US Patent 7261352 - Nanotweezers with control electrode

http://www.freepatentsonline.com/7261352.html

Manipulation of individual atomic and molecular particles was achieved with the scanning tunneling microscope and atomic force microscope in the 1980's and 1990's . More recently the development of nanotweezers using electrostatic actuation of opposing carbon nanotubes has allowed for more effective grabbing and holding of molecular objects. However, when grabbing molecules exhibiting electrically conductivity the nanotweezers may be shorted out. This patent from Samsung teaches an improved configuration that adds a control electrode so that the nanotubes forming the nanotweezers may be held at a common polarity. Claim 1 reads:

1. An apparatus for gripping nano-scale objects, the apparatus comprising: a probe including a base portion and a terminal portion; first and second nanotubes secured to the base portion of the probe, each of the first and second nanotubes including a protruding portion which extends past the base portion and the terminal portion of the probe; first and second electrodes formed on the base portion of the probe, the first and second electrodes being electrically connected to the first and second nanotubes, respectively; a third electrode disposed on the terminal portion of the probe; and a control circuit which is electrically connected to the first, second and third electrodes and applies a voltage to the first, second and third electrodes so that the first and second nanotubes are charged to a first polarity and the third electrode is charged to a second polarity opposite to the first polarity thereby causing the protruding portions of the first and second nanotubes to close due to an electrostatic force generated between the first and second nanotubes and the third electrode.