Microfluidic System as a Tool for Magnetic Separation of Human Cells with Diagnostic Relevance

A new microfluidic system was realized by means of a specially designed chip from silicon and glass. Magnetic disks were located above and below this chip. The transportation, mixing, incubation and the chip based separation procedure of the cell-magnetic bead suspension is caused by pumps and the rotation of permanent magnets arranged outside the chip. A high efficiency of attachment to the appropriate target cells from blood or other fluids is realized since the magnetic beads were functionalized with antibodies or a special Fab-Streptamer (R) technology. In comparison with monoclonal antibodies this technology allows the release of the beads from the target cells after separation by means of added D-Biotin to the target cell-magnetic bead suspension. The unlabelled target cells and the beads are ready for further use. In comparison with commercial separation systems, the benefit of the new microfluidic system in combination with the Fab-Streptamer-magnetic beads is the continuous fluid flows is the increased cost-effectiveness based on reduced incubation time, reduced magnetic bead concentration and re-usable target cells. Automized measurement of real blood samplesfrom cancer patients and the detection of the separated cells by means of a flow-cytometer (FACS) are ongoing.