Light as Trigger for Biocatalysis: Photonic Wiring of Flavin Adenine Dinucleotide-Dependent Glucose Dehydrogenase to Quantum Dot-Sensitized Inverse Opal TiO2 Architectures via Redox Polymers

Riedel, M. and Parak, W.J. and Ruff, A. and Schuhmann, W. and Lisdat, F.

Volume: 8 Pages: 5212-5220
DOI: 10.1021/acscatal.8b00951
Published: 2018

The functional coupling of photoactive nanostructures with enzymes creates a strategy for the design of light-triggered biocatalysts. This study highlights the efficient wiring of flavin adenine dinucleotide (FAD)-dependent glucose dehydrogenase (FAD-GDH) to PbS quantum dot (QD)-sensitized inverse opal TiO2 electrodes (IO-TiO2) by means of an Os-complex-containing redox polymer for the light-driven glucose oxidation. For the construction of IO-TiO2 scaffolds, a template approach has been developed, enabling the tunability of the surface area and a high loading capacity for the integration of QDs, redox polymer, and enzyme. The biohybrid signal chain can be switched on with light, generating charge carriers within the QDs, triggering a multistep electron-transfer cascade from the enzyme toward the redox polymer via the QDs and finally to the IO-TiO2 electrode. The resulting anodic photocurrent can be modulated by the potential, the excitation intensity, and the glucose concentration, providing a new degree of freedom for the control of biocatalyic reactions at electrode interfaces. Maximum photocurrents of 207 μA cm-2 have been achieved in the presence of glucose, and a first gain of electrons from the biocatalytic reaction is found at -540 mV vs Ag/AgCl, 1 M KCl, which lowers the working potential by >500 mV as compared to light-insensitive electrodes. The biohybrid system combines the advantages of a high surface area of IO films, an efficient charge-carrier generation and separation at the QDs/TiO2 interface, and an efficient wiring of FAD-GDH to the QDs via a redox polymer, resulting in photo(bio)anodes of high performance for sensing and power supply. © 2018 American Chemical Society.

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