Published: 4 August, 2005

Work is ongoing in quest to develop autonomous nanobots

Have nanobots already been created? What are nanobots made out of? Are they decomposable or will they just build up? What do they use for a power source?

Electromechanical nanobots are autonomous robots on the scale of tens to hundreds of nanometers (one nanometer is one billionth of a meter). These robots generally contain an internal power source, a processor "brain", and a method of transportation. An electromechanical robot is one that combines electric and mechanical processes for the above robotic components.

From an electromechanical standpoint, nanobots have not yet been created successfully. Many scientists are working to reduce robot components down to the nanoscale. The biggest obstacle is the power source. Most robots currently use solar cells or batteries for power. However, these are both large, limiting mechanical robots to a minimum scale of millimeters. One promising idea for nanoscale power supply is a radioactive thin film, taking advantage of particles released in the decay of certain atoms. A radioactive power supply will easily scale down to the hundred-nanometer regime, and will never require replacement.

Nanobots will most likely be made of silicon - the same material used to make the microchips used in all electronic devices. Silicon is a popular choice for nanomechanical robot design because it is strong and can easily be manipulated to have various electronic properties. Consequently, as with any electronic device, nanobots are not decomposable. However, with some clever and costly processing, these nanobots can be recycled. The recycled impure silicon can be used for solar cells and other low-grade applications.

The smallest successful electromechanical robot to date was created by Kris Pister et al. at U.C. Berkeley. His solar-powered robot is 8.5 mm long, and moves forward in a biped shuffle. Each leg is equipped with a series of motors made of microscopic silicon components called transducers that transform the solar-cell power into mechanical work. Though Pister's robot is still macroscopic, it presents a promising first step to downscaling autonomous electromechanical robots.

One alternative to electromechanical robots is small molecular cluster devices that react to environmental forces in order to move. It is therefore questionable if such nanobots are truly autonomous. While additional work is required to shrink electromechanical robots to molecular robot scales, many new innovations in transducer, power supply, and processor design and integration ensure quick progress towards the realization of the nanobot.