River (Belgium). Organic solvents were also supplied by
Sigma and were HPLC grade (St. Louis,MO). Titaniumdioxide nanoparicles
(anatase, 25 nm) were also purchased from Sigma Aldrich.
Reagents for the modified protein Lowry assay were obtained from
Pierce (Rockford, IL,USA). All other chemicalswere of the highest purity
available. Water with a typical resistivity of 18MX cm was produced
froma Milli-Q purification system (Millipore, Les Ulis, France).