New views inside cells with a digital imaging microscope

Abstract

Many current questions in cell biology revolve around questions regarding how changes in cell function are caused by changes in their molecular composition. Given that cells are highly organized structures often carrying out diverse functions in different compartments, it follows that changes in specific cell functions must involve highly localized changes in molecular composition.We have been involved in the development of the digital imaging microscope as a tool to investigate the distribution of molecules inside single living cells. The system measures fluorescence of probes that are highly fluorescent and specific for a molecule or ion of interest and utilizes a wide-field rather than a confocal microscope to produce an image of fluorescence in a single cell. The image is captured by a high quantum efficiency, low noise cooled CCD, thereby providing ultrahigh efficiency in the acquisition of fluorescent images. By utilizing very powerful light sources, the system is capable of generating an image with good signal-to-noise ratio in a millisecond or less, thereby allowing one to follow extremely rapid changes in molecular or ion distribution in single cells.