On magnetophoretic separation of blood cells using Halbach array of magnets

Magnetophoretic separation has gained much attention in recent years due to its easy application and low-cost fabrication compared to other active particle separation techniques. Due to the different properties of white blood cells (WBCs) and red blood cells (RBCs), it is possible to manipulate and separate them using a magnetic field. In this paper, a simple microfluidic device is proposed to fractionate WBCs and RBCs from whole blood using magnetophoretic force applied by Halbach array of three permanent magnets. Plasma streams containing WBCs and RBCs enter a simple microchip fabricated by PDMS. Permanent magnets apply positive and negative magnetophoretic forces to the RBCs and WBCs, respectively. Two cladding streams containing blood plasma are used to concentrate the cells in the magnetophoretic area. A wide range of inlet velocities and different distances of magnets from the channel (d) are investigated. It is demonstrated that the volume flow rate of core, and cladding streams, total flow rate and the distance between magnets and microchannel affect the separation efficiency individually. The results reveal thatd = 0.1, 0.2, 0.3, 0.4, and 0.5 mm may lead to complete separation when core and cladding flow rates are 1 and 7 mu l/h, respectively.