Exploring contraction–expansion inertial microfluidic-based particle separation devices integrated with curved channels

Separation of particles or cells has various applications in biotechnology, pharmaceutical and chemical industry. Inertial cell separation, in particular, has been gaining a great attention in the recent years since it has exhibited a label-free, high-throughput and efficient performance. In this work, first, an inertial contraction–expansion array microchannel device, capable of passively separating two particles with diameters of 4 and 10 μm, was numerically studied. Then, the validated model was combined with curved geometries in order to investigate the effect of curve features on the separation process. The overall purpose was to investigate the interaction between the two different separation methods (separation with curved channels and with contraction–expansion arrays) to find an ideal model that can enjoy the merits of both contraction–expansion and curved channel based methods. Moreover, the relation between separation strength and the aspect ratio in the contraction and expansion zones of the simulated model as well as its height were examined. Then, a new model that combines the curved and the contraction–expansion geometries was tested for its efficiency. This new geometry showed that separation could be achieved with shorter lengths compared with straight contraction–expansion geometries.