Advances in graphene-assisted flexible substrate sensors for human motion monitoring

Graphene, a two-dimensional nanomaterial with exceptional properties, has emerged as a promising candidate for the development of flexible substrate sensors for human motion monitoring. This review comprehensively explores the recent advances in graphene-based sensors, focusing on their fabrication techniques, sensing mechanisms, and applications in detecting various physical and physiological parameters. The unique electrical, mechanical, and chemical properties of graphene, such as high carrier mobility, excellent mechanical strength, and large surface area, are discussed in detail. The review delves into the different synthesis methods of graphene and graphene oxide, as well as the techniques for integrating them onto flexible substrates. Graphene-based strain and pressure sensors, which exploit the piezoresistive and piezoelectric properties of graphene, are extensively examined, along with strategies for enhancing their sensitivity and performance. The application of these sensors in monitoring joint movements, respiration, and cardiovascular parameters is highlighted. Additionally, the review explores the potential of graphene-based electrochemical sensors for detecting electrophysiological signals and biochemical analytes, such as glucose and lactate. Finally, the challenges and future directions in the field of graphene-based flexible substrate sensors are discussed, emphasizing the need for further research to address issues related to scalability, reproducibility, and integration with wireless electronics.