Time Correlated Single Photon Counting:  Measuring Fluorescence Lifetime and diffusion of membrane dyes.

Forces induce coordinated biochemical signaling cascades in cells over a wide range of spatial and temporal scales.   We have developed new integrated tools based on multimodal microscopy and single photon counting to elucidate the molecular basis of mechanotransduction over large temporal ranges in cells subjected to well-defined forces.  Total internal reflection, epi-fluorescence, differential interference contrast, and 3-D deconvolution provide the means to correlate the single molecule spectroscopic measurements from fluorescence correlation spectroscopy (FCS) and time- resolved fluorescence with precise spatial locations in the cell.  With this new hybrid microscopy system, precise effects of force on single molecule dynamics can be mapped spatially in response well-defined forces imposed by micropipette aspiration, optically trapped beads, and fluid flow.

For more information, please see our recent publication in the Journal of Biomedical Optics