Recently, China's Harbin Institute of Technology has led the development of a new type of robot that can swim in human blood vessels and target drugs. This article was compiled from New Scientist, entitled "Tiny robots swim the front crawl through your veins" article.

It's not a swimmer, Michael Phelps, but this tiny magnetic robot can move in liquid at 10 microns per second. It is small and powerful enough to deliver drugs from human veins through more viscous liquids, such as blood.

Freestyle is the fastest way for humans to swim. So Tianlong Li and his colleagues at the Harbin Institute of Technology in China let game robots mimic the action.

Each nano swimmer is 5 meters long and has three main sections, such as two silver hinge sausages connected together. The body is made of gold, with two magnetic arms made of nickel on either side, and a magnetic field applied to the micro robot to move the arm.

As the researchers switched the magnetic field back and forth, the nano swimmer's arm rotated and pushed forward, just like a swimmer's arm crawled forward in freestyle.

"The invention is exciting because of its speed and small size and the same size as the blood vessels," says Eric Diller Diller of University of Toronto in Eric, canada. It's small enough to basically go anywhere in the body."

Because body fluids are thicker than water and are difficult to swim through, researchers have tested their nano swimmers in serum. A robot can swim only 5.5 microns per second, but still faster than other similar micro machines.

For the delivery of targeted drugs without invasive surgery, these nano swimmers can be coated with drugs and injected into the bloodstream, which can be roughly controlled by an external magnetic field.

Because of the small size, individual nano swimmers will not be able to carry enough drugs to actually help. "Maybe we'll have to use one thousand robots," Diller said. "We can't track all these robots, so there's a lot of security and toxicity."

In the future, these micro machines must be made of biodegradable materials for use in the bloodstream. But, says Diller, clinical trials can begin in the next five to ten years for less complex areas such as the urinary tract or the eye. A single swimmer is injected into the eyeball where the drug can be delivered directly to the retina and removed, which is much easier than allowing a team of swimming robots to enter the circulatory system.