The new metamaterial can be controlled remotely to rapidly transform its size and shape. Credit: Jorge Vidal/Rice University
Researchers have developed a new metamaterial that can almost instantly change its shape and size via a remote control, potentially transforming implantable medical devices.
The metamaterial is not only strong and stable, but also soft enough to reconfigure itself when needed. It can even deliver fluids wirelessly which may be valuable for future biomedical technologies.
“The metamaterial makes it possible to remotely control the size and shape of devices inside the body,” says Yong Lin Kong, an assistant professor of mechanical engineering at Rice University in the US.
“This could enable lifesaving capabilities such as precisely controlling where a device stays, delivering medication where it’s needed or applying targeted mechanical forces deep inside the body.”
Metamaterials are artificially made materials whose behaviour is shaped more by its physical structure rather than just its chemical composition. Because they are man-made, metamaterials often display properties that are not typically found in nature.
The newly designed magnetic metamaterial is made from soft silicone which can withstand loads of more than 10 times its own weight.
The researchers tested their material in temperatures as high as 100°C and as low as -20°C and found it was able to transform and remain in a stable state across the spectrum.
Given that a healthy human body temperature ranges from 36.5 to 37.5°C, the researchers suggest the material should function properly if implanted inside the body.
The material was also found to maintain its performance in harsh acidic environments like those found in the stomach, further demonstrating its potential to revolutionise ingestible medical devices.
“We programmed multistability, i.e. the ability to exist in multiple stable states, into the soft structure by incorporating geometric features such as trapezoidal supporting segments and reinforced beams,” says Kong.
The metamaterial can be switched between different states using an external magnetic field.
“These elements create an energy barrier that locks the structure into its new shape even after the external actuation force is removed,” says Kong.
The metamaterial’s entirely soft architecture makes it desirable for ingestible and implantable devices which, when rigid, are associated with gastric ulcers and punctures, and inflammation.
“We are now leveraging this metamaterial to develop ingestible systems that may one day treat obesity in humans or improve the health of marine mammals,” says Kong.
“We are collaborating with surgeons at the Texas Medical Centre to design wireless fluidic control systems to address unmet clinical needs.”
The research is published in Science Advances.