A CNT-PDMS wearable device for simultaneous measurement of wrist pulse pressure and cardiac electrical activity

Li Wang; Wenkun Dou; Jun Chen; Kechao Lu; Feng Zhang; Mohammed Abdulaziz; Weiguang Su; Anqing Li; Chonghai Xu; Yu Sun

doi:10.1016/j.msec.2020.111345

A CNT-PDMS wearable device for simultaneous measurement of wrist pulse pressure and cardiac electrical activity

Mater Sci Eng C Mater Biol Appl. 2020 Dec:117:111345. doi: 10.1016/j.msec.2020.111345. Epub 2020 Aug 11.

Authors

Li Wang¹, Wenkun Dou², Jun Chen³, Kechao Lu¹, Feng Zhang¹, Mohammed Abdulaziz⁴, Weiguang Su¹, Anqing Li¹, Chonghai Xu⁵, Yu Sun⁶

Affiliations

¹ Advanced Micro and Nanoinstruments Center (AMNC), School of Mechanical & Automotive Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong 250353, China.
² Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON M5S 3G8, Canada.
³ Advanced Micro and Nanoinstruments Center (AMNC), School of Mechanical & Automotive Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong 250353, China. Electronic address: chenjun@qlu.edu.cn.
⁴ Department of Mechanical and Process Engineering, University of Duisburg Essen, Forsthausweg 247057, Germany.
⁵ Advanced Micro and Nanoinstruments Center (AMNC), School of Mechanical & Automotive Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong 250353, China. Electronic address: xch@qlu.edu.cn.
⁶ Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON M5S 3G8, Canada. Electronic address: sun@mie.utoronto.ca.

PMID: 32919692
DOI: 10.1016/j.msec.2020.111345

Abstract

Simultaneous measurement of multi-physiological signals can provide effective diagnosis and therapeutic assessment of diseases. This paper reports a carbon nanotube (CNT) - Polydimethylsiloxane (PDMS) - based wearable device with piezo-resistive and voltage-sensing capabilities for simultaneously capturing wrist pulse pressure and cardiac electrical signal. The layout design of sensing elements in the device was guided by analyzing strain distribution and electric field distribution for minimizing the interference between wrist pulse and cardiac electric activity during measurement. Each device was preconditioned under the strain of 20% until the resistance change of the device reached equilibrium. After preconditioning, the relationship between the resistance change and the pressure was calibrated, which determined the device sensitivity to be 0.01 Pa^-1 and the linear pressure range of the device to be 0.4 kPa to 14.0 kPa. Mechanisms of CNT-PDMS for sensing strain signal and electrical pulse signal were explored by scanning electron microscopy (SEM) imaging and equivalent circuit modeling. The device was applied to monitor the wrist pulse and ECG signals of volunteers during the recovering process after physical exercises.

Keywords: Carbon nanotube (CNT); Electrocardiograph (ECG); Polydimethylsiloxane (PDMS); Wearable device; Wrist pulse pressure.

MeSH terms

Blood Pressure
Dimethylpolysiloxanes
Humans
Nanotubes, Carbon*
Wearable Electronic Devices*
Wrist

Substances

Dimethylpolysiloxanes
Nanotubes, Carbon