With the development of sensor technology, monitoring equipment has become more and more miniaturized, and smart wearable devices have gradually become a commonly used health management product in people’s daily life.

People have become accustomed to recording daily exercise, heart rate, sleep and other physical data through sports watches or smart bracelets. In addition to providing a basis for adjusting fitness plans, real-time monitoring of physical conditions is also of great help to the prevention, diagnosis and treatment of diseases. Therefore, the development of wearable devices has begun to shift from the health field to the medical field. This also means that the market has higher requirements for the accuracy of wearable device monitoring data.

At present, the method of measuring heart rate, blood pressure and other data for wearable devices such as smart bracelets and sports watches is mainly photoelectric method. Use an LED light source to emit a beam of light at the skin. When the heart contracts and pumps blood, the blood flow in the blood vessels is large and the proportion of oxygenated hemoglobin is high, and the blood tends to reflect red light and absorb green light; when the heart is diastolic, the absorption and reflection of light by the blood will change. The device receives the reflected light signal through the photoelectric receiving tube and converts it into an electrical signal. The periodic change of the signal is the same as the pulse. According to the received signal, the heart rate and blood pressure can be detected.

Wearable medical devices have more requirements on body data. In addition to heart rate and blood pressure, blood oxygen is also required, and the requirements for accuracy are also high. At present, the detection level of smart bracelets cannot meet the medical needs, and the bracelets/watches need to be properly worn for real-time monitoring of body data without light leakage. With the development of flexible Electronic materials, more and more researchers have begun to try to develop detection devices that directly fit the skin.

There have been many research results of flexible wearable electronic devices at home and abroad. For example, the skin-like sensor developed by American materials scientist John Rogers can be used for whole body temperature and pressure sensing. Chinese-American physicist Wang Zhonglin combines self-driven electronic systems with The electronic skin developed by the flexible wearable device, the fibrous implantable biosensor developed by the research team of Fudan University in my country, etc.

Recently, the research group of Professor Feng Xue from the School of Aeronautics and Astronautics of Tsinghua University and the Flexible Electronic Technology Research Center has made new achievements in flexible wearable medical devices. The research team used flexible ultra-thin photoelectric sensors and circuits to develop a monitoring system that can be naturally attached to the skin and continuously measure blood pressure and blood oxygen in real time. The data obtained by monitoring meets the requirements of medical testing. The findings were published in the National Science Review.

The flexible electronic system is developed on the basis of the smart bracelet photoelectric method to measure blood pressure, and integrates photoelectric devices into biocompatible materials to produce thin and light electronic products that can naturally fit with human skin. When measuring the blood pressure and blood oxygen data of the human body, the detection data will also be sent to smart terminals such as mobile phones through the Bluetooth chip in real time. According to the clinical trial, the blood pressure data measured by the flexible electronic system is very close to the detection result of the traditional cuff-type measurement method, and meets the medical-grade monitoring standard. This shows that the detection library of the flexible electronic system can be directly applied to clinical diagnosis and treatment.

The accuracy of the data depends on the relatively complete theoretical model of the relationship between blood pressure and measurement parameters established by the research team. At the same time, the researchers also considered the interference of the device deformation on the measurement.

The biggest problem with mobile individualized medical testing brought by wearable medical devices is that the accuracy of testing data is far from that of professional testing instruments in hospitals. The new research results of Tsinghua University have made a huge breakthrough in detection accuracy, and have great reference significance for the research of other wearable medical devices. When this new blood pressure monitoring method is put into practice, it will greatly reduce medical costs and set off a revolution in the field of medical testing.

Then, for the medical instrument industry, when the traditional detectors are gradually replaced, the manufacturers of these instruments will face huge challenges.

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