Photodynamic therapy (PDT) is an effective therapeutic modality that uses a light source to activate light-sensitive photosensitizers to treat both oncologic and nononcological indications. Photosensitizers are excited to the long-lived triplet state, and they react with biomolecules via type I or II mechanism resulted in cell death and tumor necrosis. Free radicals and radical ions are formed by electron transfer reactions (type I), which rapidly react with oxygen leading to the production of reactive oxygen species (ROS), including superoxide ions, hydroxyl radicals and hydrogen peroxide. Singlet molecular oxygen is produced in a Type II reaction, in which the excited singlet state of the photosensitizer generated upon photon absorption by the ground-state photosensitizer molecule undergoes intersystem crossing to a long-lived triplet state. In this talk, the fundmental mechanisms and detection techniques for ROS generation in PDT will be introduced. In particular, the quantification of singlet oxygen generation for pre-clinical application will be highlighted, which plays an essential role in the establishment of robust singlet oxygen-mediated PDT dosimetry.

Date Published: 31 October 2016
PDF: 5 pages
Proc. SPIE 10024, Optics in Health Care and Biomedical Optics VII, 100241C (31 October 2016); doi: 10.1117/12.2246526

Published in SPIE Proceedings Vol. 10024:
Optics in Health Care and Biomedical Optics VII
Qingming Luo; Xingde Li; Ying Gu; Yuguo Tang, Editor(s)