Accepted manuscript
A VOLTAMMETRIC FLAVIN MICROELECTRODE FOR USE IN BIOFILMS
Sensors and actuators. B, Chemical, Vol.161(1), pp.929-937
01/03/2012
Handle:
https://hdl.handle.net/2376/108953
PMCID: PMC3285096
PMID: 22368323
Abstract
Biofilms used in bioelectrochemical systems are expected to transfer electrons using electron transfer mediators. One mediator type, flavins, which includes flavin mononucleotide, riboflavin, and flavin adenine dinucleotide, has been found to be endogenously produced by
Shewanella oneidensis
MR-1. However, the presence and concentration of flavins inside a
S. oneidensis
MR-1 biofilm have never been reported. The goal of this study was to develop a flavin microelectrode capable of measuring flavins inside a living biofilm and apply it to a biofilm which produces flavins. Because flavins are electrochemically active molecules, the flavin microelectrode was based on detection via square-wave voltammetry. The microelectrode consisted of a carbon working electrode with a 10–30 μm tip diameter, a built-in platinum counter electrode, and a Ag/AgCl reference electrode, all enclosed in a glass outer case. The microelectrode was calibrated between 0.1 μM and 10 μM flavins and showed a linear correlation between flavin concentration and peak currents located at −424 mV
Ag/AgCl
on a square-wave voltammogram. We also developed a model to explain the electrochemical mechanism of flavin detection, and to determine the effective surface area of the microelectrode, the standard reduction potential, and the transfer coefficient. We found that the effective surface area of the microelectrode was close to 100 times the projected surface area. The model predicted a standard reduction potential for RF/RFH2 of −419 mV
Ag/AgCl
at 20 °C and a transfer coefficient of 0.45. Lastly, we measured flavin concentration inside a
S. oneidensis
MR-1 biofilm grown on a glass surface using oxygen as the electron acceptor. The flavin concentration reached 0.7 μM, increasing near the bottom of the biofilm, where no oxygen was present. This shows the possibility that flavins are produced in the anaerobic zone to act as intermediate electron acceptors in the deeper parts of the biofilm, where there is no oxygen.
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Details
- Title
- A VOLTAMMETRIC FLAVIN MICROELECTRODE FOR USE IN BIOFILMS
- Creators
- Hung Duc Nguyen - The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, United States of AmericaRyan Renslow - The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, United States of AmericaJerome Babauta - The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, United States of AmericaBulbul Ahmed - The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, United States of AmericaHaluk Beyenal - The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, United States of America
- Publication Details
- Sensors and actuators. B, Chemical, Vol.161(1), pp.929-937
- Academic Unit
- Chemical Engineering and Bioengineering, School of
- Publisher
- Elsevier
- Number of pages
- 9
- Grant note
- T32 GM008336-23 || GM / National Institute of General Medical Sciences : NIGMS
- Identifiers
- 99900547390101842
- Language
- English
- Resource Type
- Accepted manuscript