Patent ID: 7309439

Claim:
A device for transporting magnetic or magnetisable microbeads in a capillary chamber, comprising: a capillary chamber containing magnetic or magnetisable microbeads in a fluid; means for subjecting the capillary chamber to a substantially uniform magnetic field, to induce a permanent magnetic moment to the microbeads; an array of a plurality of coils adjacent to the capillary chamber, each coil for applying a complementary magnetic field on the microbeads parallel or antiparallel to said substantially uniform magnetic field, the coils in said array being arranged in overlapping relationship to avoid a local energy minimum between any two coils, with the center of each coil in the proximity of an edge of an adjacent coil; and means for switching the current applied to the coils to invert the field produced thereby, to selectively apply a driving force on the microbeads in the capillary chamber; the capillary chamber extending over the centers of the plurality of coils in the array to permit, in response to the application of said driving force by said switching means to successive coils, driving of the microbeads in the capillary chamber from center to center of adjacent coils and then to the next adjacent coils in the array whereby the microbeads can be driven over the array of coils.