Dose dependency and kinetics. Dose dependency (A) and kinetic (B) analyses of the visible-light induced bactericidal activity against S. aureus of TiO2-related photocatalyst substrates were shown. Illumination was carried out either at different light densities for 5 min (A) or at a light density of 3 × 104 lux for different times (B). In each illumination condition, the percentages of the surviving bacteria in C150 and C200 groups were normalized to the percentage of the surviving bacteria in the UV100 groups (100%). * P < 0.05 and ** P < 0.01 compared to the respective UV100 groups. + P < 0.05 compared to the respective C150 groups.