Anisotropic, Three-Dimensional Deformation of Single Attached Cells under Compression

Abstract—Quantifying three-dimensional deformation of cells under mechanical load is relevant when studying cell deforma-tion in relation to cellular functioning. Because most cells are anchorage dependent for normal functioning, it is desired to study cells in their attached configuration. This study reports new three-dimensional morphometric measurements of cell deformation dur-ing stepwise compression experiments with a recently developed cell loading device. The device allows global, unconfined com-pression of individual, attached cells under optimal environmen-tal conditions. Three-dimensional images of fluorescently stained myoblasts were recorded with confocal microscopy and analyzed with image restoration and three-dimensional image reconstruc-tion software to quantify cell deformation. In response to compres-sion, cell width, cross-sectional area, and surface area increased significantly with applied strain, whereas cell volume remained constant. Interestingly, the cell and the nucleus deformed perpen-dicular to the direction of actin filaments present along the long axis of the cell. This strongly suggests that this anisotropic defor-mation can be attributed to the preferred orientation of actin fila-ments. A shape factor was introduced to quantify the global shape of attached cells. The increase of this factor during compression reflected the anisotropic deformation of the cell. Keywords—Cell mechanics, Image analysis, Cell deformation, Muscle cell, Confocal microscopy