Department of Chemical Science and Technologies, University of Rome Tor Vergata, Via della Ricerca Scientifica 1, 00133, Rome, Italy.
Department of Civil Engineering and Informatics, University of Rome Tor Vergata, Via del Politecnico,1, 00133, Rome, Italy.
Talanta. 2021 Jan 15;222:121502. doi: 10.1016/j.talanta.2020.121502. Epub 2020 Aug 9.
In the last decade, wearable sensors have gained a key role on biomedical research field for reliable health state monitoring. A wide plethora of physics marker sensors is already commercially available, including activity tracker, heart rate devices, and fitness smartwatch. On the contrary, wearable and epidermal sensors for chemical biomarker monitoring in several biofluids are not ready yet. Herein, we report a wireless and flexible epidermal device for pH monitoring in sweat, fabricated by encompassing a screen-printed potentiometric sensor, an integrated circuit, and antenna embedded onto the same Kapton substrate. An iridium oxide film was electrodeposited onto the graphite working electrode providing the pH sensitive layer, while the integrated circuit board allows for data acquisition and storing. Furthermore, a radio frequency identification antenna surrounding the entire system enables data transmission to an external reader up to nearly 2 m in the most favourable case. The potentiometric sensor was firstly characterised by cyclic voltammetry experiments, then the iridium oxide electrodeposition procedure was optimised. Next, the sensor was tested toward pH detection in buffer solutions with a near-Nernstian response equal to -0.079 ± 0.002 V for unit of pH. Interference studies of common sweat ions, including Na, K and Cl, showed any influence on the pH sensor response. Finally, the integrated epidermal device was tested for real-time on-body pH sweat monitoring during a running activity. Data recorded for a running subject were wireless transmitted to an external receiver, showing a pH value close to 5.5, in agreement with value obtained by pH-meter reference measurement.
在过去的十年中，可穿戴传感器在生物医学研究领域中发挥了重要作用，可用于可靠的健康状态监测。已经有大量的物理标记传感器可用于商业用途，包括活动追踪器、心率设备和健身智能手表。相比之下，用于监测几种生物流体中化学生物标志物的可穿戴和表皮传感器还没有准备好。在这里，我们报告了一种用于汗液中 pH 监测的无线灵活表皮设备，该设备通过将印刷电极传感器、集成电路和天线嵌入到同一张 Kapton 基底上来制造。将氧化铱薄膜电沉积到石墨工作电极上，提供 pH 敏感层，而集成电路板允许进行数据采集和存储。此外，一个环绕整个系统的射频识别天线允许在最有利的情况下将数据传输到外部读取器，距离可达近 2 米。首先通过循环伏安法实验对电位传感器进行了表征，然后优化了氧化铱的电沉积过程。接下来，对传感器进行了缓冲溶液中 pH 检测测试，响应接近于 -0.079 ± 0.002 V/单位 pH 的近 Nernst 响应。对常见汗液离子（包括 Na、K 和 Cl）的干扰研究表明，它们对 pH 传感器响应没有任何影响。最后，对集成的表皮设备进行了实时的跑步活动中汗液 pH 监测测试。记录的跑步者数据被无线传输到外部接收器，显示 pH 值接近 5.5，与 pH 计参考测量值一致。
