Discussion

Fluorescence lifetime of fluorophores varies in response to their immediate molecular surrounding. It changes with physico-chemical environment properties (Ca2+, pH, viscosity) or with biomolecular associations and conformation changes by virtue of Förster resonant energy transfer (FRET). In life sciences, fluorescence lifetime is typically measured by imaging methods with throughput often limited to a few cells per minute. We introduce MicroFLiC, a flow cytometer quantifying fluorescence lifetime on cell-by-cell basis achieving a throughput of 3000 of cells per minute.