Abstract
TiO&sub2; nanoparticles modified with phthalocyanines (Pc) have been proven to be a potential photosensitizer in the application of photodynamic therapy (PDT). However, the generation of reactive oxygen species (ROS) by TiO&sub2; nanoparticles modified with Pc has not been demonstrated clearly. In this study, nitrogen-doped TiO&sub2; conjugated with Pc (N-TiO&sub2;-Pc) were studied by means of monitoring the generation of ROS. The absorbance and photokilling effect on HeLa cells upon visible light of different regions were also studied and compared with non-doped TiO&sub2;-Pc and Pc. Both N-TiO&sub2;-Pc and TiO&sub2;-Pc can be activated by visible light and exhibited much higher photokilling effect on HeLa cells than Pc. In addition, nitrogen-doping can greatly enhance the formation of ¹O&sub2; and •O&sub2;-, while it suppresses the generation of OH•. This resulted in significant photodynamic activity. Therefore, N-TiO&sub2;-Pc can be an excellent candidate for a photosensitizer in PDT with wide-spectrum visible irradiation.