When a patient sustains a traumatic brain injury, doctors need to monitor pressure on the brain both inside and outside of the skull to prevent further brain injury. Though there are currently monitors that are up to the job, they are large and unwieldy. Now, researchers have developed a wireless brain sensor that is ultimately absorbed by the body, eliminating the need for removal surgery.
The team of researchers - from the Washington University School of Medicine in St. Louis, MO, and the University of Illinois at Urbana-Champaign - say that their implants could be used to monitor patients with traumatic brain injury (TBI), but similar sensors could be used to monitor organ activity in the rest of the body.
They publish the results of their latest study in the journal Nature.
In the US each year, around 50,000 people die of TBI. According to the Centers for Disease Control and Prevention (CDC), a TBI is caused by a blow or bump to the head that disrupts the normal function of the brain.
Though not all blows to the head result in a TBI, the severity of a TBI may range from mild to severe, including an extended period of unconsciousness or amnesia after injury.
Because there is no way to reliably estimate brain pressure levels from either brain scans or clinical features, when a patient is admitted to the hospital with a TBI, doctors must use devices that "are based on technology from the 1980s," according to Dr. Rory K. J. Murphy, study author from Washington University School of Medicine.
"They're large, they're unwieldy, and they have wires that connect to monitors in the intensive care unit," he says. "They give accurate readings, and they help, but there are ways to make them better."
'Hardware completely resorbs into the body when no longer needed'
Although the biomedical applications of electronic devices are moving forward, Dr. Murphy notes that "a major hurdle has been that implants in the body often trigger an immune response," causing problems for patients.
To bypass this issue, Dr. Murphy and colleagues worked together to develop devices made of polylactic-co-glycolic acid (PLGA) and silicone, which can transmit pressure, temperature readings and other information accurately.
The team first tested the sensors in saline solution baths, which caused them to dissolve in a few days. Their next step was to test the devices in laboratory rats' brains.
After successful tests, in which the team demonstrated that the sensors are accurate and fully dissolvable in the rat brains, the researchers now plan to test their sensors in human patients.
Commenting on their new device, Prof. John A. Rogers, from the University of Illinois, says:
"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."
He adds that their device "has great potential in many areas of clinical care."
Device proven to operate continuously for 3 days
They key benefit of their new device is its solubility. For patients, this means "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," explains Dr. Murphy.
Furthermore, by not requiring surgery for their removal, the devices decrease risk of infection and other complications.
Because the researchers have proven that their devices can operate continuously for 3 days, they say these timeframes are sufficient for clinical use, given that patients with TBIs often need to be monitored for several days after injury.
Regarding further clinical uses, Dr. Murphy says that in patients with TBIs whose brain pressure cannot be reduced adequately, surgery often needs to be performed. Their new devices could be placed in the brain at multiple locations during surgery to further monitor the patient.
He says of their overall goal:
"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."
"And then," adds Dr. Murphy, "after the critical period that you actually want to monitor, it will dissolve away and disappear."
Medical News Today recently reported on nanotechnology in development that could be capable of detecting infection on implants before symptoms appear.