Wired and a group of Argonne National Laboratory physicists really stretch the meaning of the word "robot" when it describes tiny magnetic specks that come together in liquid and move stuff around, but it does make for a neat headline, anyway: "Self-Assembling Minirobots Swim and Manipulate Objects."
Physicist Igor Aranson made "mini robotic doughnuts," as Wired put it, from tiny metal particles, 35 to 90 micrometers long, floating between a layer of oil and water. The resulting "robots" can be manipulated to open and close via alternating current and "swim" by way of a magnetic field. The researchers can manipulate the particles to carry payloads of between 150 microns and 3 millimeters. Still too large for any useful drug delivery into human cells.
Still, it's a beginning, so Wired asserts: "A movable 3-D robot could one day be used in medicine, delivering a payload through the blood stream to specific tissue."
For his part, Aranson is not exactly discouraging the SciFi dreaming. "Look at science fiction movies, they always have something like this," he tells Wired. "Think of the Sandman in "Spiderman 3"--he could break into small pieces of sand, reform and suddenly be a man again. So basically we are making things that are highly simplified, but similar."