A New Catechol Biosensor Immobilized Polyphenol Oxidase by Combining Electropolymerization and Cross-Linking Process

Abstract

A highly stable and effective catechol biosensor was prepared by immobilizing polyphenol oxidase (PPO) into polyaniline (PANI) film by using the direct electropolymerization (one-step) process in conjunction with cross-linking with glutaraldehyde. The results of electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) confirmed that the immobilization of PPO was successful. The biosensor has a fast response to catechol (10 s) with a linear range of 1.0–100 µM and a detection limit of 0.01 µM. The maximum response current (I _max) and the Michaelis-Menten constant (k' _m) were found to be 7.94 µA and 81.32 µM, respectively. The activation energy (E _a) of the PPO catalytic reaction was 16.5 kJ/mol. The biosensor exhibited good stability by retaining 80% of its original activity when stored in a dry state at 4°C for up to 5 months.

Keywords:

• Catechol
• cross-linking process
• one-step process
• polymer synthesis
• polyphenol oxidase

Acknowledgment

This project was supported by National Science Foundation of China (No. 20873119). A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions. Part of the data was from the Testing Center of Yangzhou University.

Notes

^a PBS = phosphate buffer solution. ^b β-CD = β-cyclodextrin.