title: Magnetically Actuated Single-Walled Carbon Nanotubes.
abstract: We couple magnetic tweezer techniques with standard lithography methods to make magnetically actuated single-walled carbon nanotube (SWNT) devices. Parallel arrays of 4-10 μm-long SWNT cantilevers are patterned with one end anchored to the substrate and the other end attached to a micron-scale iron magnetic tag that is free to move in solution. Thermal fluctuations of this tag provide a direct measurement of the spring constant of the SWNT cantilevers, yielding values of 10(-7)-10(-8) N/m. This tag is also a handle for applying forces and torques using externally applied magnetic field gradients. These techniques provide a platform on which interaction forces between SWNTs and other objects such as biomolecules and cells can be measured in situ.
authors.affiliation: †Department of Physics, ‡School of Applied and Engineering Physics, §Laboratory of Atomic and Solid State Physics, and ∥Kavli Institute for Nanoscale Science, Cornell University, Ithaca, New York 14853, United States.
authors.forename: Samantha P
authors.initials: SP
authors.lastname: Roberts
authors.affiliation: †Department of Physics, ‡School of Applied and Engineering Physics, §Laboratory of Atomic and Solid State Physics, and ∥Kavli Institute for Nanoscale Science, Cornell University, Ithaca, New York 14853, United States.
authors.forename: Arthur W
authors.initials: AW
authors.lastname: Barnard
authors.affiliation: †Department of Physics, ‡School of Applied and Engineering Physics, §Laboratory of Atomic and Solid State Physics, and ∥Kavli Institute for Nanoscale Science, Cornell University, Ithaca, New York 14853, United States.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Martin
authors.affiliation: †Department of Physics, ‡School of Applied and Engineering Physics, §Laboratory of Atomic and Solid State Physics, and ∥Kavli Institute for Nanoscale Science, Cornell University, Ithaca, New York 14853, United States.
authors.forename: Melina K
authors.initials: MK
authors.lastname: Blees
authors.affiliation: †Department of Physics, ‡School of Applied and Engineering Physics, §Laboratory of Atomic and Solid State Physics, and ∥Kavli Institute for Nanoscale Science, Cornell University, Ithaca, New York 14853, United States.
authors.forename: Jonathan S
authors.initials: JS
authors.lastname: Alden
authors.affiliation: †Department of Physics, ‡School of Applied and Engineering Physics, §Laboratory of Atomic and Solid State Physics, and ∥Kavli Institute for Nanoscale Science, Cornell University, Ithaca, New York 14853, United States.
authors.forename: Alexander R
authors.initials: AR
authors.lastname: Ruyack
authors.affiliation: †Department of Physics, ‡School of Applied and Engineering Physics, §Laboratory of Atomic and Solid State Physics, and ∥Kavli Institute for Nanoscale Science, Cornell University, Ithaca, New York 14853, United States.
authors.forename: Paul L
authors.initials: PL
authors.lastname: McEuen
keywords: Single-walled carbon nanotubes; carbon nanotube spring constant; magnetic force spectroscopy; magnetic tweezers