Development of cancer theraphy with ICG-PDT supported by gold nanoparticles

Photodynamic therapy (PDT) is an application based on the killing of unwanted cells with photochemical reactions based on photosensitizer induced by light at an appropriate wavelength and the use of oxygen in the environment. Spherical gold nanoparticles (AuNPs) have been interesting because of their easy synthesis and easy functionalization thanks to their conjugation properties. The aim of this study is to investigate the efficacy of PDT on cancer cells with an 809-nm laser, which has higher optical penetration to biological tissues than other lasers using the indocyanine green (ICG) as a photosensitizer loaded onto a gold nanoscale carrier. For this purpose, PDT was applied to the cells of the prostate (PC-3) and colon (Caco-2) cancer and the results were compared with control groups and each other. Cell viability was monitored by MTT test to measure the efficacy of the dose of AuNP-ICG used during these experiments. On Caco-2 and PC-3 cell lines, 25 μM, 50 μM and 100 μM ICG concentrations and 25, 50 and 100 J/cm2 laser power density groups were compared. As a result of these studies, it was found that the AuNP-ICG had a toxic effect on treated cell lines. It was also observed that colon cancer cells were more resistant to PDT with AuNP-ICG than prostate cancer cells. Although there was no significant decrease in cell viability without toxic effect in PC-3 cells, they showed a significant viability decrease compared to the control group. In Caco-2 cells, this significant decrease was observed at higher dosages and higher energy density.