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A Self‐Powered Ethanol Biosensor
Author(s) -
Ruff Adrian,
Pinyou Piyanut,
Nolten Melinda,
Conzuelo Felipe,
Schuhmann Wolfgang
Publication year - 2017
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.201600864
Subject(s) - horseradish peroxidase , chemistry , prussian blue , redox , biosensor , polymer , electron transfer , alcohol dehydrogenase , cyclic voltammetry , glassy carbon , chemical engineering , combinatorial chemistry , nuclear chemistry , electrochemistry , ethanol , electrode , inorganic chemistry , organic chemistry , biochemistry , engineering , enzyme
We describe the fabrication of a self‐powered ethanol biosensor comprising a β‐NAD + ‐dependent alcohol dehydrogenase (ADH) bioanode and a bienzymatic alcohol oxidase (AOx) and horseradish peroxidase (HRP) biocathode. β‐NAD + is regenerated by means of a specifically designed phenothiazine dye (i. e. toluidine blue, TB) modified redox polymer in which TB was covalently anchored to a hexanoic acid tethered poly(4‐vinylpyridine) backbone. The redox polymer acts as an immobilization matrix for ADH. Using a carefully chosen anchoring strategy through the formation of amide bonds, the potential of the TB‐based mediator is shifted to more positive potentials, thus preventing undesired O 2 reduction. To counterbalance the rather high potential of the TB‐modified polymer, and thus the bioanode, a high‐potential AOx/HRP‐based biocathode is suggested. HRP is immobilized in a direct‐electron‐transfer regime on screen‐printed graphite electrodes functionalized with multi‐walled carbon nanotubes. The nanostructured cathode ensures the wiring of the iron‐oxo complex within oxidized HRP, and thus a high potential for the reduction of H 2 O 2 of about +550 mV versus Ag/AgCl/3 M KCl. The proposed biofuel cell exhibits an open‐circuit voltage (OCV) of approximately 660 mV and was used as self‐powered device for the determination of the ethanol content in liquor.