Comparison of light emitting diodes and semiconductor laser inducing photodynamic therapy of cancer cells in vitro

摘要

The goal of anticancer therapy is achievement of balance between destruction of tumour cells and tissues and conservation of physiological functions of noncancer cells. Photodynamic therapy (PDT) is one of novel alternative treatment modality of malignant neoplasms. This method is based on cytotoxic action of excited sensitizers in the oxygen-rich environment. Sensitizers bound to cells and are excited by light source identical to absorption maximum of sensitizer. Photodynamic reactions lead to production of reactive oxygen species (ROS), which cause necrosis or apoptosis of cancer cells. The objective of our work was to analyse of phototoxicity in the sense of DNA damage in cancer cells after PDT by single cell gell electrophoresis (SCGE, comet assay) using ZnTPPS4 (zinc(II)-5,10,15,20-tetrakis(4-sulphonatophenyl) porphyrine and disulfonated chloraluminium phthalocyanine ClAlPcS2 as sensitizers. Violet light emitting diodes (LEDs; 1.5 mJ.cm~(-2).s~(-1); 418 nm) and semiconductor laser (50mW; 675 nm) were used as sources of radiation. Level of DNA fragmentation was detected after application of different light doses.