Cold Atmospheric Plasma-Assisted Deposition of Ammonium Functionalized Glass Coating for Enhanced Antibacterial Properties

Abstract

Implant-associated bacterial infections are a major healthcare concern that significantly impacts patient health, leading to increased morbidity, extended hospital stays, and substantial economic burden. The rise of antibiotic-resistant bacterial strains further complicates treatment protocols, as these resistance mechanisms often exhibit enhanced bacterial pathogenicity and virulence. A key strategy to address this challenge involves the development of antibacterial surface modifications for implantable devices that provide broad-spectrum efficacy against various opportunistic bacterial pathogens while preserving biocompatibility. In this context, the present work focuses on the conformal deposition of ammonium compounds -infused glass ceramic coatings using Cold Atmospheric Plasma (CAP) technology. The air plasma-based process facilitates the in-situ polymerization and direct deposition of glass composite coatings on a wide range of polymeric and metallic surfaces under atmospheric conditions. To identify the optimal composition of ammonium compounds in the SiOx matrix for effective chemical bonding while simultaneously providing antibacterial properties, a systematic study of various processing precursor compositions was conducted. A series of material characterization and chemical surface composition studies, including SEM, EDX, and XPS, were employed to determine the effective plasma process parameters, final composition, and chemical bonding characteristics of the SiOx matrix. Results show that increased infusion of APS leads to enhanced covalent bonding within the matrix, resulting in stronger SiOx crosslinking in the functional coating. Additionally, among the various precursor compositions, at least 0.6 wt.% APS is necessary within the SiOx matrix to provide broad-spectrum antibacterial efficacy against two common implant-associated bacterial pathogens, Escherichia coli and Staphylococcus aureus, while also ensuring biocompatibility. It is envisioned that the developed CAP technology will enable a scalable, rapid, and low-temperature deposition of antibacterial coatings for both temporary and permanent implants, aimed at reducing current complications associated with such infections.