An innovative micro magnetic separator based on 3D micro-copper-coil exciting soft magnetic tips and FeNi wires for bio-target sorting

Manipulation of cells or bio-targets is required in a variety of biological, diagnostic and therapeutic applications. In this paper, we present a novel magnetic separator for magnetic bead labeled-target sorting in microfluidic systems. This micro magnetic separator includes 3D micro copper coil, soft magnetic tips and FeNi wires. The magnetic tips and FeNi wires are first simulated and optimized by MagNet software to increase the magnetic force exerted on magnetic beads, and fabricated by microfabrication technology. The experiment results show the sorting ratio of the magnetic beads can be up to 92.5% with the current of 200 mA and the flow rate of 5 µL/min. The maximum sorting ratio can reach 78.4% for 100 CFU/mL E. coli O157:H7 sample with the current of 200 mA and the flow rate of 0.5 µL/min. On account of the miniaturization, high sorting efficiency, low excitation current, high level of detection automation and easy integration with micro magnetic sensor, this micro magnetic separation system can be a potential application in bio-target sorting and detecting.