Free-standing conductive hydrogel electrode for potentiometric glucose sensing.

Shogo Himori,Toshiya Sakata

doi:10.1039/d1ra08956k

Abstract

Flexible conductive polymer hydrogels are attracting attention as an electrode material. Electrochemical biosensors with conductive polymer hydrogels have been developed because they have some advantages such as biocompatibility, high conductivity, 3D nanostructure, solvated surface, and enlarged interface. Conductive polymer hydrogels bearing receptor molecules such as enzymes in its 3D nanostructure enable the detection of target analytes with high sensitivity. However, because such hydrogels are fragile, they cannot stand on their own and a supporting substrate is required to fabricate them. This means that the loss of mechanical toughness is detrimental for their application to flexible biosensors. In this study, we have proposed a free-standing conductive hydrogel electrode with no coating on a substrate, which is composed of polyaniline with phenyl boronic acid including polyvinyl alcohol, for potentiometric glucose sensing. In addition, its electrical responsivity to glucose has been confirmed by investigating its mechanical properties at various glucose concentrations, considering the hydrogel compositions.

Highlights

Electrochemical biosensors are attractive tools for measuring biomarkers in humans for medical diagnosis
Considering the adhesiveness of polyvinyl alcohol (PVA) in the P(ANI-amino phenylboronic acid (APBA))-PVA-based FSC hydrogel, it was connected to the platinum wire as a gate electrode by physical bonding
The peaks at 2920 and 1020 cmÀ1 were derived from the vibrations of C–H and C–O of PVA, respectively,[30] and the peak of 690 cmÀ1 was attributed to the O–B–O bending of APBA.[31]

Summary

Introduction

Electrochemical biosensors are attractive tools for measuring biomarkers in humans for medical diagnosis. Polyaniline (PANI), which is used as a conductive polymer, shows the expected electrochemical properties in polyvinyl alcohol (PVA) as an insulative matrix.[19]. In this synthetic route, amino phenylboronic acid (APBA) is copolymerized with ANI [P(ANI-APBA)] and used as a cross-linker with the PVA matrix on the basis of the speci c binding between PBA and diol molecules such as PVA (Fig. 1A). An FSC hydrogel electrode was fabricated from ANI, APBA, and PVA in a one-step facile process, and its electrochemical responsivity toward glucose was investigated using a FET potential measurement system. This study can contribute to the utilization of conductive hydrogel biosensors with high mechanical toughness

Chemicals

Hydrogel electrode fabrication

Electrochemical measurement

Force curve measurement by AFM

Results and discussion

Conclusions