Fluorescence-lifetime technologies for high-throughput screening

Fluorescence lifetime, the mean interval between absorption and emission, is as fundamental a characteristic of fluorescence as excitation and emission wavelengths and quantum yield. Yet, with the exception of time-resolved fluorescence assays utilizing lanthanide chelates, the analytical possibilities of methods based on fluorescence lifetime are virtually unexploited outside the academic research laboratory. We discuss the potential use of fluorescence-lifetime technologies in high-throughput screening from the standpoint of assay reagents and instrumentation. Among these applications are fluorescence- polarization assays based on long-lifetime probes and fluorescence-intensity assays using lifetime-resolved detection to reject background. We find that fluorescence- lifetime technologies offer significant practical advantages over existing methods.