Targeted Delivery of Carbon Monoxide

Carbon monoxide (CO) is widely known for its strong binding affinity to heme proteins and for its potential toxicity. This chapter examines the current landscape of targeted CO delivery using CO donors, including metal-based CORMs, organic CO prodrugs, and others that are sensitive to various stimuli. As a framework to consider targeted CO delivery, it starts with a summary of the endogenous production of CO by heme oxygenase enzymes, focusing on the subcellular and tissue localization of these enzymes. Subsequently described are the structural motifs associated with well-known molecular CO donors that have been used extensively in biological applications as well as emerging structural motifs that offer enhanced control for targeted CO delivery. Nanomaterial-based approaches for the delivery of gasotransmitters, including CO, are a very active field of research, with several recent reviews highlighting advancements in this area. Upconverting nanoparticles offer the possibility of using NIR illumination to trigger CO release in metal carbonyl complexes.