ISSN:
1573-4994
Keywords:
Fluorescence lifetime imaging microscopy
;
intracellular calcium
;
live cells
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract Fluorescence lifetime imaging microscopy (FLIM) is a new methodology for studying the spatial and temporal dynamics of macromolecule, molecules, and ions in living cells. In FLIM image contrast is derived from the mean fluorescence lifetime at each point in a two-dimensional image. In our case the lifetime was measured by the phase-modulation method. We describe our FLIM apparatus, which consists of a fluorescence microscope, high-speed gated proximity focused MCP image intensifier, and slow-scan CCD camera. To accomplish subnanosecond time-resolved imaging, the gain of the image intensifier is modulated with a high-frequency signal, resulting in stationary phase-sensitive intensity images on the image intensifier. These images are recorded using a cooled slow-scan CCD camera and stored in an image processor. The lifetime images are created from a series of phase-sensitive images at various phase shift of the gain-modulation signal. We demonstrate calcium concentration imaging in living COS cells based on Ca2+-induced lifetime changes of Quin-2. The phase-angle image is mapped to the Ca2+ concentration image using anin vitro-determined calibration curve. The Ca2+ concentration was found to be uniform throughout the cell. In contrast, the intensity image shows significant spatial differences, which likely reflect variations in the thickness and distribution of probe within the cell.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00862736
Permalink
