FIG. 3.

Protein- and light-absorbing substances. The effects of BSA (A), bromophenol blue dye (B), and bacterial concentrations (C) on the bactericidal activity of the TiO₂-related substrates after visible-light illumination are shown. The percentages of surviving bacteria were normalized to the percentage of the surviving bacteria on the TiO₂ substrate plus 5% BSA (A), to that on the TiO₂ substrate plus 2 OD of dye (B), or to that from 2 OD of E. coli on the TiO₂ substrate (C). *, P < 0.05 compared to the group with TiO₂ plus 5% BSA (A), the group with TiO₂ plus 2 OD of dye (B), or the group with 2 OD of E. coli on TiO₂ (C); **, P < 0.01 compared to the group with TiO₂ plus 5% BSA (A) or the group with TiO₂ plus 2 OD of dye (B).