Flow rate optimization for the quadrupole magnetic cell sorter.

The quadrupole magnetic cell sorter is a form of split-flow thin-channel (SPLITT) separation device. It employs a quadrupole magnetic field and annular channel geometry. Immunomagnetic labels are used to bind to specific receptors on the surface of the cells of interest. It is the interaction of these labels with the magnetic field that brings about the selective isolation of these cells. The SPLITT separation devices have generally been based on parallel-plate geometry, usually with effectively constant field strength applied across the channel thickness. The nonconstant field strength and annular channel geometry of the magnetic cell sorter require that a new strategy be developed for optimization of inlet and outlet flow rates. We present such a strategy here based on a consideration of certain specific cell trajectories within the system.