Magnetic concentration of the flowing MagMSCs. (A) A schematic illustration of the microfluidic system. The MagMSCs were injected into the tube, and the flow rate was controlled by using a syringe pump. Cells were captured by using an NdFeB magnet located beside the tube. (B) Representative images of cell accumulation in the segment close to the magnet at velocities of 4 mm/s, 20 mm/s, 100 mm/s, and 500 mm/s. (C) The efficiency of magnetically captured flowing MagMSCs at different flow velocities. A negative relation was found between the flow velocity and the cell-capture efficiency. CE denotes capture efficiency.