Advanced Design of Next-Generation Piezoresistive Sensors with Tailored Microstructures for Digital Healthcare

The piezoresistive effect serves as a key mechanical sensing mechanism extensively utilized across diverse sensing applications. Piezoresistive stress-strain sensors stand out due to their straightforward design, high sensitivity, low energy requirements, and versatile functionality, making them particularly promising for the advancement of wearable flexible electronics. These sensors are poised to become a foundational technology in the evolution of digital healthcare. In this Perspective, we comprehensively summarize recent advancements and innovative uses of flexible piezoresistive sensing technologies. First, we theoretically characterize the charge transport models of the piezoresistive effect in flexible substrates, including the quantum tunneling effect, microcrack propagation mechanism, and contact resistance theory. We then comprehensively elucidate the structure-performance relationships of five major material systems: micro/nanoarchitectured materials, flexible conductive aerogels, biocompatible soft hydrogels, smart responsive fabrics, and conductive paper-based devices. Furthermore, we highlight the breakthrough applications of this technology in digital healthcare, exemplified by high-precision wearable physiological signal monitoring systems, intelligent prosthetic tactile feedback devices, and advanced postoperative rehabilitation assessment platforms. Finally, we discuss future directions, emphasizing the integration of machine learning to enhance flexible sensing systems for personalized precision medicine and remote intelligent healthcare solutions.