With invasive surgery sometimes being a literal pain in the ass, it's no surprise that scientists are working tirelessly to minimize the need for such procedures. Now, however, China's Harbin Institute of Techonology is hoping to bypass fiddly surgery completely, thanks to its new tiny, swimming robots. Inspired by the fastest human method of swimming, the front crawl, these nanobots travel in a similar fashion, with their magnetic arms rotating and propelling them forward as the researchers apply a magnetic field to the bot's arms. This cleverly designed bot is pretty swift too, able to swim the front crawl at an impressive 10 micrometers per second. Thanks to its hefty arms and impressive speed, the bots have a momentum strong enough that they can even pass through thick liquids like blood in order to administer medicine from inside your veins.

It would take about two months for the bot to swim the length of an Olympic swimming pool – in that time, Phelps could swim almost 5 million lengths. But the nano-swimmer is fast for its size, and it's strong enough to pass through more viscous liquids, like blood, to deliver medicine from inside your veins. The front crawl is the fastest way for humans to swim. So Tianlong Li at the Harbin Institute of Technology in China and his colleagues built their swimming robot to mimic that motion. Each nano-swimmer is 5 micrometres long and has three main parts, connected together like sausage links by two silver hinges.