Soon, tiny robot doctors that swim in your bloodstream

Scientists have built tiny robots that need not be tethered to an outside controller and can one day be used to assemble medical devices inside the body.
Researchers from Carnegie Mellon University in Pittsburgh have created a simple version of micro-robots using rods made of magnetic materials.
Each robot is about 1 millimetre long and has two gripping arms. A magnetic field is used to move the robots and operate the grippers.
Previous gripping bots had to be tethered to an outside controller, making them unsuitable for use inside the human body. Other versions could not move and grip things at the same time, 'New Scientist' reported.

"We can move them while they are closed or open, it doesn't matter," said Metin Sitti of Carnegie Mellon University.
So far, the robots have transported small objects and built bridges out of Y-shaped rods.

Sitti hopes future versions could be injected into the body along with parts for micro-machines that would swim in the blood and help wounds clot.
The builder bot could then create the more advanced device while inside the bloodstream.
"We need to make things smaller to get inside the body easier, but if they are too small, they are not really useful. You want to assemble the robot inside the body," Sitti said.