Effect of Tissue Optical Properties on the Fluorescence of BODIPY Derivative as a Photosensitizer for Photodynamic Therapy

Abstract

Photodynamic therapy is widely used as an established biomedical optical modality for the conservative treatment of tumors. This work investigates laser-induced fluorescence spectroscopy of the emerging photodynamic photosensitizer BODIPY-520 in turbid media. A 520 nm laser diode was used for exciting tissue-like optical phantoms. Effects of scattering and absorption of the turbid medium on the recorded fluoresced signal were studied. The results show that the BODIPY-520 photosensitizer has a prominent fluorescence peak at 600 nm, and that the optical properties of the surrounding turbid medium influence the spectral characteristics of fluorescence signals. The experimental work reveals that the characteristic fluorescence intensity peak of BODIPY-520 photosensitizer positioned at 600 nm is red-shifted to 675 nm in the presence of absorbing component, and with no red-shift in the presence of scattering components in the optical phantom under investigation. The effect of oxygen concentration on the detected fluorescence spectra is also quantified. The findings obtained from this study can be incorporated into an optimized protocol for BODIPY-520 based photodynamic therapy.