Supporting role of silica nanospheres with surface modified by silver nanoparticles in antibacterial photodynamic therapy (APDT), was studied. Optical and antibacterial properties of a photosensitizer Photolon (R) in the presence of silica based nanopowders doped with silver nanoparticles, were determined. Various concentrations of Photolon (R) solution and nanomaterials have been prepared in order to examine the optical absorption and the effectivity of antibacterial activity. It was found that the maximum optical absorption of Photolon (R) depends on its concentration and can be enhanced by the presence of silver nanoparticles. The presence of silver nanoparticles can thus lead to a reduction of the concentration of the photosensitizer while achieving the same level of antibacterial efficacy as in case of higher photosensitizer concentration without the presence of silver nanoparticles. Efficiency of APDT was enhanced by combination of nanosilver doped silica nanospheres, which have powerful antimicrobial and bactericidal activity and photoactive photosensitizer - Photolon (R). (C) 2018 Published by Elsevier B.V.