surgery, leading to prolonged treatment, increased costs, and implant failure. Localized antibiotic-delivery coatings are a promising strategy to reduce infection risk while maintaining biocompatibility. Here, we evaluate cold atmospheric pressure plasma (CAP) spraying as a solvent-free method to deposit polyvinyl alcohol (PVA) layers containing amikacin on stainless steel and to identify plasma parameters that control release and antibacterial activity. A 3 × 3 factorial design varied nozzle distance (15, 20, 25 mm) and speed (10, 15, 20 cm/s). Surface morphology was assessed by optical microscopy, amikacin release quantified by HPLC-HRMS, and antibacterial activity tested against Staphylococcus aureus and Escherichia coli using Kirby–Bauer disc diffusion. Two-way ANOVA with Tukey post hoc tests and nonparametric validation were applied. Cold plasma spraying speed significantly affected drug release, whereas distance and the interaction term were not significant. Lower spraying speeds produced thicker, more porous coatings with greater cumulative release and larger inhibition zones. Drug release profiles were best described by Weibull and first-order models, showing an initial burst followed by sustained release. These findings indicate that CAP spraying enables solvent-free fabrication of antibiotic-loaded PVA coatings with tunable release, and optimizing spraying speed improves coating mass, drug delivery, and antibacterial performance.

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