Chemist Builds Single-Molecule Submarine That May Carry Medicine Up The Bloodstream

In a strange but outstanding feat of modern science, a chemist has built a itty-bitty, single-molecule submarine that, in addition to looking really cool, may one day float through our bloodstreams to deliver medicine.

The single-molecule submarine is comprised of 244 atoms and was built in chemist James Tour’s lab at Rice University, NBC News reported. Its propellers are more like a bacterium’s flagellum than the propeller of a real submarine, but they can spin at a million RPM and move the sub an inch per second.

Tour said that’s a “breakneck pace on the molecular scale,” Popular Mechanics added.

via GIPHY An example of how flagellum work.

The single-molecule submarine has two “pontoons” in the front that push the craft through a so-called atomic soup; part of the pontoons’ bodies glow with red light when hit with a laser. This isn’t just to give the nanosubmarine a flashy look, it helps researchers track its movements.

The motor of this little sub is energized by ultraviolet light. When this happens, “light, a double bond that attaches it to the body of the sub becomes a single bond, rotating the tail-like motor a quarter step. The motor rotates another quarter turn as it returns to a lower energy state,” Mechanics writer Jay Bennett explained.

The motors will keep rotating, moving the single-molecule submarines forward, as long as that light sources sticks around. These flagellum-like propellers help move the tiny sub through difficult solution, filled with molecules of about the same size. Tour had an interesting metaphor to describe just how difficult this would be for the single-molecule craft.

“This is akin to a person walking across a basketball court with 1,000 people throwing basketballs at him.”

The submarine can also move pretty fast at one inch per second. Tour said each spin of the propeller will edge the craft forward 18 nanometers — one nanometer is about one billionth of a meter, making it the “the fastest-moving molecules ever seen in solution.”

To see his single-molecule submarine in action, Tour headed over to North Carolina University, where a team sandwiched a drop of solution that contained many of these nanosubmarines between two microscope slides, then observed them with an advanced microscope that allowed them to watch the swiftly-moving craft. With a less-sophisticated microscope, the tiny subs would’ve shimmied out of focus so quickly they couldn’t be seen.

They shone ultraviolet light on them and, lo and behold, they starting spinning.

According to Popular Science, these teeny submarines can’t be steered yet, but if they figure out how, they can be used to carry medicine through the body. They can be loaded up with meds, then shoot up a patient’s bloodstream in order to deliver that medicine with precision. In another scenario, the mini-subs could be used to remove toxic chemicals out of water filters.

(Which all sounds a little reminiscent of the 1980s sci-fi film Innerspace, without Dennis Quaid steering it, of course.)

“This is the first step, and we’ve proven the concept. Now we need to explore opportunities and potential applications,” said the project’s lead, graduate student Victor García-López. “There’s a way forward.”

The Rice team has already built mini-vehicles. Ten years ago, they created the first nanocars, also single-molecule and comprised of four wheels, two rotating axles, and a suspension system. They rolled across a grid service at first, but eventually, the team built some that were self-propelled.

According to the Daily Mail, micro machines like this single-molecule submarine have been designed and built plenty of times before. But these other mini-craft have used or generated toxic chemicals. Because the motor in Tour’s nanosub works like a flagellum, this isn’t a problem.

[Image via danilo ducak/Shutterstock]