Revealing the therapeutic effects of aminolevulinate mediated femtosecond laser induced photo-chemotherapy in different cancer cells

Abstract Photodynamic therapy (PDT) is a photo chemotherapeutic strategy that is the application of photosensitizing agent and light on disease or tumor site. The aim of this study is to confirm the feasibility for femtosecond (fs) laser for aminolevulinate (ALA) mediated PDT on skin, breast and bladder cancer cells. Also the remarkable aspects of ALA mediated and laser induced PDT with respect to other literally known applications were investigated. Metastatic melanoma cells SK-MEL30, mammary epithelial carcinoma cells MCF-7 and bladder cancer cells UMUC-3 were treated with ALA and then the cells were irradiated by fs laser at thirty wavelengths in between 230 and 800 nm for 30s and 60s. Anti-cancer effects of ALA phototherapy on different cancer cell lines were determined. Protoporphyrin IX (PpIX) accumulation was visualized by confocal microscopy. The effective PDT wavelengths were applied to evaluate the degree of apoptosis and necrosis in cells. The viability tests demonstrated that wavelengths 400-440 nm and 600-630 nm were found to decrease the viability on three model cell lines. PDT at 630 nm exerted cell death by necrosis and apoptosis after 30 s and 60 s periods. This paper confirms that ALA and femtosecond laser mediated PDT may be used together as therapeutic and diagnostic method to target breast, skin and urinary bladder cancer cells. The use of fs laser allows the flexibility for optimization of wavelength for photosensitizing agents.