Distribution and photobleaching of photosensitizer chlorophyll derivative (CPD) in SMCF7 cancer cells

Photodynamic therapy (PDT) is a promising new treatment modality for several diseases, most notably cancer. In PDT, light, O2, and photosensitizer are combined to produce a selective therapeutic effect. Chlorophyll derivative photosensitizer(CPD) is the class of new photosensitizers for photodynamic therapy ( PDT) . And to date, little is known about the interaction between the photosensitizer and the inner parts of tumor cell in PDT. A fluorescent microscopy and imaging study on CPD was performed. To observe the dynamic process of how the photosensitizer (CPD) enters the tumor cell and intracellular distribution of CPD in tumor cells, we used confocal laser scan microscopy(CLSM) under one-photon excitation induced by a 488nm Ar+ laser. We also obtained the fluorescence photobleaching of CPD in cells with varied intensity of excitation laser(488nm). By means of CLSM, we found most of the photosensitize CPD distribute in on nuclear membrane but few in nuclear.