NIH, DARPA-backed researchers develop wireless, dissolvable brain sensors

A rendering of the brain sensor and wireless transmitter monitoring a rat's brain--Courtesy of Julie McMahon, University of Illinois

Scientists have developed brain implants to monitor pressure and temperature after traumatic brain injury that dissolve over a few days. The idea is that these could be implanted during surgery on TBI patients in order to conduct subsequent monitoring, but then they would not require removal.

Researchers have thus far tested the sensors in saline solution baths. Next, they expect to test them as implants in laboratory rats. The devices are made mostly of polylactic-co-glycolic acid (PLGA) and silicone.

The NIH's National Institute of Mental Health (NIMH), the Defense Advanced Research Projects Agency (DARPA) and the Howard Hughes Medical Institute all contributed funding to the research. The technology was developed by scientists at Washington University School of Medicine in St. Louis and engineers at the University of Illinois at Urbana-Champaign who published their findings in the latest issue of the journal Nature.

"Electronic devices and their biomedical applications are advancing rapidly," said co-first author Dr. Rory Murphy, a neurosurgery resident at Washington University School of Medicine and Barnes-Jewish Hospital in St. Louis. "But a major hurdle has been that implants placed in the body often trigger an immune response, which can be problematic for patients."

"The benefit of these new devices is that they dissolve over time, so you don't have something in the body for a long time period, increasing the risk of infection, chronic inflammation and even erosion through the skin or the organ in which it's placed. Plus, using resorbable devices negates the need for surgery to retrieve them, which further lessens the risk of infection and further complications," he concluded.

TBIs are common--with about 50,000 patients in the U.S. dying annually from brain injury. When a patient presents with a TBI, it's essential for physicians to have a measure of intracranial pressure to assess the possibility of any further brain injury.

Measurements of brain pressure are conducted currently using sensors that may require wires, cause an immune reaction in the patient and require surgical removal. The use of advanced materials and device design could translate into bioelectric medical sensor that could be functional to track many bodily organs, including the brain.

"The ultimate strategy is to have a device that you can place in the brain--or in other organs in the body--that is entirely implanted, intimately connected with the organ you want to monitor and can transmit signals wirelessly to provide information on the health of that organ, allowing doctors to intervene if necessary to prevent bigger problems," Murphy said. "And then after the critical period that you actually want to monitor, it will dissolve away and disappear."

- here is the announcement and the Nature study