Fabrication of Stretchable Copper Coated Carbon Nanotube Conductor for Non-Enzymatic Glucose Detection Electrode with Low Detection Limit and Selectivity.

Dawei Jiang,Zhongsheng Liu,Jianhua Qiu,Jianning Ding,Yu Zhang,Kanzan Inoue,Kunkun Wu,Zunfeng Liu,Raquel Ovalle-Robles,Linlin Mou,Ningyi Yuan,Yi Huang

doi:10.3390/polym10040375

Abstract

The increasing demand for wearable glucose sensing has stimulated growing interest in stretchable electrodes. The development of the electrode materials having large stretchability, low detection limit, and good selectivity is the key component for constructing high performance wearable glucose sensors. In this work, we presented fabrication of stretchable conductor based on the copper coated carbon nanotube sheath-core fiber, and its application as non-enzymatic electrode for glucose detection with high stretchability, low detection limit, and selectivity. The sheath-core fiber was fabricated by coating copper coated carbon nanotube on a pre-stretched rubber fiber core followed by release of pre-stretch, which had a hierarchically buckled structure. It showed a small resistance change as low as 27% as strain increasing from 0% to 500% strain, and a low resistance of 0.4 Ω·cm−1 at strain of 500%. This electrode showed linear glucose concentration detection in the range between 0.05 mM and 5 mM and good selectivity against sucrose, lactic acid, uric acid, acrylic acid in phosphate buffer saline solution, and showed stable signal in high salt concentration. The limit of detection (LOD) was 0.05 mM, for the range of 0.05–5 mM, the sensitivity is 46 mA·M−1. This electrode can withstand large strain of up to 60% with negligible influence on its performance.

Highlights

Stretchable conductors having stable resistance and high conductivity are key components for wearable electronics [1,2,3,4,5,6]
The CNTS used in this work was drawn from spinnable carbon nanotube forest (~6 walls, ~10 nm in diameter, and ~350 μm high) grown by chemical vapor deposition (CVD) method
The CNTS were drawn from a CNT forest which was grown by using a CVD method, and the carbon nanotube bundles were aligned in the drawing direction of the CNTS

Summary

Introduction

Stretchable conductors having stable resistance and high conductivity are key components for wearable electronics [1,2,3,4,5,6]. An efficient way to fabricate stretchable conductors is to use a conducting layer with buckled structure. Such a structure is prepared by coating conductive layer over a pre-stretched elastomeric polymer substrates followed by relax of the prestrain [7,8,9,10,11,12]. Polymers 2018, 10, 375 surface layer fattens without broken and kept resistance constant. The generally used material for the surface conducting layer is metal or semiconductor film, carbon nanotubes, graphene, or conducting polymer fibers. One of the limitations of using metal film is that the buckled metal film based stretchable conductor can only withstand very limited stain range (e.g., 10% for gold film coated on PDMS) [13]

Methods

Results

Conclusion