Cell Behavior During Accelerated Passing Through Micro-Gap

A biological cell is flexible and must deform to pass through a narrow gap. Therefore, in capillaries and in liver and spleen sinusoids, vascular constrictions plays the role of a filter to sort healthy from damaged cells <em>in vivo</em>. In this study, deformation of a cell during accelerated passage through a microgap in a microflow channel was analyzed <em>in vitro</em>. A gap with the rectangular cross section (7 μm height, 0.8 mm width, and 0.1 mm length) was inserted at the middle of a microflow channel using photolithography. Myoblasts (C2C12: mouse myoblast cells) were used in the test. The flow rate of the medium fluid, in which cells were suspended, was controlled by the pressure head between the inlet and outlet. The deformation of smaller cells passing through the microgap with an accelerated velocity was observed with an inverted phase-contrast microscope. The results show that each elongated smalller (diameter < 15 μm) cell tends to tilt parallel to the flow direction during its transit through the gap.