Massachusetts Institute of Technology (MIT) engineers have created miniature 3D-printed structures whose movements can be controlled with external magnetic fields.
The structures include a smooth ring that can wrinkle up, a long tube that squeezes itself shut, a sheet that folds itself, and a spider-like object that can crawl, roll and jump—and even wrap itself around a pill that it can carry across a flat surface.
The researchers made the structures out of a new type of 3D-printable ink infused with tiny magnetic particles. They then fitted an electromagnet around the nozzle of a 3D printer, causing the magnetic particles to align themselves in a single orientation as the ink passed through the nozzle.
By controlling the magnetic orientation of specific sections in the structure, the researchers are able to produce items that can change into intricate formations and even move—all according to how they respond to a magnetic field.
Instead of making entire structures with magnetic particles that have the same orientation, the team looked for ways to magnetize individual sections of the structures. This was achieved by changing the direction of the electromagnet around the printer’s nozzle as each section was printed; this tuned the orientation of magnetic particles in each section differently.
When exposed to an external magnetic field, each section would move in a distinct way that was determined by the direction of its magnetized particles—allowing the structure to wrinkle, bend or elongate. The researchers theorize that the structures should be able to take on more complex shapes and even move.
These devices hold substantial promise for biomedical applications. The robots could be inserted into a human body and controlled externally without the need for invasive surgery or wiring. And because of the structures’ fast response to magnetic stimuli, they could perform a number of tasks in a short amount of time. “We think there’s great promise in this idea of magnetic actuation, because it is fast, forceful, body-benign, and can be remotely controlled,” said Yoonho Kim, one of the researchers.
The technology could also be adapted easily. “We have developed a printing platform and a predictive model for others to use. People can design their own structures and domain patterns,” said Xuanhe Zhao, professor in MIT’s Department of Mechanical Engineering and Department of Civil and Environmental Engineering. “By programming complex information … one can even print intelligent machines such as robots.”
Read more about how 3D printing is changing the biomedical field at Open Source Innovation Could Put a 3D Bioprinter in Your Living Room.