TY - JOUR A1 - Sarauli, David A1 - Peters, Kristina A1 - Xu, Chenggang A1 - Schulz, Burkhard A1 - Fattakhova-Rohlfing, Dina A1 - Lisdat, Fred T1 - 3D-Electrode architectures for enhanced direct bioelectrocatalysis of pyrroloquinoline quinone-dependent glucose dehydrogenase JF - ACS applied materials & interfaces N2 - We report on the fabrication of a complex electrode architecture for efficient direct bioelectrocatalysis. In the developed procedure, the redox enzyme pyrroloquinoline quinone-dependent glucose dehydrogenase entrapped in a sulfonated polyaniline [poly(2-methoxyaniline-5-sulfonic acid)-co-aniline] was immobilized on macroporous indium tin oxide (macroITO) electrodes. The use of the 3D-conducting scaffold with a large surface area in combination with the conductive polymer enables immobilization of large amounts of enzyme and its efficient communication with the electrode, leading to enhanced direct bioelectrocatalysis. In the presence of glucose, the fabricated bioelectrodes show an exceptionally high direct bioelectrocatalytical response without any additional mediator. The catalytic current is increased more than 200-fold compared to planar ITO electrodes. Together with a high long-term stability (the current response is maintained for >90% of the initial value even after 2 weeks of storage), the transparent 3D macroITO structure with a conductive polymer represents a valuable basis for the construction of highly efficient bioelectronic units, which are useful as indicators for processes liberating glucose and allowing optical and electrochemical transduction. KW - 3D electrode structures KW - macroITO KW - conductive polymer KW - PQQ-GDH KW - direct bioelectrocatalysis KW - bioelectrochemistry Y1 - 2014 U6 - https://doi.org/10.1021/am5046026 SN - 1944-8244 VL - 6 IS - 20 SP - 17887 EP - 17893 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Sarauli, David A1 - Borowski, Anja A1 - Peters, Kristina A1 - Schulz, Burkhard A1 - Fattakhova-Rohlfing, Dina A1 - Leimkühler, Silke A1 - Lisdat, Fred T1 - Investigation of the pH-Dependent Impact of Sulfonated Polyaniline on Bioelectrocatalytic Activity of Xanthine Dehydrogenase JF - ACS catalysis N2 - We report on the pH-dependent bioelectrocatalytic activity of the redox enzyme xanthine dehydrogenase (XDH) in the presence of sulfonated polyaniline PMSA1 (poly(2-methoxyaniline-5-sulfonic acid)-co-aniline). Ultraviolet-visible (UV-vis) spectroscopic measurements with both components in solution reveal electron transfer from the hypoxanthine (HX)-reduced enzyme to the polymer. The enzyme shows bioelectrocatalytic activity on indium tin oxide (ITO) electrodes, when the polymer is present. Depending on solution pH, different processes can be identified. It can be demonstrated that not only product-based communication with the electrode but also efficient polymer-supported bioelectrocatalysis occur. Interestingly, substrate dependent catalytic currents can be obtained in acidic and neutral solutions, although the highest activity of XDH with natural reaction partners is in the alkaline region. Furthermore, operation of the enzyme electrode without addition of the natural cofactor of XDH is feasible. Finally, macroporous ITO electrodes have been used as an immobilization platform for the fabrication of HX-sensitive electrodes. The study shows that the efficient polymer/enzyme interaction can be advantageously combined with the open structure of an electrode material of controlled pore size, resulting in good processability, stability, and defined signal transfer in the presence of a substrate. KW - enzyme bioelectrocatalysis KW - sulfonated polyanilines KW - xanthine dehydrogenase KW - pH-dependent electrochemistry KW - macroporous ITO electrodes Y1 - 2016 U6 - https://doi.org/10.1021/acscatal.6b02011 SN - 2155-5435 VL - 6 SP - 7152 EP - 7159 PB - American Chemical Society CY - Washington ER -