In recent years, flexible pressure sensors have made significant progress in monitoring various physiological signals, such as blood pressure, pulse wave, blood glucose, and blood oxygen. Most flexible pressure sensors are mainly used for monitoring daily activities below 100 kPa. Although many sensors can achieve high sensitivity within a moderate pressure range, their performance often depends on the vertical compressibility of the pressure-sensitive layer. After compression, the sensitive layer structure will rapidly densify, leading to a rapid decrease in sensitivity to zero. However, in unrestricted scenarios, flexible sensors may also face extreme pressure conditions such as joint motion monitoring, plantar pressure monitoring, and tire pressure monitoring. Therefore, existing flexible pressure sensors still face challenges in maintaining high sensitivity within an ultra wide pressure detection range

 In response to existing challenges, Professor Wang Xuewen's research group led by Academician Huang Wei from Northwestern Polytechnical University has proposed a new type of pressure sensor based on strain effect, and the related results have been published in the journal Advanced Materials. Dr. Li Yue, a doctoral student from the Institute of Flexible Electronics, and Dr. Zhang Weijie from Xi'an Red Cross Hospital are the co first authors of this article, while Academician Huang Wei and Professor Wang Xuewen are co corresponding authors.

By adjusting the size and modulus differences of flexible ultra-thin conductive films and strain induced microstructures, a positive increase in sensitivity within an ultra wide pressure detection range has been achieved. The sensor exhibits stable positive resistance response within the pressure range of 45 Pa to 4.1 MPa; Meanwhile, unlike the classical piezoresistive effect structure, the sensitivity of the sensor increases from 5.22 MPa-1 to 70 MPa-1 with increasing pressure. This achievement breaks the constraint between high sensitivity and wide pressure detection range of flexible pressure sensors, achieving a synergistic improvement of sensitivity and pressure detection range, and providing new ideas for the design of wide pressure range flexible sensors.Based on the above performance advantages, the research team has applied this sensor in the fields of gait cycle feedback monitoring and contact pressure feature capture in knee replacement surgery, assisting doctors in quantitatively analyzing femoral and tibial pressure, balancing internal and external pressure distribution, and tracking femoral motion during knee replacement surgery. This technology provides more accurate data and analysis support for disease prevention, early diagnosis, and treatment through the innovation and application of flexible electronic technology. This research achievement is expected to accelerate the intelligent upgrade of medical equipment, promote the popularization of advanced digital medical technology, help achieve the goal of a healthy China, and further advance China's medical services towards intelligence, digitization, and networking.

Source: Sensor Expert Network