US Patent 7795041 Multi-polymer-coated magnetic nanoclusters

The present invention relates to multi-polymer-coated magnetic nanoclusters, aqueous magnetic fluids comprising same, and methods of their use in separation procedures. The multi-polymer-coated magnetic nanoclusters comprise a super paramagnetic core, with a first polymer attached thereto, which does not render the first polymer-super paramagnetic particle complex colloidally stable, and a second polymer attached thereto, which stabilizes the complex of multi-polymer-coated magnetic nanoparticles. Methods of use comprise methods of separation, including separation of expressed protein from cells and viruses expressing the same.