Spiropyran Derivatives as a Photosensitizer for Photoswitchable ROS Generation

Abstract

Reversibly controlled generation of singlet oxygen from photosensitizing materials benefits in selective cell killing and controllable effect time, but is a challenging option for photodynamic therapies. A series of new spiropyrans of indoline series with N-alkylation has been synthesized, their structure and photochromic properties have been studied. The structure of the obtained compounds was confirmed by the data of 1H, 13C NMR, IR spectroscopy, and elemental analysis. Photochromic properties of the prepared compounds have been studied. We found spiropyran derivatives have photoswitching properties in both fluorescence and singlet oxygen generation in aqueous solutions and cells, and demonstrated N-alkylated spiropyrans enhanced photosensitization and emission could be potentially applied for photodynamic therapy studies on tumor cells.