Abstract
We numerically investigate the velocity of an adherent cell in various sizes of microchannels. The velocity drastically decreases as decreasing the size of microchannels. When the channel size becomes smaller, the motion of the adherent cell changes from a "rolling motion" to a "bullet motion", where the cell rotates on side wall in rolling motion, while the cell adhere its circular arc to the wall in bullet motion. Larger adhesion force is generated in rear parts of rolling cell, and existed bonds experience rupturing with higher probability because of slip bond. Because cell cannot move forward unless the ligand-receptor bonds in rear parts rupture, frequent rupturing allows the rolling cell to move faster than the cell exhibiting bullet motion. As getting smaller in channel diameter, the surface area attached to the wall is larger and then the number of ligand-receptor bonds is larger for smaller microchannels, resulting in a lower velocity. Our numerical model allows us to investigate the effect of various parameters on adherent cell velocity.
