Bone targeted photodynamic therapy

Abstract

Photodynamic therapy (PDT) is a method for treatment of cancerous tumors and many other diseases. PDT is the preferential delivery of a photosensitizer (PS) to tumor tissue which is followed by irradiation of light of specific wavelength. After irradiation, the generation of reactive singlet oxygen (ROS) species on tumor, where photosensitizer has been localized specifically, results in cell death due to interaction of ROS with vital cellular components. Bone targeting is an alternative to apply in photodynamic therapy. No BP-based targeting has been designed for photodynamic therapy at bones to date. BP-mediated PS targeting improves therapeutic effects on bone tissue by concentrating PS at bones. In this work, PEG based copolymers containing a potosensitizer and a targeting group was prepared to accomplish bone targeting in photodynamic therapy. As a carrier, a biocompatible polymer was chosen primarily because of its ease of processing and the ability to control the chemical and physical behaviour.