Some day, it may be possible for tiny squishy biomedical robots to make their way through people's bodies, without being tethered to an external power supply or control unit. We've recently gotten a step closer to that being a reality, thanks to 3D-printing tech that produces magnetically-responsive devices.

Led by Prof. Xuanhe Zhao, a team of researchers at MIT started by creating an elastomer 3D-printing ink that is infused with tiny magnetic particles. As that ink is being extruded by a 3D printer, an electromagnet that's placed around the printer's nozzle causes all the particles that are passing through to be magnetically oriented in the same direction. That direction is determined by the direction of the electromagnet, which can be changed.

This means that by altering the magnet's direction as a print job is in progress, it's possible to create an object in which the particles are oriented in different directions, in different sections of the object.

When that flexible object is subsequently subjected to an external magnetic field, those sections will respond by moving in different ways, depending on the orientation of their particles. This causes the object to change its shape, and by moving the source of the magnetic field, it's possible to get the object to change back and forth between multiple shapes.

So far, the technology has been used to produce items such as a tube that squeezes shut, a sheet that folds and unfolds, and a spider-like device that is capable of crawling, rolling, snatching a passing ball, and even enveloping a pill and then carrying it across a table.

"We think in biomedicine this technique will find promising applications," says Zhao. "For example, we could put a structure around a blood vessel to control the pumping of blood, or use a magnet to guide a device through the GI tract to take images, extract tissue samples, clear a blockage, or deliver certain drugs to a specific location. You can design, simulate, and then just print to achieve various functions."

A paper on the research was published this Wednesday in the journal Nature. Some of the 3D-printed objects can be seen in action, in the following video.

Source: MIT