Fluorescence Lifetime Imaging (FLIM)

Fluorescence-lifetime imaging microscopy (FLIM) is an imaging technique for producing an image based on differences in the fluorescence-lifetime rather than its intensity. By quantifying variations in the exponential decay rate of the fluorescence from a fluorescent sample (fluorescence-lifetime) it is possible to report on molecule proximity, pH changes and even polarity. It can be used as an imaging technique in confocal microscopy, two-photon excitation microscopy and multiphoton tomography. Since the fluorescence-lifetime is insensitive to changes in fluorophore intensity or concentration, it is the most quantitatively precise technique to report on fluoresce resonance energy transfer (FRET).