Enhanced Electrochemical Characteristics of the Glucose Oxidase Bioelectrode Constructed by Carboxyl-Functionalized Mesoporous Carbon.

Chuhan Lv,Xingyu Zhu,Shuangfei Li,Liangxu Liu,Xuewei Yang

doi:10.3390/s20123365

Abstract

This research revealed the effect of carboxyl-functionalization on the mesoporous carbon (MC)-fixed glucose oxidase (GOx) for promoting the properties of bioelectrodes. It showed that the oxidation time, temperature and concentration, can significantly affect MC carboxylation. The condition of 2 M ammonium persulfate, 50 °C and 24 h was applied in the study for the successful addition of carboxyl groups to MC, analyzed by FTIR. The nitrogen adsorption isotherms, and X-ray diffraction analysis showed that the carboxylation process slightly changed the physical properties of MC and that the specific surface area and pore size were all well-maintained in MC-COOH. Electrochemical characteristics analysis showed that Nafion/GOx/MC-COOH presented better electrocatalytic activity with greater peak current intensity (1.13-fold of oxidation peak current and 4.98-fold of reduction peak current) compared to Nafion/GOx/MC. Anodic charge-transfer coefficients (α) of GOx/MC-COOH increased to 0.77, implying the favored anodic reaction. Furthermore, the GOx immobilization and enzyme activity in MC-COOH increased 140.72% and 252.74%, leading to the enhanced electroactive GOx surface coverage of Nafion/GOx/MC-COOH electrode (22.92% higher, 1.29 × 10−8 mol cm−2) than the control electrode. Results showed that carboxyl functionalization could increase the amount and activity of immobilized GOx, thereby improving the electrode properties.

Highlights

Fuel cells, which convert chemical fuels into electricity, have been considered as a renewable power source for electronic equipment
The results showed that the carboxylation various reaction conditions, includingshown different oxidation temperatures, APS
When the oxidative temperature increased from 30 to 60 °C and the oxidative time increased from 6 h to 48 h, the ability and total pore volume of the mesoporous carbon (MC)-COOH samples compared to the MC samples was further evidence of the active loading of glucose oxidase (GOx) inside the mesopores because of carboxylation

Summary

Introduction

Fuel cells, which convert chemical fuels into electricity, have been considered as a renewable power source for electronic equipment. Due to the minimal risk of false-positive responses, enzymes are the most promising bio-receptors used in bio-sensors [1]. Unlike noble metal catalysts which are valuable and rare, enzymes as a biological catalyst possess renewable and abundant sources [2]. Immobilizing redox enzymes (such as glucose oxidase (GOx)) onto electrode material surfaces, has become a keen interest in biofuel cell and sensor development. Anahita Karimi et al outlined the advantages and limitations of functionalized graphene and graphene-based nanocomposite immobilized enzymes, and proved the possibility of the development of graphene-based enzyme biofuel cells [3].

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Conclusion