Such implants could be used to monitor patients with traumatic brain injuries, but the researchers believe they can build similar absorbable sensors to monitor activity in organ systems throughout the body.
"Electronic devices and their biomedical applications are advancing rapidly," said Rory Murphy, MD, a neurosurgery resident at Washington University School of Medicine. "But 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."
When patients with traumatic brain injuries arrive at a hospital, doctors must be able to accurately measure intracranial pressure in the brain and inside the skull because an increase in pressure can lead to further brain injury, and there is no way to reliably estimate pressure levels from brain scans or clinical features in patients.
"However, the devices commonly used today are based on technology from the 1980s," Dr Murphy explained. "They're large, they're unwieldy, and they have wires that connect to monitors in the intensive care unit. They give accurate readings, and they help, but there are ways to make them better."
The team’s devices are smaller than the tip of a pencil and are made mainly of polylactic-co-glycolic acid (PLGA) and silicone. They can transmit accurate pressure and temperature readings, as well as other information.
John Rogers, professor of materials science and engineering at the University of Illinois, explained: "With advanced materials and device designs, we demonstrated that it is possible to create electronic implants that offer high performance and clinically relevant operation in hardware that completely resorbs into the body after the relevant functions are no longer needed."
Having shown that the sensors are accurate and that they dissolve in a saline solution and then in the brains of laboratory rats, the researchers now are planning to test the technology in patients.