A device for separating a sample of cells suspended in a bio-compatible ferrofluid is described. The device includes a microfluidic channel having a sample inlet, at least one outlet and a length between the same inlet and the at least one outlet, wherein a sample can be added to the sample inlet and flow along the microfluidic channel length to the at least one outlet. The device includes a plurality of electrodes and a power source for applying a current to the plurality of electrodes to create a magnetic field pattern along the microfluidic channel length. The present invention also includes a method of using said device for separating at least one cell type.