Laser diode coupled with optical fiber for applications in photodynamic therapy

A diode laser with roughly 480 mW/cm2 emission at 776 nm was developed and engineered to obtain a uniform illumination of tumour cells deposited on Petri dishes having an external diameter of 5 cm. The efficacy of the apparatus in inducing photocytotoxic effects was successfully checked by irradiation of pigmented melanoma cells in the presence of a photosensitizer, Si(IV)-naphthalocyanine, having intense absorption bands at 776 nm. Our results open interesting prospects for extending photodynamic therapy to highly pigmented tumours.