According to SCMP, a tiny sensor the size of a sesame seed could revolutionize the monitoring and care of patients suffering from brain injuries or brain tumors.
This type of hydrogel-based wireless sensor, developed by Chinese scientists, is biodegradable and can be injected into the brain to measure temperature, pH, intracranial pressure, and blood flow with the assistance of an external ultrasound probe.
Tests have shown that it can perform these measurements with even greater accuracy than current sensors.
The researchers wrote in a paper published in the journal Nature on June 5: “Compared to current studies on wireless implanted sensors, our metagel sensor offers distinct advantages in terms of implant size, separation of multiple signals, and biodegradability.”
The sensor is the size of a sesame seed. (Photo: Huazhong University of Science and Technology)
Zang Jianfeng, the author and a professor at Huazhong University of Science and Technology, added: “The metagel ultrasound sensor that we invented can be injected using advanced acoustic metamaterials technology and is only 2×2×2 mm, which is equivalent to the size of a sesame seed.”
Furthermore, through the external ultrasound probe, it can wirelessly monitor changes in physiological parameters in the brain. When researchers tested their gel sensor in mice and pigs, they found that it remained stable in the brain for up to one month and completely biodegraded after four months.
The wireless design and biodegradability will ensure that patients undergoing treatment for cancer or brain injuries will no longer need to undergo additional surgeries for removal. The paper also mentioned that it would prevent the risk of infection associated with wired clinical probes typically used to transmit data through holes in the scalp.
Although the technology in the industry has gradually shifted towards wireless sensors, the challenges in clinical application still lie in sensor size, biocompatibility, and communication range.
According to the research team, this sensor is introduced into the intracranial space using a puncture needle. The metagel material then deforms in response to physiological changes in the brain’s environment, causing a shift in the peak frequency of the reflected ultrasound waves, which is then measured wirelessly using an external ultrasound probe to collect data.
The shape of the gel sensor consists of small holes or gas columns, allowing the external ultrasound probe to accurately capture the physiological environment within the brain.
The device can be inserted into the brain via a needle and then biodegrades. (Photo: Medical Xpress)
A gel sensor can independently measure a specific parameter such as temperature or pH based on the generated material and can accommodate multiple gels simultaneously to measure different parameters. The research team stated that gel sensors could be detected by an external ultrasound probe from over 10 cm away, “allowing for thorough detection of brain tissue.”
The researchers also tested the sensor in mice and pigs by injecting them alongside wired clinical sensors to compare measurement results. They found that “Metagel outperformed the probes in monitoring clinical intracranial pressure in terms of resolution and temporal accuracy.”
The gel sensors from the team started to biodegrade after five weeks; however, Zang mentioned that they could be specifically designed to function for a longer duration if necessary. He noted that as their work focuses on innovating medical devices using soft materials, the team would need to discuss practical applications with clinical doctors.
He shared: “Compared to existing commercial intracranial pressure sensors, our sensor can significantly reduce patient pain, and we also hope that our research can contribute to the lives and health of people.”
