Fig. 3.
(a) Cell-surface gap estimate based on matching simulated gap-size dependent hydrodynamic velocity (solid lines) with average cell velocity measured under various flow rates (dash lines); the average free-motion velocity was measured for MDA-MB-231 cells passing through anti-N-cadherin functionalized microchannels with negligible receptor-ligand interaction, and (b) Spring constant estimate based on matching calculated spring-constant dependent cell velocity with measured cell velocity during capture; the firm-adhesion velocity was measured for MDA-MB-231 cells captured in anti-EpCAM functionalized microchannels under a flow rate of 0.9μl/min. The cell-surface gap is estimated to be about h=490nm, independent of the applied flow rate, while the spring constant is estimated to be about K=850nN/m assuming D=0.05μm and NR=1.35×108/cm2 in the calculations.