title: Sub-100 nm confinement of magnetic nanoparticles using localized magnetic field gradients.
abstract: Ferromagnetic rods containing thin sections of diamagnetic metal create intense magnetic field gradients that attract and confine magnetic nanoparticles to regions of space as small as 20 nm. The rods (80 nm diameter) comprised alternating sections of CoNi ( approximately 350 nm) and Au (20-160 nm) formed by electrodeposition into porous polycarbonate membranes. Upon magnetizing the rods, large magnetic gradients (106-107 T/m) form at the boundaries between ferromagnetic and diamagnetic sections. These gradients attract and confine magnetic nanoparticles to attoliter volumes of space surrounding the rod. This method provides a new tool for generating intense, highly localized magnetic field gradients, by design, and confining magnetic nanoparticles in these gradients.
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA.
authors.forename: Adam R
authors.initials: AR
authors.lastname: Urbach
authors.forename: J Christopher
authors.initials: JC
authors.lastname: Love
authors.forename: Mara G
authors.initials: MG
authors.lastname: Prentiss
authors.forename: George M
authors.initials: GM
authors.lastname: Whitesides
mesh_terms: D003035:Cobalt / Q000737:chemistry; D004574:Electromagnetic Fields; D005290:Ferric Compounds / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D036103:Nanotechnology / Q000379:methods*; D009532:Nickel / Q000737:chemistry; D010316:Particle Size
chemical_list: D005290:Ferric Compounds; C000499:ferric oxide; D003035:Cobalt; D006046:Gold; D009532:Nickel