Researchers have developed a new class of small, thin electronic sensors that monitor temperature and pressure within the skull – crucial health parameters after a brain injury or surgery – then melt away when no longer needed. This eliminates the need for additional surgery to remove the monitors and reduces the risk of infection and haemorrhage.
Similar sensors can be adapted for postoperative monitoring in other body systems as well, the researchers say. Led by John A. Rogers, a professor of materials science and engineering at the University of Illinois at Urbana-Champaign, and Wilson Ray, a professor of neurological surgery at the Washington University School of Medicine in St. Louis, the researchers have published their work in the journal Nature.
“This is a new class of electronic biomedical implants,” said Professor Rogers. “These kinds of systems have potential across a range of clinical practices, where therapeutic or monitoring devices are implanted or ingested, perform a sophisticated function, and then resorb harmlessly into the body after their function is no longer necessary.”
After a traumatic brain injury or brain surgery, it is crucial to monitor the patient for swelling and pressure on the brain. Current monitoring technology is bulky and invasive, Rogers said, and the wires restrict the patent’s movement and hamper physical therapy as they recover. Because they require continuous, hard-wired access into the head, such implants also carry the risk of allergic reactions, infection and haemorrhage, and could even exacerbate the inflammation they are meant to monitor.
The new devices incorporate dissolvable silicon technology developed by Rogers’ group. The sensors, smaller than a grain of rice, are built on extremely thin sheets of silicon – which are naturally biodegradable – that are configured to function normally for a few weeks, then dissolve away, completely and harmlessly in the body’s own fluids.
Rogers’ group teamed with Illinois materials science and engineering professor Paul V. Braun to make the silicon platforms sensitive to clinically relevant pressure levels in the intracranial fluid surrounding the brain. They also added a tiny temperature sensor and connected it to a wireless transmitter roughly the size of a postage stamp, implanted under the skin but on top of the skull.