Effect of micropost geometry on capture of circulating tumor cells

Circulating tumor cells (CTCs) are cancer cells that leak into the blood. CTCs can be captured using a set of microposts in a microchannel chip (CTC chip) that induces an antigen–antibody reaction. First, CTC capture experiments are performed on a conventional CTC chip at a flow rate Q = 1 mL/h. Subsequently, numerical simulation is performed using identical conditions to those employed in the experimental setup. A comparison between the numerical and experimental results shows that more CTCs are captured at a wall shear stress (WSS) ranging from 0.02 to 0.04 Pa. The existence of many walls with WSSs within the abovementioned range is effective for CTC capture. To investigate the effect of geometry, numerical simulations are performed under various post geometries. A channel with diamond-shaped posts (Square B model) shows that the WSSs of most walls ranged between 0.02 and 0.04 Pa at Q = 2 mL/h. A prototype of the new CTC chip with a Square B model geometry is fabricated, and its performance is evaluated. The results show that the CTC capture performance of the new CTC chip is significantly lower than that of conventional CTC chips. This indicates that post geometries significantly affect CTC capture performance.