Selective Response of Cancer and Normal Cells to 808 nm near Infrared Low Level Laser Irradiation: An in Vitro Study

Introduction: This study aims to investigate laser irradiation therapy as a potential non-invasive treatment for breast cancer, introducing a promising alternative with the potential for the selective inhibition of cancerous cells while minimizing damage to surrounding healthy tissues. Methods: In this study, the utilization of cell culture stands out as an excellent methodology for evaluating both the effects and dosage of a given treatment. This study was conducted to evaluate the selective effect of low-level near-infrared (NIR) laser at an 808 nm wavelength, along with single and double irradiation with 5-minute intervals, on human breast cancer (MDA-MB-231) cells and human foreskin fibroblasts (Hs-27) cells using different laser powers and exposure times. The experiment involved exposing both cell lines to an NIR laser at 25, 43, 120, and 300 mW for 1, 5, 10, and 15 minutes. Cell viability was assessed via the MTT assay. Results: The outcomes revealed disparate responses in both cell types used in this study. The double irradiation procedure with a 15-minute exposure at 25, 43, 120, and 300 mW displayed the most inhibition of cancer cell growth among the applied durations. Notably, using 300 mW during 15-minute double irradiation resulted in the highest cancer cell growth inhibition at 4.67%. Conversely, normal cells showed enhanced proliferation across most powers and exposure times applied. However, a considerable reduction in the cell viability of normal cells was evident following 15-minute double irradiation at 300 mW. This indicates that normal cells have been negatively affected by this power. Caution is advised. Conclusion: The results suggest that NIR laser therapy at 808 nm with different output powers and exposure times significantly inhibits MDA-MB-231 cells, and this approach exhibits promising potential for inducing cancer cell death.