Magnetophoretic microdevice for size-based separation: model-based study

This article proposes a novel a magnetophoretic microfluidic device for separation of magnetic microparticles based on size and subsequently carries out simulation-based parametric analysis of the same. The microfluidic device is constructed with two inlets as well as two outlets and employs a soft magnetic element subjected to a uniform magnetic field to create the desired spatially varying magnetic field inside the microchannel. The first inlet introduces the sample while the second inlet is for introducing sheath flow to focus the microparticles close to the microchannel's bottom surface prior to being deflected by magnetophoresis to the appropriate outlets. Parameters such as location of outlets, microchannel height, fluid velocity, and ratio of inlet and of outlet flow rates influence the movement of microparticles inside the microchannel and the associated performance metrics. Parametric study, carried out using 1 and 10 µm magnetic microparticle suspended in water, revels that the best performance metrics occur when flow rate ratios are maintained as low as possible. In addition, the performance metrics are examined for different designs to determine the optimal value of the location of the outlet associated with large microparticles.