Towards Real-Time Blood Pressure Monitoring via High-Fidelity Iontronic Tonometric Sensors with High Sensitivity and Large Dynamic Ranges.
Qingzhou WanQian ChenMark A FreithalerSridhar Reddy VelagalaYihan LiuAlbert C ToAman MahajanRamakrishna MukkamalaFeng XiongPublished in: Advanced healthcare materials (2023)
Continuous, non-invasive blood pressure (CNIBP) monitoring provides valuable hemodynamic information that renders detection of the early onset of cardiovascular diseases. Wearable mechano-electric pressure sensors that mount on the skin are promising candidates for monitoring continuous blood pressure (BP) pulse waveforms due to their excellent conformability, simple sensing mechanisms, and convenient signal acquisition. However, it is challenging to acquire high-fidelity BP pulse waveforms since it requires highly sensitive sensors (sensitivity larger than 4 × 10 -5 kPa -1 ) that respond linearly with pressure change over a large dynamic range, covering the typical BP range (5 to 25 kPa). Here, we introduce a high-fidelity, iontronic-based tonometric sensor (ITS) with high sensitivity (4.82 kPa -1 ), good linearity (R 2 > 0.995), and a large dynamic range (up to 180% output change) over a broad working range (0 to 38 kPa). Additionally, our ITS demonstrates a low limit of detection at 40 Pa, a fast load response time (35 ms) and release time (35 ms), as well as a stable response over 5000 load/release cycles, paving ways for potential applications in human-interface interaction, electronic skins, and robotic haptics. We further explore the application of our ITS in monitoring real-time, beat-to-beat BP by measuring the brachial and radial pulse waveforms. Our work provides a rational design of a wearable pressure sensor with high sensitivity, good linearity, and a large dynamic range for real-time CNIBP monitoring. This article is protected by copyright. All rights reserved.