  Previous devices to separate cells by the characteristic force they
experience due to dielectrophoresis, which depends on the size and electric
properties of the particle, were limited by the flow rates and particle
concentrations separation could be achieved at. To unlock the potential of
Lab-on-a-chip technology to create flexible, efficient and multifunction
devices at low cost it is necessary to increase the rates at which separations
can be performed. Here we present a device capable of high throughput
continuous separation of cells from microparticles and demonstrate separation
at 7 uL/min in a microchannel with a high density of cells and microparticles
in the sample of 10^8-10^9 cells/mL. This device uses the characteristic
response of the particles due to dielectrophoresis to provide the initial
separation before crucially focusing the particles into completely separate
particle streams allowing the operation at high flow rates and particle
concentrations. The device is demonstrated with the separation of polystyrene
(PS) beads 8 microns, 25 microns and human dermal microvascular endothelial
cell line (HMEC-1 cells) and human liver cell line (HepG2 cells) suspended in a
DEP buffer solution. We show that it is possible to achieve not only high flow
rate separation but also high sample purity with, after separation and
focusing, one output containing 100% cells.
