In-vitro investigation of cold atmospheric plasma induced photodynamic effect by Indocyanine green and Protoporphyrin IX

Background: Photodynamic therapy (PDT) is one of the non-invasive methods for the treatment of superficial malignant cancers. One of the limiting challenges of PDT is the hypoxic conditions during treatment that reduces PDT Efficiency. Because of ROS and free radicals in plasma flame output, Cold atmospheric plasma (CAP) may improve treatment efficiency. In this study, the effect of plasma-induced photodynamic effect of two Photosensitizers (PSs) include Indocyanine green (ICG) and Protoporphyrin IX (PPIX) on two cell lines (MCF-7 and HT-29) was investigated. Methods: First, toxicity of different concentrations of PSs (5-50 mu M) were examined on cell lines. After that, we surveyed low toxicity of PSs concentrations with different plasma radiation doses. To quantitative of cell survival, MIT assay was performed after 48 h. Finally, in order to statistical analysis of data, we used SPSS software (version 20) and also in order to better comparison the results, we used indexes such as Plasma sensitivity index and Synergism index. Results: The results indicate that in most irradiant conditions; for ICG + CAP group, PSI > 1 and SI < 1 in the both of cell line (P < 0.05). Also for PPIX + CAP group in most irradiant conditions, only in the HT-29 cell line can it be said with certainty that both indexes (PSI and SI) are higher than 1 (P < 0 - 05). Conclusion: The results show that the plasma-induced photodynamic therapy with ICG and PPIX has more effective results on MCF-7 (breast cancer) and HT-29 (colon cancer) cell line, respectively. Also, the synergistic effect was observed only for PPIX in the HT-29 cell line.