Applications of combined spectral lifetime microscopy for biology.

Live cell imaging has been greatly advanced by the recent development of new fluorescence microscopy-based methods such as multiphoton laser-scanning microscopy, which can noninvasively image deep into live specimens and generate images of extrinsic and intrinsic signals. Of recent interest has been the development of techniques that can harness properties of fluorescence, other than intensity, such as the emission spectrum and excited state lifetime of a fluorophore. Spectra can be used to discriminate between fluorophores, and lifetime can be used to report on the microenvironment of fluorophores. We describe a novel technique-combined spectral and lifetime imaging-which combines the benefits of multiphoton microscopy, spectral discrimination, and lifetime analysis and allows for the simultaneous collection of all three dimensions of data along with spatial and temporal information.