Light-activated antimicrobial surfaces with enhanced efficacy induced by a dark-activated mechanism†
Novel bactericidal surfaces were prepared by incorporating crystal violet, methylene blue and 2 nm gold nanoparticles into medical grade silicone using a simple dipping technique. The modified polymers were stable to cleaning by use of an alcohol-based wipe and demonstrated good photostability under intense illumination conditions. The photobactericidal activity of this polymer was compared against a range of other photobactericidal polymers against both Staphylococcus epidermidis and Escherichia coli, under white lighting conditions comparable to that found in a clinical environment. Not only did this novel multi-dye–nanogold–polymer exhibit the strongest photobactericidal activity reported to date, surprisingly, it also demonstrated significant antimicrobial activity under dark conditions.