The biophysical aspects of photodynamic therapy

Abstract

The photodynamic effect, viz., photodamage of stained cells in the presence of oxygen, is used for destruction of tumors and other abnormal cells. The present review considers the biophysical mechanisms of the photodynamic action on cells. The importance of two major mechanisms of photodynamic damage of cells is discussed. The first one is mediated by electron or proton transfer, whereas the second one involves singlet oxygen. Another question that is considered is the importance of oxidation of membrane lipids or proteins for the photodynamic damage of cells. The phototransformation of photosensitizers and their intracellular localization and delivery to cells and tissues that have undergone abnormal changes are discussed. The current data on photosensitizer nanotransporters are presented. The potential sensors for reactive oxygen species in cells are discussed.