Collection of rare target cells in clinical samples such as disseminated tumor cells in peripheral blood or fetal cells in maternal blood poses difficult challenges to currently available cell separation methods. A novel, two stage microfluidic system enabling highly efficient and specific concentration of rare target cells has been developed. It uses immunomagnetic separation in fluidic channels to isolate target cells to nanoliter volumes from milliliters of blood. Particle trajectory modeling accurately predicts optimal flow rates for near 100% efficient capture. In the first stage a magnetic gradient is applied to a shallow channel. Labeled cells move toward the channel surface and are subsequently siphoned into a second stage channel bordered by a thin ferromagnetic wire. Cells line up with the magnetic field gradient formed by the wire where they can be processed using microfluidic reagent volumes. Observation using both transmission and epi-fluorescence optics is possible. The two stage flow- through design allows the rapid processing of large sample volumes while retaining highly efficient capture. Experiments using carcinoma cells spiked into mouse blood suggest the devices could outperform the current immunocytochemistry gold standard for selectivity of 1 : 10E6 (rare target cells : white blood cells).
Journal: TechConnect Briefs
Volume: 1, Technical Proceedings of the 2005 NSTI Nanotechnology Conference and Trade Show, Volume 1
Published: May 8, 2005
Pages: 179 - 182
Industry sectors: Advanced Materials & Manufacturing | Medical & Biotech