Tailoring 1,4-naphthoquinone with electron-withdrawing group: toward developing redox polymer and FAD-GDH based hydrogel bioanode for efficient electrocatalytic glucose oxidation

Abstract

Redox polymer hydrogels have been proved to be very promising for biofuel cells design and electrochemical biosensing. Here we report that a facile hydrogel bioanode based on electron-withdrawing nitro-group tailored 1,4-naphthoquinone (1,4-NQ)-appended redox polymer and flavin adenine dinucleotide-dependent glucose dehydrogenase (FAD-GDH) can dramatically improve the catalytic performance of glucose oxidation, for which a high current density of 1.97±0.06mAcm−2 and low onset potential of −0.13V (vs. Ag/AgCl) can be achieved in 50mM glucose solution without using any nanomaterials as electrode supports. Further, both electron-donating groups modified 1,4-NQs and electron-withdrawing nitro-group 1,4-NQs were synthesized to investigate their electrochemical properties. It was found that the enhanced catalytic performance can be mainly contributing from the nitro group-modified 1,4-NQs appended redox polymer, which shifted the formal potential in the positive direction and provided sufficient electrochemical driving force for glucose oxidation. Finally, this hydrogel bioanode was combined with a bilirubin oxidase based biocathode to construct a single-compartment glucose/O2 biofuel cell with a high power output of 0.28±0.03mWcm−2 and open circuit potential of 0.69V. Moreover, the O2-insensitive FAD-GDH could improve the cell stability obviously compared with glucose oxidase based cell. This study provides an alternative route to develop glucose biosensor or biofuel cell for directly harvesting energy from glucose.