Chemigenetic Approaches for the Development of Fluorescent Biosensors for Biological Imaging

Fluorescent biosensors are essential for probing analyte dynamics and enzyme activities with high spatial and temporal resolution in living cells by functional microscopy. Recently hybrid, or so called chemigenetic, biosensors have emerged, that integrate the strengths of synthetic fluorophores - such as spectral diversity, high brightness and photostability - with the specificity and sensitivity of genetically encoded sensing units. Beyond enhancing optical performance, synthetic chemistry can also expand the repertoire of sensing units themselves, creating opportunities for novel biosensor designs sensing previously inaccessible analytes. In this review, we summarize the protein-labeling strategies used in chemigenetic biosensor design with particular emphasis on self-labeling protein tags. We further discuss biosensor design principles, representative applications, and emerging advances that highlight the growing impact of chemigenetic biosensors in functional microscopy.