As you'd expect, bodily fluids are far more difficult for the nanobots to swim through than water, thanks to the increased density. In a bid to prepare their tiny little machines for all manner of disgusting human fluids, the researchers also tested the nano-swimmers' movement speed by dunking them in serum. Unsurprisingly, their movement speed almost halved, with the bots only able to swim 5.5 micrometers per second through the fluid.

This test is crucial, as it measures how effectively swimmers could be used if coated in medicine and then injected directly into the bloodstream. Despite moving significantly slower through fluid than water, these little bots are actually far swifter in serum than other rival nano-swimmers, which makes them a good candidate for future nanobot medical research.

"It's exciting due to its speed and its really small size, just about the same size as a blood vessel," says Eric Diller, a microbot researcher at the University of Toronto. "It's small enough basically to go anywhere within the body."

While these swimmers are certainly impressive, the next generation of these nanobots will have to be built from biodegradable materials before they can be safely sent into the bloodstream. Diller goes on to say, however, that in the next five to 10 years, clinical trials could begin that test these bots on less difficult areas in the body, like the eyeballs or urinary tract.