Let’s just get this out of the way from the outset: this technology has absolutely nothing to do with the miniature submarine from the sixties sci-fi classic “Fantastic Voyage”.
Now that that’s clear, research out of Rice University led by James Tour has accomplished something perhaps even more impressive because it’s real. Tour and his team have designed and fabricated a molecule consisting of 244 atoms that can move within a liquid environment using a tail-like propeller powered by ultraviolet light.
What is really impressive about the nanoscale submarines is their speed. One wag of its tail can move it 18 nanometers. Not impressed? Consider that the tail can wag a million revolutions per minute (RPM), which translates to propelling the molecule about 2.5 centimeters per second. In nano-scale terms that’s really fast.
In research published in the journal ACS Nano, the speed of the 10-nanometer scale submersibles are fast enough that they can work their way through a solution containing molecules of the same size without being slowed down.
"This is akin to a person walking across a basketball court with 1,000 people throwing basketballs at him," Tour said in a press release.
The operation of the motor resembles the movement of a bacterium’s flagellum. The process involves four steps. In the first, when light hits the double bond that holds the rotor to the main body, it becomes a single bond. This removal of a single bond allows the rotor to turn a quarter rotation. This motor is seeking to get to a lower energy state, which leads it to jump to the next adjacent atom. This causes the rotor to turn another quarter step, and so goes the process while the light shines on it.
The longer-term aim of such a submarine would be to serve as a cargo delivery device with drug delivery being the most likely possibility.
Victor García-López, lead author and Rice graduate student, added: "This is the first step, and we've proven the concept. Now we need to explore opportunities and potential applications."
Dexter Johnson is a contributing editor at IEEE Spectrum, with a focus on nanotechnology.