'Microbots' hunt down disease

The tiny robots can be targeted to attack and destroy tumours

A tiny robot smaller than a grain of rice could soon be sent through the body tracking down disease and destroying it.

A team of scientists from Japan have developed tiny spinning screws that can swim along veins.

The screws could then be used to ferry drugs to infected tissues or even burrow into tumours to kill them off with a hot lance.

Kazushi Ishiyama, at Tohuku University, in Japan, designed his swimming micromachines based on cylindrical magnets, just eight millimetres long and less than a millimetre in diameter.

Targeting treatments to the site of tumours is an incredibly useful tool

Sara Hiom, of the CRC

Targeted treatment

Sara Hiom, of the Cancer Research Campaign (CRC), said the technology could lead to adaptations for all kinds of complex surgery.

"This is a novel surgical concept for delivery of treatment to precise areas within the body, but a good deal more research is needed before these magnetised robots can be hailed as a new type of therapy.

"Targeting treatments to the site of tumours is an incredibly useful tool, especially for those that are difficult to operate on, such as in the brain."

Mr Ishiyama made two prototypes to test his idea - the first was designed to move in liquids and the second to swim and burrow into tissue.

He found the device could screw itself through two centimetres of steak in just 20 seconds.

Because the spinning devices are so small Mr Ishiyama believes they could be injected into the body using standard hypodermic needles.

Once inside they could then be steered round the body magnetically, carrying drugs to the site of infection.

He said: "Using a 3D magnetic field supply system and controller, we can steer the machine in any direction."

Destroy tumours

One device has even been armed with a tiny metal spike, which can be heated up and then used for destroying cancerous tissues.

Mr Ishiyama said the technology, which he plans to exhibit at the Joint European Magnetic Symposia in Grenoble, this summer, could have a distinct advantage over standard tools such as catheters.

He said: "If our machines become smaller than catheters, they could be used for treatment in very thin blood vessels, like in the brain."

But Edwin Jager, of Linkoping University, who is designing tiny robots to manipulate single cells in the body said doctors were understandably cautious about allowing these microbots being allowed to float freely through the body.

He said that if one blocked a blood vessel it could have disastrous consequences and he added that the Japanese prototype might be too long to safely navigate some of the tighter turns in blood vessels.

The research is published in New Scientist.