Effect of magnetic field strength and flow rate on separation distance and recovery rate in a cell-separating microfluidic device

Abstract This study presents a numerical investigation into the effect of magnetic field strength and sheath flow rate on the performance of a magnetophoretic Lab-on-a-Chip (LOC) device for cell separation. Simulations were conducted using a two-dimensional model based on the principle of negative magnetophoresis to achieve label-free separation of particles with diameters of 15.8 and 5.8 µm. The results revealed that separation distance exhibited a non-linear dependence on sheath flow rate for a given magnetic field, with a distinct peak observed at optimal conditions. At a magnetic field strength of 350 mT and a sheath flow rate of 20 μL/min, the device achieved a maximum separation distance of 1.023 mm and a 100 % recovery rate. Furthermore, the separation distance increased at a diminishing rate with rising magnetic field strength and buffer flow rate, following an exponential profile. The optimized LOC design, based on computational fluid dynamics (CFD) simulation, demonstrates that precise control of flow and magnetic parameters can significantly enhance the separation efficiency and recovery rate of microfluidic devices.