The effect of methylene blue/TiO2 nanocomposites on Staphylococcus aureus was evaluated by a LKB-2277 Bioactivity Monitor at 37.0 degrees C. By analyzing the thermogenic power-time curves, kinetic parameters such as the growth rate constant (k), the maximum heat power of growth phase (P-m), generation time (t(G)) and the inhibitory ratio (I) were determined. The k and P-m decrease while tG and I increases with increasing concentrations of the methylene blue/TiO2 nanocomposites added into the microbe suspension. Both k and I have linear correlations with the concentration of the methylene blue/TiO2 nanocomposites. The effect of the methylene blue sensitized-TiO2 nanocomposites on the cell damage of S. aureus was investigated by microscopic method. (C) 2010 Elsevier B.V. All rights reserved.