Magnetophoretic label-free cell separation using paramagnetic solution in a microchannel

Abstract

This thesis presents a diamagnetic repulsion magnetophoresis system for enhancing separation effect of different size particles by tuning the magnetic susceptibility of medium using paramagnetic solution. To demonstrate this system, various concentrations of paramagnetic solution were applied to separate 8- and 10-$\mum$ polystyrene beads in a microfluidic channel with a magnetic field. As the concentration of paramagnetic solution increased, the distance between two different beads was widened as well as the deflection of those beads became larger under the magnetic field. For cell separation, red blood cells and U937 cells were applied with various concentrations of paramagnetic solution. By using 40 mM gadolinium diethylenetriaminepentaacetic acid solution, we have achieved label-free separation of U937 cells from red blood cells using paramagnetic solution. The separation purity and throughput was 90 % and $1\times10^{5}$ cells/h, respectively. This new approach would be a powerful tool for label-free separation of rare cells and for multi-target separation with high resolution.