Cell sorting using immunomagnetic beads.

Immunomagnetic beads are uniform, polymer particles coated with a polystyrene shell that provides both a smooth hydrophobic surface to facilitate physical absorption of molecules, such as antibodies, and surface hydroxyl groups that allow covalent chemical binding of other bioreactive molecules, such as streptavidin, lectins, and peptides. Iron (III) oxide (Fe(2)O(3)) deposited in the core gives the beads superparamagnetic properties that lead to consistent and reproducible reactions to a magnetic field without permanent magnetization of the particles. These are the two qualities on which immunomagnetic separation (IMS) depends.