Microfluidic on-demand particle separation using induced charged electroosmotic flow and magnetic field

Abstract Although microfluidic devices are widely used for pathogen separation, they are highly sensitive to operating conditions which restricts its applications. Here, a magnetophoretic microfluidic device that benefits from characteristics of electroosmotic flow is described. The device is capable of separating magnetic particles (MPs) from human blood in considerably wide ranges of conditions with a perfect efficiency. The device includes two adjacent fluidic channels for the injection of blood containing particle-bonded pathogens and the buffer solution with a slit at the middle for shifting particles to the outlet. Integrating a conductive surface across the slit creates a manageable flow vortex that assists magnetic field to overcome drag force of particles and boosts their upward movement towards the slit. Obtained results indicate that by adjusting the strength of magnetic field and electric potential, a perfect on-chip separation is achievable for particles in the size range of 100 nm to 2.5 µm. Being significantly efficient in such a large range of operating conditions makes the device extremely versatile for targeting various particle-bonded pathogens.