Chinese researchers have developed a biodegradable and wireless brain sensor the size of a sesame seed that could potentially change the way brain conditions are monitored in patients with head injuries or tumors.
The conventional method used to measure intracranial pressure, temperature and other barometers of brain health is to insert a wired sensor into the brain. Implantation and removal of the device requires surgery, and holes left in the skin during monitoring increase the risk of infection.
To solve these problems, researchers from Huazhong University of Science and Technology in Wuhan, Hubei province, along with those from the city’s Tong Ji Hospital and Nanyang Technological University in Singapore, created a cube-shaped wireless sensor measuring 2 millimeters on each side.
A tiny tube can be injected under the skull with a needle and operated with an external ultrasound probe, eliminating the need for invasive surgery and preventing infections.
Because the implant is based on a biodegradable material called a hydrogel, it can eventually dissolve into harmless components.
The researchers tested the sensor on rats and pigs and found it could perform as well or even better than conventional wire sensors in measuring intracranial pressure and temperature. It remained stable for three to four weeks and decomposed into harmless components after 18 weeks.
The results of their research were published by the international scientific journal Nature on June 5.
Zang Jianfeng, a professor at the university’s School of Integrated Circuits who led the research, said the invention stems from years of research into hydrogel properties and flexible acoustic technology.
At the heart of their innovation is making changes to the composition of the degradable hydrogel so that it presents a periodically aligned structure of the air column. The material deforms in response to changes in its environment, which can be detected using an external ultrasonic probe.
“So far, we have done a lot of experiments, including animal tests, to check its safety and biodegradability, and the results are promising,” he said.
Zang added that the team can produce sensors of different sizes or shapes based on demand.
“It could be a 1-millimeter cube or a few centimeters on each side, or a thin slice,” he said.
He said the team’s research is close to clinical application, but more efforts are needed to deepen collaboration with doctors, test the sensor’s effects in human bodies after rigorous ethical and technological review, and explore ways to use the technology on an industrial scale.
The size of the global market for traditional wire sensors, which primarily serve patients with brain tumors or traumatic injuries, is about $390 billion.
