Researchers at Rice University have created what is certainly one of the most amazing nanomachines ever built: a tiny submersible vehicle with a tiny propeller that spins at a million RPM — all built from a single molecule.
This "nanosubmarine," made in the lab of chemist James Tour, is made from just 244 atoms. Its engine works like a bacterium's flagellum, whipping around in a circle whenever ultraviolet light causes its energy state to be excited. In the front (or bow) are two large "pontoons," which help the craft push its way through the atomic soup, and also fluoresce red light, allowing researchers to track the nanosubmarine's progress.
And what progress it makes: Each spin of the propeller may only move the sub forward 18 nanometers (a nanometer is a billionth of a meter), but it spins very fast. The result is, as Tour put it in the Rice news release, "the fastest-moving molecules ever seen in solution."
It's even more impressive when you consider that it's essentially forcing its way through a crowd of similarly sized molecules. "This is akin to a person walking across a basketball court with 1,000 people throwing basketballs at him," said Tour.
The nanosubmarines could conceivably be loaded with medicine and sent up a person's bloodstream for precision delivery, or made to ferry toxic chemicals out of water filters. The paper describing the molecular machine appeared in the journal Nano Letters.
"This is the first step, and we've proven the concept. Now we need to explore opportunities and potential applications," the project's lead, graduate student Victor García-López, said in the news release. "There's a way forward."