Researchers have installed a molecular engine into a "car" just a few billionths of a metre long. Measuring just 3 by 4 nanometres, around 20,000 of the cars could be parked on the tip of a human hair.
Jim Tour and his colleagues at Rice University (USA) have done it again.
The nano-car's molecular motor contains a pair of bonded carbon molecules that rotate in one direction if illuminated by a specific wavelength of light. After fixing the molecular engine to the car's chassis and shining a light on it, Tour's team confirmed that the engine was running by using nuclear magnetic resonance to monitor the position of the hydrogen atoms within it.
But the car was not released to drive itself along. "It's analogous to building a race car and putting it up on blocks," Tour said. "Now it's a question of getting it out on the track."
The previous version of the nano-car moved along a flat gold surface. But this would stop the new motor from working as the energy collected from light would drain into the gold molecules.
A non-metal track should allow the engine to work, but this makes observing the car in action problematic as the scanning tunnelling microscope normally used needs a metal base. Other forms of microscopy either do not have the power to resolve the car properly, Tour says, or require the use of other surfaces that are unsuitable.
"This shows a general problem with nanotechnology right now," Tour says. "We only have crude tools and that slows development down."
Yep. As Richard Feynman said, "The principles of physics, as far as I can see, do not speak against the possibility of maneuvering things atom by atom. It is not an attempt to violate any laws; it is something, in principle, that can be done; but in practice, it has not been done because we are too big."
We're getting closer, but we're still too big.
Although we have a relatively long way to go, our crude tools have improved quite a bit since Feynman spoke those words in 1959. New developments every day are moving us closer to the ability to build high-performance products with atomic precision.
Today, nanotechnology is at a state similar to the airplane in 1900, or the computer in 1950. But progress is moving quickly, and when molecular manufacturing is achieved, it will have the impact of all the technology in the 20th century, shrunk down into just a few years. Get ready!