Patent ID: 7474184

Claim:
Hybrid magnetic tweezers comprising paired mirror image hybrid magnetic structures, wherein each of said hybrid magnetic structures comprising: a. a non-magnetic base; b. a ferromagnetic pole having a wedge-shaped tip, wherein said tip features a notch or concavity in cross-section to concentrate magnetic fields in a discrete region of interest inside the notch or concavity; c. at least two blocks of permanent magnet material; wherein the at least two blocks of permanent magnet material are assembled onto said base on opposite sides of and adjacent to said ferromagnetic pole, wherein the magnetization orientations of the blocks of permanent magnet material are oriented in opposing directions and orthogonal to the height of the ferromagnetic pole, and said blocks of permanent magnet material extend below the bottom edge of said ferromagnetic pole when assembled onto said base; and, wherein the ferromagnetic pole tip extends beyond each block of permanent magnet material, wherein the shaped tip is angled or bent from 0 to 90 degrees relative to the ferromagnetic pole, and wherein the magnetic field strength in the region of interest at least 1.0 Tesla.