TCSPC / Fluorescence Lifetime Imaging Microscopy (FLIM)

Fluorescence microscopy is an established method of precisely analyzing sample composition, but fluorescence alone cannot necessarily tell the researcher about molecular mobility, binding interactions, or size; therefore, knowing the interval a molecule takes to become excited, fluoresce, and return to its ground state leads to insight into factors affecting mobility and molecular environment. Fluorescence lifetime imaging microscopy (or FLIM) measures the onset and lifetime of the fluorophore signal. Using time-correlated single photon counting (TCSPC), lifetime measurements with the precision of 100 picoseconds or less can be studied in detail, and the temporal contour of the fluorescence is measured in real time. A FLIM microscope can employ a range of wavelengths from the UV to near IR. Confocal microscopy capabilities permit 3D reconstruction of imaged biological and chemical samples, as well as the ability to image distinct layers in the Z axis to the exclusion of others. Because of the precision required for tasks involving FLIM microscopy, some models are fully motorized.