Flow-rate dependent capture of circulating tumor cells in bio-functional microchannels

The capture of circulating tumor cells (CTCs) in shear flow is studied systematically by driving suspensions of breast cancer cells, with different EpCAM receptor expression levels, through microchannels functionalized with EpCAM antibody ligands at various densities. The dependence of cell capture efficiency on flow rate is established and can be described by an exponential function; a characteristic flow rate immerges as the most dominant parameter affecting the capture efficiency. Utilizing this characteristic flow rate as a scaling factor, all measured capture efficiencies for the tested receptor and ligand densities can be expressed using a single exponential formula. The effect of both ligand and receptor densities on the characteristic flow rate is found to be a product of two independent cumulative distributions.