Macroscopic Friction Coefficient Measurements on Living Endothelial Cells

Arterial stent deployment by balloon or selfexpandable structure introduces shear forces and radial forces that can damage or remove the endothelial cell layer. These factors can subsequently cause failure by restenosis or endothelial leaks. These conditions can be exacerbated by pulsatile blood flow and arterial asymmetry, which can cause migration or displacement. In mechanical or finiteelement models which attempt to explain this motion, friction between the stent materials and endothelial cells is eclipsed by pressure, or assumptions that cells are moved along with the stent. During device deployment or migration, some relative motion between stent materials and endothelial cells occurs. This study aims to quantify friction between a polished glass pin and a single layer of arterial endothelial cells, and include observations of cell damage in an attempt to better understand the biological response to tribological stresses. Measured friction coefficient values were on the order of l = 0.03–0.06.