Development of a Biaxial Cyclic Stretching Mechanism and Its Use for the Analysis of Mechanical Response of Vascular Endothelial Cells

Abstract

Study on the cellular responses to biaxial cyclic stretch requires a complex device giving two dimensional deformations to cell substrates. To carry out the biaxial testing easily, we have developed a mechanism that makes a conventional uniaxial device to biaxial one. By incorporating two three-bar linkages into a conventional uniaxial device NS-300, we obtained cyclic stretching motion perpendicular to its original stretch direction. Difference in the displacement between the two directions was less than 1.4% for a 10% stretching mode. By changing the linkage assembly, we can select two modes of biaxial stretching : simultaneous and alternate. The deformation of the silicone membrane on the bottom of a newly developed biaxial chamber was almost uniform in the central region of 12mm×12mm. We applied various modes of biaxial and uniaxial cyclic stretches to bovine aortic endothelial cells with this device, and found that the cells aligned in the direction with minimal substrate deformation, a well-known cellular response to cyclic stretch. This device is useful in studying cellular response to biaxial stretching for its easiness in extending capability of conventional uniaxial stretch devices to biaxial ones.