Stabilization of Bilirubin Oxidase in a Biogel Matrix for High-performance Gas Diffusion Electrodes

31 March 2020, Version 1
This content is a preprint and has not undergone peer review at the time of posting.

Abstract

Enzyme immobilization on solid conducting surfaces faces some challenges for practical applications in technologies such as biosensors and biofuel cells. Short-term stability, poor electrochemical performance, and enzyme inhibition are some issues that remain unsolved. Here, we propose a simple methodology for bilirubin oxidase (BOD) immobilization on carbon-based gas-diffusion electrodes for a four-electron electrochemical oxygen reduction reaction (ORR). The enzyme is incorporated into a Nafion® polymeric matrix and cross-linked with glutaraldehyde by a one-pot reaction in a buffered solution, producing a stable BOD-based biogel. The biogel prevents the formation of enzyme aggregates, producing a homogeneous bioelectrode surface, and allows access to the direct electron-transfer mechanism of multicopper centers buried in the enzyme. A biocatalytic reduction current of -1.52 ± 0.24 mA cm-2 at 0.19 ± 0.06 V was observed under gas-diffusion conditions. Additionally, the bioelectrode showed an unprecedented long-term stability under continuous operation combined with satisfactory catalytic current without redox mediator, demonstrating that the BOD-based biogel provides a suitable microenvironment for long-term enzymatic activity involving a bio-three-phase interfacial reaction. Therefore, the present study contributes new insights into enzyme immobilization to overcome the critical short-term stability issue of enzyme-based electrochemical devices for practical applications.

Keywords

Bilirubin oxidase
gas-diffusion electrode
enzyme immobilization
Oxygen reduction reaction
Direct electron transfer

Comments

Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.