Photodynamic therapy(PDT) is a cancer therapeutic modality that utilizes photosensitizers(PSs) and molecular oxygen upon irradiation with light to generate cytotoxic reactive oxygen species leading to damage of the target tissues and cells. Activatable photosensitizers(aPSs)that are inactivated initially, can only be activated by tumor-associated stimuli, such as tumor-associated specific enzymes, acidic pH, nucleic acid, to achieve targeting diagnosis and treatment. The aPSs have become a hot spot in the field of medical photosensitizers because of its higher selectivity. In this paper, we will summarize the recent development of aPSs, and analyze their structure-activity relationships, expecting to provide a reference for the future studies.
Contents
1 Introduction
2 pH-activatable photosensitizers
3 Enzyme-activatable photosensitizers
3.1 Cathepsin-activatable photosensitizers
3.2 Urokinase type plasminogenactivator(uPA)-activatable photosensitizers
3.3 Fibroblast activation protein-α(FAPα)-activatable photosensitizers
3.4 Matrix metalloproteinase(MMP)-activatable photosensitizers
3.5 Hyaluronidase-activatable photosensitizers
3.6 Other enzyme-activatable photosensitizers
4 Nucleic acid-activatable photosensitizers
5 Other activatable photosensitizers
6 Perspective