In vitro Effect of Methylene Blue Mediated Photodynamic Therapy on HT-29 Colon Cancer Cell Lines Using LED

Methylene blue (MB) has been used in clinical medicine for many years and has been accepted as a drug for photodynamic therapy (PDT). In this study, the therapeutic effect of MB in HT-29 colon cancer cells was investigated in vitro. In recent years, LEDs (light-emitting diodes) have been used as a light source in FDT. However, there are not many studies examining the effect of FDT in combination with LEDs. Therefore, in this study, antitumor effect of MB mediated PDT was evaluated by using 635nm LED light source to colon cancer cells. Colon cancer cells were planted in a petri dish and MB was added. 16mW/cm² power density and 3J/cm² energy lavel with 635nm LED were applied to 2s, 6h, 16h, 24h, 48h, 72h after the cells were added to the medium. After 72 hours, significant antitumor effects were observed when MB mediated FDT was used with LED light source. 80% of cell death occurred.