Medical Uses of Fluorescence Imaging: Bringing Disease to Light

Fluorescence imaging is becoming an important diagnostic method in medicine. Advances in the quantum yields and properties of fluorophores combined with better biologic targeting make fluorescence imaging attractive. The lack of ionizing radiation, the lower costs, and the portability of optical imaging are additional advantages. Traditional fluorescence imaging probes are “always on” and require rapid biologic clearance of the unbound probe to achieve adequate target-to-background ratios. More advanced fluorescence imaging probes are “activatable,” meaning that they become fluorescent only under particular circumstances, such as after binding to the cell. This creates opportunities for very high target-to-background ratios, thus dramatically increasing sensitivity. When fluorescent probes also cause phototoxicity, they become both therapeutic and diagnostic (theranostic) agents and enable a “see and treat” paradigms. Here, we discuss the evolution of novel diagnostic probes in our laboratory ending with the development of targeted theranostic probes.