Mechanistic insight into photoactivation of small inorganic molecules from the biomedical applications perspectives

Abstract

Photogeneration of reactive small inorganic molecules (RSIM) by molecular and nanostructured systems with an emphasis on the mechanisms involved in the process are reviewed. RSIM, including reactive oxygen species (ROS), nitrogen species (RNS), sulfur species (RSS), chlorine species (RClS), and carbon species (RCS), play a pivotal role in physiological and pathological processes. Photodissociation, photoisomerization, photosubstitution, or photoredox reactions of RSIM precursors constituted pathways of their direct generation and have been studied mostly in molecular systems, whereas research interest in photosensitized RSIM generation processes is focused on both molecular and nanostructured systems. In vivo light management strategies and mechanisms of light-stimulated processes leading to spatially and temporally controlled RSIM generation such as optogenetics, photocleavage, photosensitization, and homogeneous and heterogeneous photocatalysis are discussed, and representative examples are presented. A variety of photoactive molecular, macromolecular, nanostructured, and hybrid materials are discussed considering their RSIM photogeneration properties and potent biological and medical applications.