Magnetic/flow controlled continuous size fractionation of magnetic nanoparticles using simulated moving bed chromatography

The use of magnetic nanoparticles shows a steadily increasing technical importance. Particularly in medical technology disciplines such as cancer treatment, the potential of these special particles is increasing rapidly. Magnetic nanoparticles are particles with a submicron size, and consist mostly of magnetite-containing composites. An important quality parameter of such particles is a particle size distribution as narrow as possible, which can only be obtained to a certain degree by synthesis. Apart from ultracentrifugation, there are so far only methods on an analytical scale to narrow the size distribution as a post-processing step. We present a method based on magnetic chromatography, by which high separation efficiencies at yields of up to 99.9% are achieved. The novel technique is based on a competition between the magnetic interaction of the nanoparticles and the separation matrix, as well as the hydrodynamic forces. Furthermore, the method is extended using a continuous mode, namely simulated moving bed chromatography, to obtain potent space-time yields of up to 2.94 g/(L*h). For those reasons, this novel continuous magnetic chromatography method offers high potential for large-scale refinement of magnetic nanoparticles while fulfilling sophisticated quality criteria for high-technology applications.