One of the most popular sci-fi films of the 60s was “Fantastic Voyage” – and not just because it co-starred Rachel Welch. It was a time of great scientific achievement, atomic power and space travel. A time when it seemed within the realm of possibility that someday doctors, or at least their equipment, could be miniaturized and travel inside a human bloodstream like a submarine to destroy a clot. We’re not there yet but we’re one tiny step closer to the submarine with the invention of a microscopic propeller that can spin and steer through bodily fluids.
ACS Nano reports in its June 2014 issue that a team of Israeli and German scientists has developed a tiny screw-shaped propeller that can move in a thick fluid similar to the inside of an organism. How tiny? The silicon-and-nickel filament is 70 nanometers in diameter (100 times smaller than a red blood cell) and the entire propeller is 400 nm long. That’s ‘nanometers’ as in one billionth of a meter. The propeller is so small, the spin can be affected by nearby molecules, a phenomenon known as Brownian motion. It’s also smaller than the submarine in “Fantastic Voyage,” which was one micrometer.
The gelatinous fluid used to simulate the inside of the human body is hyaluronan – it’s the stuff that’s inside your eyeball. Using a weak magnetic field, the researchers were able to move the propellers through the gel and around the polymers that it contains. The nanopropellers exceeded the velocity of larger micropropellers and were easier to control.
Peer Fischer, one of the researchers, describes a possible application for the nanopropellers.
I can now think about targeted applications, for instance in the eye where they could be moved to a precise location at the retina.
The submarine in “Fantastic Voyage” also traveled through the eye and exited in a teardrop.
So, is it time to call the Combined Miniaturized Deterrent Forces and book seat on their next sub? Not yet, but a movie about the development of the nanopropeller would definitely be worth watching if it co-starred Raquel Welch.