Research advances in action mechanisms of photodynamic therapy and photosensitizer

Photodynamic therapy (PDT) is a noninvasive technique for diagnosis and therapy of diseases by using the photodynamic effects. Clinically, PDT has been used in the treatments of various tumors in head and neck, pancreas, lung, prostate and skin. Compared to the traditional treatments of tumors, PDT exhibits many advantages such as less damage, low toxicity, good selectivity, wide applicability and less drug resistance, which draw more attention in the field of tumor therapy. The action mechanisms of PDT against tumors are very complicated and photosensitizer is one of the key factors that influence the photodynamic effects of PDT. To enhance the tumor-targeted delivery of photosensitizer and improve their oxygen-carrying ability are believed as the important ways to increase the photodynamic effects. In this paper, review is given on the research advances in action mechanisms of photodynamic therapy and photosensitizer in recent years. Key words: Photodynamic therapy; Photosensitizer; Action mechanism