Time-resolved fluorescence microscopy of stressed membranes of living endothelial cells

Advances in the understanding of mechanotransduction in endothelial cells require reliable predictive models of stress and readouts of mechano-activation in the same cell. In order to determine correlations between stress and cellular activation, we have coupled rapid 3-D rendering of optical images of stained endothelial cells and computational fluid and mechanics models with photonics-based detection of molecular perturbation. Central to our approach is a multimodal, confocal molecular dynamics microscope with time-correlated, single-photon counting electronics to measure excited-state lifetime dynamics of fluorescent molecules in cell membranes. Preliminary results suggest a correlation of positive shear stress gradients and membrane tension with shear-induced membrane perturbations at sub-micron scales. Such position-dependence of membrane stress concentrations may be used as cues for mechano-chemical signal transduction.