مریم شریفی - Dept. of Cell & Molecular Biology, Islamic Azad University Pharmaceutical Sciences Branch, Tehran, Iran
سید محمد امین موسوی - Division of Medical Biotechnology, National Institute for Genetic Engineering and Biotechnology, Tehran, Iran
طاهره ناجی - Dept. of Cell & Molecular Biology, Islamic Azad University Pharmaceutical Sciences Branch, Tehran, Iran

Backgrounds and Objective: Titanium dioxide (TiO۲) is a potent photosensitizer in photodynamic therapy (PDT) and is activated upon ultraviolet (UV) irradiation.The aim of this study was the assessment of the effect of nitrogen –nano doped of titanium dioxide in human A-۳۷۵ melanoma cancer cell line. Materials and Methods: N-TiO۲ nanoparticles were prepared by mechanical mixing of urea with TiO۲ powder in a ۴:۱ weight ratio. A-۳۷۵ cells were treated with different concentrations of N-TiO۲ for various time intervals in the presence or absence of visible light. The growth and viability of A-۳۷۵ cells were determined by means of trypan blue exclusion test and MTT assay, respectively. Acridine orange/Ethidium bromide double staining and DNA gel electrophoresis were applied to determine apoptosis. Results: The results showed that visible light activated N-TiO۲ could induce growth inhibition in a dose (۰.۰۱-۱۰۰ μg/ml ) and time dependent manner. In concentration of ۰.۵ μg/ml a significant difference was observed between the treated and the control samples.Decrease in viability was observed in ۱۰۰ μg/ml concentration and the results of fluorescent microscopy showed  DNA fragmentation due to apoptotic cell death[G۱]  at this concentration. Conclusion: Based on the anti-cancer effects of N-TiO۲ on A-۳۷۵ cells, further evaluation of these nanoparticles as a new photosensitizer in photocatalytic therapy of skin cancer can be proposed.

Keywords: Melanoma, Nitrogen doping, Photodynamic therapy, Titanium dioxide