Microelectromagnets for the control of magnetic nanoparticles

A microelectromagnet matrix and a ring trap that position and control magne tic nanoparticles are demonstrated. They consist of multiple layers of lith ographically defined Au wires separated by transparent, insulating polyimid e layers on sapphire substrates. Magnetic field patterns produced by these devices allow microscopically precise control and manipulation of magnetic nanoparticles. A microelectromagnet matrix produces single or multiple peak s in the magnetic field magnitude, which trap, move, and rotate magnetic na noparticles, as well as electromagnetic fields to probe and detect particle s. Microelectromagnets are new tools with which to study and manipulate nan oparticles and biological entities. (C) 2001 American Institute of Physics.