Hybrid cell sorters for on-chip cell separation by hydrodynamics and magnetophoresis

The classification of cells is important for medical diagnosis and medicine research. A micro-scale analysis system for blood allows immediate diagnosis, regardless of time or location. Rapid handling of biological cells is required for the development of lab-on-a-chip and point-of-care technologies. In previous papers, the reported sample solution flow rates for hydrodynamic cell separation ranged from 0.1 to tens of μl min^-1. This paper proposes a hybrid cell sorter that combines hydrodynamics and magnetophoresis. This cell sorter is proposed for improving the classification efficiency of a virtual impactor-based cell sorter and for permitting the hydrodynamic cell separation with high throughput. In addition, its performance has been evaluated in the classification of Jurkat cells and blood cells. In the Jurkat cell experiment, the classification efficiency of Jurkat cells at the major outlet decreased from 70 to 50.8% with the proposed hybrid scheme. The flow rate for cell separation was 1 ml min^-1. The classification efficiency of red blood cells (RBCs) increased from 75.2 to 86.8% with the application of a magnetic field. Also, the classification efficiency of white blood cells (WBCs) decreased from 83.8 to 70.9% with an applied magnetic field. Experimental results demonstrated that the classification efficiency of blood cells can be modulated and enhanced by magnetophoresis and that the hybrid cell sorter has potential for lab-on-a-chip applications.