Reaction-based small-molecule fluorescent probes for chemoselective bioimaging

The complexity of living systems makes attempts to gain a molecular-level understanding of them a unique and inspiring challenge. This Review summarizes progress in the development of bioorthogonal reaction-based fluorescent probes used to follow the spatial and temporal dynamics of biologically important analytes within living systems. The dynamic chemical diversity of elements, ions and molecules that form the basis of life offers both a challenge and an opportunity for study. Small-molecule fluorescent probes can make use of selective, bioorthogonal chemistries to report on specific analytes in cells and in more complex biological specimens. These probes offer powerful reagents to interrogate the physiology and pathology of reactive chemical species in their native environments with minimal perturbation to living systems. This Review presents a survey of tools and tactics for using such probes to detect biologically important chemical analytes. We highlight design criteria for effective chemical tools for use in biological applications as well as gaps for future exploration.