Inactivation of bacterial biofilms using visible-light-activated unmodified ZnO nanorods.

Various zinc oxide (ZnO) nanostructures are widely used for photocatalytic antibacterial applications. Since ZnO possesses a wide bandgap, it is believed that only UV light may efficiently assist bacterial inactivation, and diverse crystal lattice modifications should be applied in order to narrow the bandgap for efficient visible-light absorption. In this work we show that even unmodified ZnO nanorods grown by an aqueous chemical growth technique are found to possess intrinsic defects that can be activated by visible light (λ = 405 nm) and successfully applied for total inactivation of various highly resistant bacterial biofilms rather than more sensitive planktonic bacteria.

Effective combination of LED-based visible light, photosensitizer and photocatalyst to combat Gram (-) bacteria.

The aim of this study was to investigate antimicrobial efficiency of combined treatments of visible light (405nm), chlorophyllin (Chl) and ZnO nanoparticles (NPs). Results obtained indicate that incubation of the Gram (-) Escherichia coli with Chl (1.5×10(-5)M) for 60min as well as illumination alone (405nm; 380kJ/m(2)) has no impact on the viability of E.