Microfluidic superparamagnetic bead based manipulator

Abstract

This paper describes the design and fabrication of a new detection system in which the dielectrophoresis and magnetophoresis phenomena were used as a tool for the manipulation of superparamagnetic microbeads within the microchannel. By exploiting the two facts that each superparamagnetic particle exhibit different dielectrophoretic forces at different applied frequencies and do not exhibit permanent magnetic dipoles in the absence of external magnetic field, we utilized this device to perform detection of beads. We found the transition frequency range for 2.8 mu m beads using our device. This device has higher trapping efficiency and less particle adsorption rate for beads. Bead based analysis revealed that high collection efficiency (similar to 90%) could be obtained from small amount of sample solution. This high throughput detection system offers a fast analysis of magnetic beads with their velocity being maintained as 9.8 mm/s. The magnetic field distribution on the beads and the bead flow at the channel cross-section for different dielectrophoretic conditions was obtained using CFD-ACE(+) simulation. Our novel platform would be a useful tool in manipulating different sized superparamagnetic microbeads paving way for a multiplex detection system.