Continuous focusing of biological particles by continuous immuno magnetic sorter: technique and applications

We have developed a device for continuous deviation-mode, open-gradient fractionation of strongly magnetizable particles based on an electrophoresis counter-flow chamber. A mixture of magnetically labeled and nonlabeled particles can be injected into a given continuously flowing chamber buffer. The particles pass the inhomogeneous magnetic field of the open-gradient electromagnet in two narrow streams. According to the magnetic moments, induced by the magnetic field, magnetically labeled particles are deviated. The nonlabeled particles pass the magnetic field with negligible interaction. The deviated particles are focused into a stream that is completely separated from the streams of the nondeviated particles. The streams are fractionated by the counter-flow technique and collected in different vials. A high sorting purity, depending only on the specificity of the antibodies or similar labeling techniques, and a high through-put rate of up to 10(9) particles per hour was achieved. This was experimentally shown both by test particles and blood cells. The vital conditions of these blood cells were maintained by magnetic sorting.