Medical crawlers small enough to inspect brain blood vessels

An origami project could revolutionise medical procedures involving the brain and spinal cord.

Doctors have created a robot small enough to be injected into patients.

A project that began when a group of scientists set out to create the world’s smallest origami object could revolutionise medical procedures involving the brain and spinal cord.

Having learnt how to fold materials that measure an atom across, the scientists have produced a microscopic, bug-shaped robot tiny enough to crawl through the blood vessels of the brain.

“The crawler” is the smallest robot yet to carry its own computer circuitry. Measuring 70 ­microns, about the width of a very thin human hair, it can pass through a hypodermic needle unscathed.

Each four-legged crawler can carry about a million transistors on its body — about the same number that powered the Nintendo 64, one of the most popular video games consoles of the 1990s.

Marc Miskin of the Univer­sity of Pennsylvania, who led the research team, said hordes of crawlers could one day be ­injected into patients to inspect the structure of spinal cords or to track the activity of single ­neurons inside the brain. Versions could be built to detect the heat emitted by infections or to deliver beneficial bacteria to rescue an ailing digestive system.

“When I was a kid, I remember looking in a microscope, and seeing all this crazy stuff going on (at a cellular level). Now we’re building stuff that’s active at that size,” he said.

The robot is the latest tiny contraption to evoke comparisons with the 1966 film Fantastic Voyage, in which a submarine of scientists is shrunk to microscopic size and is then injected into the blood stream of a colleague to save his life.

The bodies of Dr Miskin’s ­robots were formed from a rectangular skeleton of glass, topped with a thin layer of silicon into which the researchers etched its electronic components. The prototypes also include ­either two or four silicon solar cells, which provide power.

Folding techniques borrowed from origami were incorporated into the four legs. When power is supplied the platinum in the leg expands, while the titanium ­remains rigid. This causes the limb to bend. Each leg is about 100 atoms thick. “Each robot carries a body that’s 1000 times thicker and weighs roughly 8000 times more than each leg,” Dr Miskin said. “We found out you can inject them using a syringe and they survive — they’re still intact.’’

The research will be presented at the American Physical ­Society in Boston.

The Times