Chinese researchers develop injectable biodegradable gel-based sensors

A Chinese research team has created a mini injectable ultrasonic sensor for wireless monitoring of intracranial signals, thereby providing an option which goes beyond the limitations of current clinical instruments.

Physiological data are indicators used to determine the physiological state of the human body, which can help doctors diagnose, treat and detect diseases. Obtaining accurate physiological data concerning the human body in a safe and stable manner has long been a major focus in the medical monitoring field.

The study, published recently in the journal Nature, noted that current wired clinical instruments that use percutaneous leads are susceptible to causing infection and potential surgical complications, while patient mobility is also affected.

Wireless implantable devices offer greater operational freedom but were previously subject to problems such as limited detection range, poor degradation and difficulty in terms of size reduction in the human body.

The research team, led by professor Zang Jianfeng from the Huazhong University of Science and Technology, developed an injectable, bioresorbable and wireless metastructured hydrogel sensor for ultrasonic monitoring of intracranial signals.

According to the study, the sensors are cubes that are 8 cubic millimeters in size, and they are made from biodegradable and stimulus-responsive hydrogels and periodically aligned air columns with a specific acoustic reflection spectrum.

Implanted into intracranial space with a puncture needle, the devices can deform in response to physiological environmental changes, resulting in peak frequency shifts of reflected ultrasound waves that can be wirelessly measured by an external ultrasound probe.

Various categories of physiological data such as intracranial pressure, temperature, pH levels and blood flow velocity can therefore be obtained.

Notably, the invention is made of biodegradable polymer materials, which will degrade in the body after about one month, without having to be removed, reducing both pain and the risk of infection.

In addition, the research team has put forward an innovative algorithm that can efficiently separate the coupling effects of pressure, temperature, pH levels and other factors by simultaneously analyzing the frequency change data of multiple sensors, so as to achieve comprehensive perception of complex physiological environments.

The research team noted that these devices provide huge advantages in reducing energy consumption and having no thermal effect. In the future, they can also be applied to other parts of the human body, promising to deliver a new technology pattern for clinical intelligent diagnosis and treatment.