The successful capture of different sized fluorescently labeled ferromagnetic microbeads by different cell lines is reported here. The cells have subsequently been analyzed by flow cytometry and the degree of uptake was found to be dependent on the bead size/concentration and the incubation time. In contrast to previous studies where superparamagnetic beads had mainly been used, we show that ferromagnetic beads, which have two orders of magnitude higher magnetic moments, can be successfully incubated with biological cells. The design of a "Y''-shaped microfluidic device that was successfully used to hydrodynamically focus and sort the fluorescent beads is also presented here. (C) 2006 Elsevier B.V. All rights reserved.