Self propelled nanorotors

A fully man-made nanomachine has been developed by Canadian scientists.

Nanotechnology is developing rapidly and many scientists are working towards creating nanomachines. One important challenge is to make a tiny generator capable of providing power to accomplish a particular task. Although biomolecular motors have been used to drive nanodevices, they are complex and restricted by physiological conditions. In contrast this new nanomachine is simple, can be constructed from a variety of elements and uses an environmentally friendly fuel.

Geoffrey Ozin and colleagues from the University of Toronto have made a nanorod about 500 times thinner than a human hair, comprising two different metals; in this case gold and nickel. Very thin layers of these metals are deposited on top of one another to give a pattern like a conventional barcode.

One of the metals, nickel, can catalyse the decomposition of hydrogen peroxide to produce oxygen gas, propelling the nanorod through the solution. Thus when the nanorod is placed in a hydrogen peroxide solution it can propel itself through the solution in a straight line.

The group created a self propelled nanorotor by tethering one end of the nanorod to the surface of a silicon wafer. These tiny propellers revolve at a constant speed until the hydrogen peroxide supply is exhausted, but start to rotate again when the fuel is reintroduced.

While rotational motion is an important step in making nanomachines, Ozin concedes that it will be a challenge to incorporate the rotors into a fully functional nanomachine. He is looking forward to this, saying: ’We need to assemble and integrate our synthetic nanomachines into more complex architectures so that the rotary motion can be harnessed to accomplish a variety of tasks.’

Lorna Jack