Elucidating Film Loss and the Role of Hydrogen Bonding of Adsorbed Redox Enzymes by Electrochemical Quartz Crystal Microbalance Analysis

Vivek M. Badiani, Samuel J. Cobb, Andreas Wagner, Ana Rita Oliveira, Sonia Zacarias, Ines A.C. Pereira, Erwin Reisner

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)

Abstract

The immobilization of redox enzymes on electrodes enables the efficient and selective electrocatalysis of useful reactions such as the reversible interconversion of dihydrogen (H2) to protons (H+) and formate to carbon dioxide (CO2) with hydrogenase (H2ase) and formate dehydrogenase (FDH), respectively. However, their immobilization on electrodes to produce electroactive protein films for direct electron transfer (DET) at the protein-electrode interface is not well understood, and the reasons for their activity loss remain vague, limiting their performance often to hour timescales. Here, we report the immobilization of [NiFeSe]-H2ase and [W]-FDH from Desulfovibrio vulgaris Hildenborough on a range of charged and neutral self-assembled monolayer (SAM)-modified gold electrodes with varying hydrogen bond (H-bond) donor capabilities. The key factors dominating the activity and stability of the immobilized enzymes are determined using protein film voltammetry (PFV), chronoamperometry (CA), and electrochemical quartz crystal microbalance (E-QCM) analysis. Electrostatic and H-bonding interactions are resolved, with electrostatic interactions responsible for enzyme orientation while enzyme desorption is strongly limited when H-bonding is present at the enzyme-electrode interface. Conversely, enzyme stability is drastically reduced in the absence of H-bonding, and desorptive enzyme loss is confirmed as the main reason for activity decay by E-QCM during CA. This study provides insights into the possible reasons for the reduced activity of immobilized redox enzymes and the role of film loss, particularly H-bonding, in stabilizing bioelectrode performance, promoting avenues for future improvements in bioelectrocatalysis.

Original languageEnglish
Pages (from-to)1886-1897
Number of pages12
JournalACS Catalysis
Volume12
Issue number3
DOIs
Publication statusPublished - 4 Feb 2022

Keywords

  • bioelectrocatalysis
  • enzyme immobilization
  • formate dehydrogenase
  • hydrogenase
  • self-assembled monolayers

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