Assembling of nanoparticle arrays using microelectromagnetic matrix

Regular 2D-arrays from magnetic nanoparticle (NP) colloidal solutions were formed on the surface of a microelectromagnetic matrix chip with local configurations of magnetic field created by current-carrying conductors 2-20 μm wide. At the surface of the matrix, planarized by polyimide, there are local fields ≤200 Oe. The manipulation of Co, Fe3O4 and CoFe2O4 NPs was studied. NP arrays are formed in the center of circular traps with local field maxima, NPs assemble at the edge of conductors or they form special configurations, like toroids, due to superposed fields from various conductor segments.