Chitosan is a polycationic structure and an inherent antimicrobial compound. Through reactive blending, a robust and stable light-activated antimicrobial plastic that is also reusable was prepared. The antimicrobial plastic (PP-MVE-CHI) was challenged against Escherichia coli K12 while simultaneously being exposed to UV-A light for 30 min. The antimicrobial plastic retained its antimicrobial efficacy for 10 cycles, providing 94.0 ± 3.3% reduction in the microbial population across the 10 cycles. Infrared spectroscopy confirmed marginal effect on the surface chemistry after the 10 cycles. Fluorometric evaluations suggested that the antimicrobial effect was driven by reactive oxygen species generation. No evidence of fouling on the material was found through microscopic techniques. In addition, electron microscopy analysis on the bacteria exposed to this material under UV-A suggested damage to cell morphology.
Keywords: chitosan; light-activated antimicrobials; polycations; reusable antimicrobial materials.