Fluorescence lifetime and polarization-resolved imaging in cell biology

Fluorescence lifetime imaging (FLIM) and fluorescence polarization imaging are complementary techniques that can be used to extract information about macromolecules from biological samples. Owing to the sensitivity of fluorescence to the physicochemical environment, and nanometer-scale interactions via Förster resonance energy transfer (FRET), FLIM has been implemented in many laboratories for numerous applications in the life sciences and beyond. This review seeks to provide a brief overview of some of the recent advances in the techniques and more pertinently their applications in cell and tissue imaging. The particular merits of polarization-resolved fluorescence measurements are highlighted, including the unique ability to elucidate the occurrence of homo-FRET.