TiO2 nanoparticles were synthesized using a chemical vapor condensation (CVC) method, and their physicochemical properties were characterized to optimize the synthesis conditions for antibacterial activity. The antibacterial activities of CVC-TiO2 nanoparticles and commercialized TiO2 nanoparticles (P25, Deggusa) were investigated according to UV exposure time and amount of photocatalyst. We found that the specific surface area and the crystallinity of CVC-TiO2 nanoparticles were varied depending on synthesis temperature and precursor vapor concentration. As a result, the CVC-TiO2 nanoparticles showed a higher specific surface area and better crystallinity than that of P25TiO(2). More importantly, CVC-TiO2 nanoparticles generated a larger amount of hydroxyl radicals than P25TiO(2). Consequently CVC-TiO2 nanoparticles were more effective as an antibacterial photocatalyst than P25TiO(2) under irradiation with UV light. Based-on these results, the optimum synthetic conditions of CVC-TiO2 nanoparticles for bactericidal effect were found. (C) 2011 Elsevier B.V. All rights reserved.