Separation of blood in microchannel bends.

Most clinical chemistry tests are performed on cell-free serum or plasma. Therefore micro assay devices for blood tests require integrated on-chip microfluidics for separation of plasma or serum from blood. This is achieved by a new blood separation technique based on a microchannel bend structure developed within the collaborative microtele-biochip muTBC) project co-funded by the German Ministry for education and research (BMBF). Different prototype polymer chips have been manufactured with an UV-LIGA process and hot embossing technology. The separation efficiency of these chips has been determined with samples of human whole blood as well as diluted blood samples. The results show different separation efficiencies up to 90% for blood cells and plasma depending on microchannel geometry as well as cell concentration. As compared to present microfluidic devices for the separation of blood cells like filters or filtration by diffusion the microchannel bend is an integrated on-chip blood separation method, which combines the advantages of rapid separation times and a simple geometry.