Nanowires usually exist in the realm of extremely low Reynolds numbers at the level of 10-5 in suspension. In this regime, based on Stokes’ law, viscous forces dominate inertial forces. Previous work has shown that to induce motion on the nanowires, a relatively large force must be applied to overcome the large viscous drag. Here we fabricate monodispersed Au nanowires with large aspect ratios using template guided electrodeposition. Au nanowire surfaces can be functionalized through surface modifications to control their physiochemical interactions with biological systems.

We developed a method for translating, assembling, and rotating nanowires in suspension. This technique uses precise electric fields as “tweezers” that employ Lorentz forces and dielectrophoretic forces applied by strategically designed Au electrodes patterned by photolithography. Controlling these two forces allows nanowires to be transported to any predetermined location in two dimensions with any preferred orientation with a spatial resolution better than 300 nm. Metallic, semiconducting, and dielectric nanowires, as well as single-walled and multiwall carbon nanotubes can all be manipulated using this approach. We also have shown how electrical tweezers can be used to produce a variety of nanodevices including nanomotors and nano-oscillators. Nanowire motion control is even precise enough to target specific regions of interest within an individual cell. This novel subcellular manipulation technique may serve as a useful tool for targeted drug delivery applications. Future work is also proposed to study stimulation of intercellular communication and directed cellular development in vitro using this system.

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