Design modification of a biochip microchannel separator with integrated curve constrictions for enhanced separation behaviour

This paper reports a design modification of a biochip microchannel plasma blood separator. Among the three geometric characteristics, i.e. bifurcation, constriction and bending channel, which have been widely used in promoting biofluid separation, the original separator (Figure 1) has put the focus on the bifurcation effect and also adopts a constriction at the inlet end to implement some constriction effect. This modification is targeted to a strong integrative application of these three channel geometries characteristics. For this purpose, curve/arc constrictions are implemented inside the bifurcation region between bifurcations, so that both constriction and bending channel effects can be effectively fulfilled at each bifurcation to increase the effectiveness. Both 2D and 3D designs for fulfilling this modification are offered. The flow field and separation process in the modified 2D biochip are analyzed using computational fluid dynamics (CFD) technique and compared with the original separator. Comparably the modified design leads to more volumetric separation of plasma rich fluid from the side channels and results in low flow rate ratio due to the increased channel resistance in the main channel. Improvements in using constriction and bending channel effects have been numerically evidenced.