Immobilization of redox enzymes on nanoporous gold electrodes: applications in biofuel cells
Conghaile, Peter Ó
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Siepenkoetter, Till; Salaj-Kosla, Urszula; Xiao, Xinxin; Conghaile, Peter Ó; Pita, Marcos; Ludwig, Roland; Magner, Edmond (2016). Immobilization of redox enzymes on nanoporous gold electrodes: applications in biofuel cells. ChemPlusChem 82 (4), 553-560
Nanoporous gold (NPG) electrodes were prepared by dealloying sputtered gold: silver alloys. Electrodes of different thicknesses and pore sizes areas were prepared by varying the temperature and duration of the dealloying procedure; these were then used as supports for FAD-dependent glucose dehydrogenase (GDH) (Glomorella cingulata) and bilirubin oxidase (BOx) (Myrothecium verrucaria). Glucose dehydrogenase was immobilized by drop-casting a solution of the enzyme with an osmium redox polymer together with a crosslinked polymer, whereas bilirubin oxidase was attached covalently through carbodiimide coupling to a diazonium-modified NPG electrode. The stability of the bilirubin-oxidase-modified NPG electrode was significantly improved in comparison with that of a planar gold electrode. Enzyme fuel cells were also prepared; the optimal response was obtained with a BOx-modified NPG cathode (500 nm thickness) and a GDH-modified anode (300 nm), which generated power densities of 17.5 and 7.0 mu W cm(-2) in phosphate-buffered saline and artificial serum, respectively.