Light-activated hybrid organic/inorganic antimicrobial coatings

Light-activated antimicrobial coatings were obtained by the covalently immobilizing photo-sensitizers in a hybrid organic/inorganic matrix. These coatings were deposited via sol-gel chemistry using epoxy and methyl functional silanes. The light-activated chromophores used in this study were Methylene Blue, Toluidine Blue O, and Rose Bengal. The immobilized photo-sensitizers did not leach from the coatings. The mechanically durable hybrid coatings comprising 2.5% by weight of Rose Bengal had a good adhesion to the glass surface. These coatings were tested for the photo-deactivation of Escherichia coli and Staphylococcus aureus using illumination by a commercial fluorescent lamp. Log reduction of E. coli and S. aureus were > 4 when illuminated by the fluorescent lamp in 1 and 3 h, respectively. Due to its high mechanical durability and chemical resistance, such light-activated hybrid coatings are promising candidates for indoor applications in healthcare facilities. [GRAPHICS] Antimicrobial surfaces are obtained by the chemical immobilization of photo-sensitizers in hybrid materials. The coatings had killing rates > 4.4 in log reduction against E. coli and S. aureus after illumination with a fluorescent lamp for < 3 h. The adhesion of the coatings to the glass was good and they were stratch resistant and did not change even after three cycles of autoclave sterilization.