Fluorescence-lifetime imaging with a multifocal two-photon microscope.

Two-photon microscopy is a powerful tool for imaging of cells or tissues. However, it presents the drawback of being a laser-scanning technique that involves a long acquisition time for fluorescence-lifetime imaging. Thus it is commonly limited to intensity images that give only indications of the location of fluorophores but do not identify the physicochemical properties and interactions between cells' components. To protect biological samples from experiments that are too long and to provide a more comprehensive spectroscopic tool we have developed a time-resolved multifocal multiphoton microscope. This setup allows us to speed up the acquisition while retaining the possibility of measuring both intensity and lifetime images of the sample.