The Brain

Biodegradable Sensors Monitor The Brain Before Harmlessly Dissolving

January 19, 2016 | by Justine Alford

Photo credit: J. Rogers/University of Illinois

As if going through brain surgery wasn’t bad enough, to monitor patients for subsequent complications, they need to have bulky devices implanted that can themselves serve as a source for further problems, like infection and even hemorrhage. And to make matters worse, surgeons need to remove the implant after its job is done, once again putting the patient at risk.

But what if there was a way to keep tabs on the brain without these invasive procedures? That’s the goal of a group at the University of Illinois at Urbana-Champaign, who has developed a dissolvable monitoring device that would eliminate the need for additional extraction surgery. While only tested on rat brains so far, the concept could be adapted for other areas of the body, potentially ushering in a new wave of minimally invasive medical monitoring technology.

Published in Nature, the innovative devices consist of tiny sensors, no bigger than a grain of rice, mounted on wafer-thin silicone membranes. Capable of detecting both temperature and pressure changes in the fluid surrounding the brain, all of the materials used were biodegradable and can be completely resorbed naturally by the body within just a few months.

To access the information gathered, the team built a wireless data-transmission device that sits atop the rodent’s head, which they hooked up to the sensor using dissolvable wires. While the wires themselves could slowly melt away into the body, the opening needed to join them to the external gadget presents a potential route for microbes to enter the brain and cause infection.

As a partial solution, the team made a second wireless device that was designed to sit on top of the animal’s skull, beneath the skin. Although they couldn’t make it completely biodegradable, because it didn’t need to be embedded deep into tissue or below the skull, the surgery needed to remove it would be easy.

"We found it to be 85 percent resorbable in terms of materials content," lead researcher John Rogers told IFLScience. "We think we know how to eliminate the last 15 percent and are working towards making it 100 percent resorbable, but even the remaining material doesn't seem to pose a significant risk as the device is only subdermal."

As before, this device was connected to the sensor using dissolvable wires. When they tested out the sensor’s capabilities, they found it to perform just as well as the standard, non-dissolvable devices used in the clinic today. Furthermore, it was stable and provided continuous readings for up to three days, a window the researchers say is relevant for the clinic.

The device isn’t quite ready for human trials yet, but that’s something the team is aiming toward. "Having used small animal models, the next step is to use larger models, and we think we're on a pathway that will culminate in technology relevant for human application," said Rogers. "In parallel, we're attempting to overengineer the devices so that they can operate over longer timeframes." All being well, Rogers added that an ambitious timeline of two to three years to commence human studies wouldn't be completely unrealistic. 

Image in text: Artist's impression of monitoring device. Julie McMahon

Photo Gallery

Tags