Reduced Graphene Oxide-based Flexible Pressure Sensor for Biomedical Applications

Pressure sensing is a crucial technique for various biomed- ical applications, where it can provide valuable information about the health and function of different organs and systems. This paper reports the development of a novel integrated pressure sensor based on mod- ified rGO, a graphene-derivative material with enhanced piezoresistive properties. The sensor is fabricated on a flexible PCB substrate and conditioned by a smart current-based Wheatstone bridge circuit, which enables high sensitivity, wide detection range, fast response and re- covery, and good stability under cyclic loading. The sensor achieves a measured sensitivity of 0.281 kPa-1 (at 0.5 kPa load). A mechanical sys- tem is also designed to adapt the sensor to different anatomical sites and to improve its elastic recovery. The sensor’s functionality is initially demonstrated through its response to controlled mechanical stimula- tion, achieving a signal-to-noise ratio (SNR) of 25 dB. Subsequently, in a practical application, physiological signals from the carotid and femoral arteries of volunteers were acquired. The system effectively captured the pulse waveforms with high fidelity and accuracy (23.5 dB SNR) and measured the pulse transit time, an important parameter for estimating the pulse wave velocity and arterial stiffness. The sensor is not limited to this specific application and can be easily extended to other domains where pressure sensing is required. In conclusion, it offers a low-cost, flexible, and user-friendly solution for non-invasive biomedical monitoring and diagnosis.