Long-term moxifloxacin release from a chitosan-based antibacterial coating on polyethylene for biomedical applications

Abstract

Medical-grade polyethylene (PE) surfaces are highly susceptible to bacterial colonization and biofilm formation, leading to hospital-associated infections (HAIs). Antibacterial coatings based on natural polymers offer a promising strategy to prevent biofilm establishment while mitigating systemic antibiotic use. However, there are some bottlenecks such as the limited duration of antimicrobial activity and the poor adhesion of the coating to the substrate. In this study, an antibacterial coating with prolonged activity was developed, based on prior work with moxifloxacin-loaded chitosan films. To promote coating adhesion, an approach consisting in wet-chemistry functionalization was studied. PE was treated with piranha solution followed by polydopamine deposition and coated with the moxifloxacin-loaded chitosan formulation. The coatings exhibited uniform coverage; piranha treatment increased roughness and enhanced hydrophilicity, allowing polymer deposition. XPS confirmed successful carbon oxidate species after piranha treatment, and enabled the identification of polydopamine and chitosan, observed by oxygen and nitrogen enrichment. Coating adhesion strength remained stable over 35 days in PBS. Antibiotic release profiles of film and coating were similar, displaying an initial burst (first 10 days) followed by sustained release of moxifloxacin. Antibacterial assay confirmed activity of the coating against S. aureus and E. coli for up to 160 days. Therefore, a wet-chemistry functionalization approach followed by polydopamine activation yields a strongly adhered antibacterial chitosan-based coating on PE that provides long-term moxifloxacin release and effective inhibition of clinically relevant pathogens. This proof-of-concept study represents a straightforward strategy to produce antimicrobial coatings with prolonged activity to reduce HAIs in medical devices.