Development of a Cell Micro Tensile Tester and Its Application to Quantitative Analysis of Cell Stiffness and Adhesion Forces of Vascular Smooth Muscle Cells

Abstract

Vascular walls change their dimensions and mechanical properties in pathological condition under hormonal and biomechanical stimuli, and such changes are generated by smooth muscle cells in the vascular tissues. Thus cellular mechanical properties are quite important for understanding the mechanism of vascular disease. Recent researches demonstrated the measurement of surface local mechanical properties of a single cell level using micro engineering technology, such as an atomic force microscopy and optical tweezers. However, it is unclear the mechanical properties of cells in a wide rage of strain and cell-substrate adhesion strength which is quite important for the muscle cell mechanics in tissue. Here we developed a novel cell micro tensile tester, and investigated the tensile stiffness and adhesion strength of vascular smooth muscle cells. We assessed the correlation between whole cell stiffness, adhesion strength, and the cell spreading area. The cell adhesion strength has a positive correlation with cell spreading area. On the other hand, cell tensile stiffness was almost constant even though morphological dimensions of cells were quite varied. These results indicate that vascular smooth muscle cells keep their tensile stiffness constant to sustain vascular wall strength. Our micro tensile tester should be a powerful tool in investigating cellular mechanical functions.