Patent ID: 8142892

Claim:
Bio-chemically active magnetic particle for use in a magnetic particle fluid suspension for selectively binding with at least one target molecule, the particle comprising: a) a non-magnetic component; b) a magnetic core/shell component comprising a ferromagnetic core material and a shell material, the ferromagnetic material comprising at least one fine ferromagnetic particle having zero coercive field or a given coercive field, the fine ferromagnetic particle(s) being associated with the shell material phase to provide a coercive field greater than that of the fine ferromagnetic particle(s); and c) an external coating designed to allow an affinity recognition for selectively binding the particle with at least one target molecule; wherein the shell material can be chosen either among an antiferromagnetic material, a ferromagnetic material of a kind different from the core ferromagnetic material, a transition metal or a metal oxide material; and wherein the Néel temperature of the antiferromagnetic phase is above 300 K.