Rapid, multipoint molecular spectroscopic measurements of shear effects on endothelial cell membranes

Endothelial cells (ECs) form the inner lining; of the blood vasculature and are therefore exposed to shear stress (tau), the tangential component of hemodynamic forces. Shear stress exacts potent changes in EC biology, possibly via EC-membrane perturbations, with consequent influences on vascular health. We describe a time-correlated single photon counting method for measuring rapid and spatially heterogeneous changes in fluorescence lifetimes and polarizations of EC membranes exposed to shear stress. The role in mechanotransduction by ECs of shear-induced changes in membrane lipid dynamics is discussed.