Robotic arm

Engineering

Ecology

Biology

Materials science

Layer (electronics)

Etching (microfabrication)

DNA origami

Silicon

Mechanical engineering

Nanotechnology

Helix (gastropod)

Composite material

Nanostructure

Bundle

Nanoscopic scale

Optoelectronics

Snail

Science

Electrically driving a DNA arm Most nanoelectromechanical systems are formed by etching inorganic materials such as silicon. Kopperger et al. improved the precision of such machines by synthesizing a 25-nm-long arm defined by a DNA six-helix bundle connected to a 55 nm-by-55 nm DNA origami plate via flexible single-stranded scaffold crossovers (see the Perspective by Hogberg). When placed in a cross-shaped electrophoretic chamber, the arms could be driven at angular frequencies of up to 25 Hz and positioned to within 2.5 nm. The arm could be used to transport fluorophores and inorganic nanoparticles. Science , this issue p. 296 ; see also p. 279

A self-assembled nanoscale robotic arm controlled by electric fields