Shigehiro Hashimoto
Abstract
An erythrocyte has high deformability. In the shear field, it deforms from biconcave disc to ellipsoid, and make tank-treading motion at the membrane. When the membrane is ruptured by fatigue, contents get out from the inside of the cell (hemolysis). At the fatigue test of the membrane in the shear field, ...
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An erythrocyte has high deformability. In the shear field, it deforms from biconcave disc to ellipsoid, and make tank-treading motion at the membrane. When the membrane is ruptured by fatigue, contents get out from the inside of the cell (hemolysis). At the fatigue test of the membrane in the shear field, “the shear stress” as “the amplitude” and “the shear rate” × “the exposure time” as “repeat count” are critical parameters. For the quantitative fatigue test, the uniform shear field has been realized between the rotating concave cone and the stationary convex cone. With the rheoscope, deformability is evaluated with shear stress responsiveness and with critical deformation calculated from an exponential curve between the deformation ratio (the ratio between the major axis and the minor axis of the ellipsoidal shape) and the shear stress. Deformability decreases at erythrocytes of high density after shearing. The erythrocytes deformation ratio varies periodically at the double frequency of tank-treading motion of the membrane, when the erythrocyte has the sublethal damage point on the membrane.

Shigehiro Hashimoto
Abstract
Biological cells adsorb on the scaffold, and show activities: migration, deformation, proliferation, and differentiation. The micro morphology (close to the cell size) on the surface of the scaffold (made by the photolithography technique) is effective for several applications: the marker to trace each ...
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Biological cells adsorb on the scaffold, and show activities: migration, deformation, proliferation, and differentiation. The micro morphology (close to the cell size) on the surface of the scaffold (made by the photolithography technique) is effective for several applications: the marker to trace each cell, and the tool to control the activity of each cell. C2C12 (mouse myoblast) is used in the present study. The typical diameter of the cell is 20 μm, when it is suspended in the medium. The cell aligns along the micro step of the height (> 0.7 μm). The micro-striped groove can control the cell orientation in the flow channel. The aspect ratio of the checkered convexo-concave pattern can control the orientation of cells. When cells are cultured on the thin film (thickness 6 μm, polydimethylsiloxane) with the micro markers at the counter surface, the local contraction movement of myotubes by the electrical-pulse stimulation can be microscopically measured through the transparent scaffold.
