Department of Mechanical and Materials Engineering, Florida International University, Miami, Florida 33174, United States.
Department of Electrical and Computer Engineering, Florida International University, Miami, Florida 33174, United States.
ACS Appl Mater Interfaces. 2024 Nov 27;16(47):65402-65413. doi: 10.1021/acsami.4c17710. Epub 2024 Nov 12.
Wearable, flexible piezoresistive pressure sensors have garnered substantial interest due to their diverse applications in fields such as electronic skin, robotic limbs, and cardiovascular monitoring. Among these applications, arterial full pulse waveform monitoring stands out as a critical area of research. The emergence of piezoresistive pressure sensors as a prominent tool for capturing pulse waveforms has led to extensive investigations. However, the lack of a linear response while achieving high sensitivity, limited compactness of signal collection systems, and scaling issues are a few potential causes of the gap between research advances and technology market readiness. Here, we present a scalable dual piezoresistive sensor that uses two complementary resistance-changing mechanisms to balance the trade-off between linear response and high sensitivity. This synergic design enables excellent sensitivity of 8.4 kPa and near linear pressure response. It boasts a fast response time of 95/145 ms for loading and unloading at a pressure of 10.1 kPa. The durability tests, encompassing nearly 5000 two-stage compression cycles, validate the reliable performance of the sensor, even after prolonged use. Leveraging these performance metrics, we developed a high-resolution and compact signal collection device capable of accurately detecting the three distinct peaks associated with the full pulse waveform, including the systolic and reflected diastolic peaks. Moreover, the signal acquisition system incorporates a photoplethysmography sensor, which, when paired with the dual piezoresistive sensor, offers new insights into localized vascular health monitoring. The unique feature of our approach is its ability to perform localized vascular monitoring using multiple sensors placed on different veins. The simultaneous detection of forward- and backward-going pulse waves at the body extremities allows for a comprehensive evaluation of localized vascular health, which is not achievable with a single sensor. Finally, the comparison of wrist pulse waveforms between the compact signal collection device and a standard sourcemeter (such as the Keithley 2460) confirmed that the wearable sensing system is on par with conventional sourcemeters in terms of capturing the typical details of the full pulse waveform (i.e., systolic peak, dicrotic notch, and diastolic peak). This validation underscores the reliability and effectiveness of the developed wearable sensing system for practical and continuous pulse waveform monitoring.
可穿戴、柔性压阻压力传感器因其在电子皮肤、机器肢体和心血管监测等领域的广泛应用而备受关注。在这些应用中，动脉全脉搏波监测是一个关键的研究领域。压阻压力传感器作为捕捉脉搏波的重要工具，已经得到了广泛的研究。然而，在实现高灵敏度的同时缺乏线性响应、信号采集系统紧凑性有限以及可扩展性问题，是研究进展与技术市场准备之间存在差距的几个潜在原因。在这里，我们提出了一种可扩展的双压阻传感器，它使用两种互补的电阻变化机制来平衡线性响应和高灵敏度之间的权衡。这种协同设计使传感器具有出色的灵敏度为 8.4kPa 和近乎线性的压力响应。在 10.1kPa 的压力下，加载和卸载的响应时间分别为 95/145ms。接近 5000 次两阶段压缩循环的耐久性测试验证了传感器的可靠性能，即使经过长时间使用也是如此。利用这些性能指标，我们开发了一种高分辨率且紧凑的信号采集设备，能够准确检测到全脉搏波的三个不同峰值，包括收缩峰和反射性舒张峰。此外，信号采集系统结合了光电容积脉搏波传感器，当与双压阻传感器结合使用时，可以提供新的局部血管健康监测见解。我们方法的独特之处在于它能够使用放置在不同静脉上的多个传感器进行局部血管监测。同时检测身体四肢的正向和反向脉搏波，可以全面评估局部血管健康，这是单个传感器无法实现的。最后，将紧凑信号采集设备和标准源表（如 Keithley 2460）之间的腕部脉搏波波形进行比较，证实了可穿戴传感系统在捕捉全脉搏波波形的典型细节（即收缩峰、重搏切迹和舒张峰）方面与传统源表相当。这种验证突出了所开发的可穿戴传感系统在实际和连续脉搏波监测方面的可靠性和有效性。
