Design and simulation of high magnetic gradient device for effective bioparticles trapping

In this work, a design and simulation of high magnetic gradient device for effective bioparticles trapping is reported. The planar square-shaped microcoil and a V-shaped nickel iron (NiFe) alloy core is designed to guide and confine the magnetic flux lines through its small tip area and thus enhance the magnetic flux density and its gradient. The effects of core structure and coil parameters are analyzed using Finite element analysis (FEA) of two dimensional axial symmetry modeling. The simulation results revealed that the V-shaped magnetic core has significantly increased the magnetic flux density, its gradient and the magnetic force affecting on the beads sample. The highest magnetic flux density value, Bnorm is 66 mT is achieved for microcoil turns of N = 20, thickness of h = 5 μm, width and spacing of w = s = 50 μm and on tip surface area of 1 μm². Furthermore, a maximum magnetic force value of Fm = 1700 pN which is much higher than the drag force experienced by the magnetic beads in the microchannel has also been observed. Therefore, a promising effective trapping of the magnetic beads in the microfluidic channel is enable with this high magnetic gradient device design.