At the University of Houston researchers are working to develop diagnostic and therapeutic devices that can be steered and powered using the magnetic field of an MRI scanner.
So far the researchers have been able to get blocks about two centimeters on a side to move in predetermined ways inside a specially-built box. They hope to be able to eventually manipulate devices smaller than a millimeter in diameter.
The other issue the investigators are addressing is the ability of the MRI-powered devices to perform energy intensive tasks, such as slicing tissues or injecting a drug. Currently the devices can move around, fairly gently, within their box, but getting them to act forcefully has required a bit of creativity. They relied on the concept of a Gauss gun, a type of linear accelerator powered by magnets, and resonant vibrations to generate enough force within one of the devices to power an injecting syringe.
Here’s a video from the University of Houston that gives a good idea for how the technology functions: