The biocidal activity of silver loaded TiO2 suspension, characterized by XRD,
UV-Vis spectroscopy, TEM images, and ED pattern, was systematically investigated in the presence
of BLB irradiation. The study shows that the presence of silver nano-particles on TiO2 surfaces
contributes the significantly enhanced inactivation of E. coli with BLB irradiation. The apparent E.
coli inactivation observed without BLB irradiation indicates the bactericidal activity of Ag nanoparticle
itself. In mechanistic aspects, the adsorption of Ag/TiO2 particles on E. coli surface and the
disruption of the surface components of E. coli, such as the cell wall, cell membrane, etc., were
directly observed by SEM and TEM images. These cell surface decompositions would be caused by
the reaction with Ag nano-particles itself and the surface alteration activity of monosulfide radical,
produced from the reaction between silver and cystein of cell under light irradiation.
