Wireless, dissolvable sensors to monitor brain

Scientists have developed wireless sensors that monitor pressure and temperature inside the brain and then are absorbed by the body, negating the need for surgery to remove the devices.
The implants potentially could be used to monitor patients with traumatic brain injuries. The researchers believe they can build similar absorbable sensors to monitor activity in organ systems throughout the body.
"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," said Rory K J Murphy, a neurosurgery resident at Washington University School of Medicine and Barnes-Jewish Hospital in St Louis.

"Plus, using resorbable devices negates the need for surgery to retrieve them, which further lessens the risk of infection and further complications," he said.
About 50,000 people die of traumatic brain injury annually in the US, researchers said.
When patients with such injuries arrive in the 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. 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," Murphy said.

The new sensors are made mainly of polylactic-co-glycolic acid (PLGA) and silicone, and they can transmit accurate pressure and temperature readings, as well as other information.
"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," John A Rogers, a professor of materials science and engineering at the University of Illinois.
The researchers tested the sensors in baths of saline solution that caused them to dissolve after a few days. Next, they tested the devices in the brains of laboratory rats.

Having shown that the sensors are accurate and that they dissolve in the solution and in the brains of rats, the researchers now are planning to test the technology in patients.
The findings were published in the journal Nature.