Photodynamic therapy: physical, biochemical and clinical aspects

Abstract

Photodynamic therapy (PDT) is a therapy in which a combination of visible light, drugs that are photoactivated and oxygen, is used to destroy tissues diseased by cancer and other pathological conditions that have abnormal cellular growth as common characteristic. Good results of a PDT treatment depend on a series of processes dealing with the interaction between light and living tissues and involve knowledge of several disciplines including physics/photonics chemistry/biochemistry and biology/medicine. These processes will be treated together in this project by an interdisciplinary team of researchers. Our main goals are: 1) to understand the physical, chemical, biochemical and medical mechanisms determining the efficiency of a PDT treatment; 2) to synthesize, characterize, apply for patents and publicize new potential drugs for use in PDT; 3) to propose new and inexpensive clinical protocols in PDT; 4) to make PDT known to the professionals working in health sciences, as well as to the general population. To reach these goals the group plans to develop five sub-projects: a) physical aspects that affect the PDT efficiency: light penetration in the living tissues and photosensibilizer activation; b) mechanisms in PDT: interaction of photoinduced reactive species with biological systems; c) in vivo PDT and clinical tests; d) synthesis of new photoactive molecules and nanomaterials; e) interaction of biologically relevant systems with membranes and interfaces. The central part of this project is focused on the physical, chemical and biochemical aspects of PDT, generating novel mechanistic knowledge. New photo-pharmaceuticals will be designed and synthesized based on this knowledge. These drugs will be characterized in their physical-structural aspects (size, shape, aggregation, magnetization) by the group of physicists, and in their chemical and biochemical aspects by a group of members of IQ-USP. The therapeutic evaluation will be performed in the ABC School of Medicine. (AU)