Study of the Photodynamic Activity of N-Doped TiO2 Nanoparticles Conjugated with Aluminum Phthalocyanine

TiO2 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 TiO2 nanoparticles modified with Pc has not been demonstrated clearly. In this study, nitrogen-doped TiO2 conjugated with Pc (N-TiO2-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 TiO2-Pc and Pc. Both N-TiO2-Pc and TiO2-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 1O2 and •O2−, while it suppresses the generation of OH•. This resulted in significant photodynamic activity. Therefore, N-TiO2-Pc can be an excellent candidate for a photosensitizer in PDT with wide-spectrum visible irradiation.