Flexible piezoresistive sensors with high sensitivity and a large linear response range for cuffless blood pressure monitoring via pulse wave velocity

Cardiovascular disease, characterized by acute onset and high mortality rates, necessitates continuous daily monitoring of blood pressure (BP). Recently, advancements in flexible pressure sensing and intelligent wearable technology offer new solutions for non-invasive ambulatory BP monitoring. However, measuring BP with pressure sensors remain challenging due to the weak nature of skin pulse waves, making it difficult to obtain high-fidelity signals. This work introduced a piezoresistive sensor based on polydopamine and carbon nanotubes, which demonstrated high sensitivity (6.23 kPa −1 ), excellent linearity (R 2  = 0.996) across a broad pressure range (0–350 kPa), and maintained a stable electrical response after 10000 compression cycles. It featured a low detection limit (less than 100 Pa) and a rapid response time (100 ms), enabling the detection of pulse waves at multiple regions. Additionally, this study established a multi-parameter BP estimation model using the pulse wave velocity method, which significantly outperformed three simple models in terms of fitting accuracy. Concurrently, a dual-channel pulse wave measurement system was developed to estimate BP values, and its results were consistent with those from commercial sphygmomanometers. This work provided a simple, low-cost approach for the long-term monitoring of cardiovascular diseases, presenting a competitive alternative to current complex systems. Graphical abstract