Magnetically Actuated Single-Walled Carbon Nanotubes.

Roberts, Samantha P; Barnard, Arthur W; Martin, Christopher M; Blees, Melina K; Alden, Jonathan S; Ruyack, Alexander R; McEuen, Paul L · Nano Lett · 2015

basic_science · Level V

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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.