Controlled Release and Separation of Magnetic Nanoparticles Using Microfluidics by Varying Bifurcation Angle of Microchannels

Lab-on-a-Chip based microfluidic devices facilitate simple, and continuous separation of nanoparticles in well-controlled and cost-effective manner. We fabricated Y-shaped microchannels with different bifurcation angles of the outlet legs for magnetic field-assisted separation. The bifurcation angles have shown the direct effect on the hydrodynamics at the bifurcation point. As a result, based on the external force, the migration of the particles from the main stream to the wall was observed. Trapping of particles were also observed at higher flow rates with different dispersion media. Bifurcation angles of microchannels at junction were =40 degrees, =78 degrees and =90 degrees. Separability of the magnetic nanoparticles has been found to be affected by the flow rates and the channel geometry. Trapping of the particles, and release from the trapped region were also observed which can be used for selective particles release for micro-reactor or micro-separator designs.