Force measurements on platelet surfaces with high spatial resolution under physiological conditions.

Investigations on platelets are essential to understanding the regulation of hemostasis and thrombosis. Activated platelets undergo dramatic conformational and morphological changes mediated by numerous plasma proteins. AFM techniques can combine high spatial resolution with measurements of the mechanical properties of platelet surfaces. Here, we demonstrate two-dimensional force mapping over a human platelet adsorbed on glass under physiological buffer. The best resolution of platelet membrane elasticity we obtained was at 15.6x15.6 nm(2) pixel(-1). In addition, quantitative information on platelet surface charge density was extracted from individual force curves with the aid of DLVO theory.