AN EQUIBIAXIAL STRAIN SYSTEM FOR CULTURED-CELLS

We developed a device that applies homogeneous equibiaxial strains of 0-10% to a cell culture substrate and quantitatively verified transmis sion of substrate deformation to cultured cardiac cells. Clamped elast ic membranes in both single-well and multiwell versions of the device are uniformly stretched by indentation with a plastic ring, resulting in strain that is directly proportional to the pitch-to-radius ratio. Two-dimensional deformations were measured by tracking fluorescent mic rospheres attached to the substrate and to cultured adult rat cardiac fibroblasts. For nominal stretches up to 18%, strains along circumfere ntial and radial axes were equal in magnitude and homogeneously distri buted with negligible shear. For 5% stretch, circumferential and radia l strains in the substrate were 0.046 +/- 0.005 and 0.048 +/- 0.004 [n ot significant (NS)], respectively, and shear strain was 0.001 +/- 0.0 03 (NS). Calibration of both single-well and multiwell versions permit s strain selection by device rotation. The reproducible application an d quantification of homogeneous equibiaxial strain in cultured cells p rovides a quantitative approach for correlating mechanical stimuli to cellular transduction mechanisms.