Different photodynamic effect between continuous wave and pulsed laser irradiation modes in k562 cells in vitro

Abstract

Photodynamic therapy is a cancer treatment method is used primarily continuous mode laser radiation. At high power density irradiation occurs intense consumption of molecular oxygen and this caused hypoxic tumor tissue, which leads to inefficiency PDT. In this paper, pulsed and continuous irradiation modes during PDT photosensitizer Radachlorin were compared. A mathematical model for the generation of singlet oxygen 1O2 in tumor cells during photodynamic therapy with tissue oxygenation was developed. Our study theoretically and experimentally demonstrates the increased singlet oxygen generation efficiency in a pulsed irradiation mode compared to continuous wave mode with the same power density 20mW/cm2. Experimental in vitro showed that pulsed irradiation mode mostly induces apoptosis k562 tumor cells at irradiation doses of k562 1.25 - 2.5J/cm2 while the continuous mode induced necrosis.