Monofunctional pyrenes at carbon nanotube electrodes for direct electron transfer H2O2 reduction with HRP and HRP-bacterial nanocellulose.

Sara Bocanegra-Rodríguez, Carmen Molins-Legua, Pilar Campíns-Falcó, Fabien Giroud, Andrew J Gross, Serge Cosnier

Biosensors & bioelectronics 2021 Sep 01

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The non-covalent modification of carbon nanotube electrodes with pyrene derivatives is a versatile approach to enhance the electrical wiring of enzymes for biosensors and biofuel cells. We report here a comparative study of five pyrene derivatives adsorbed at multi-walled carbon nanotube electrodes to shed light on their ability to promote direct electron transfer with horseradish peroxidase (HRP) for H2O2 reduction. In all cases, pyrene-modified electrodes enhanced catalytic reduction compared to the unmodified electrodes. The pyrene N-hydroxysuccinimide (NHS) ester derivative provided access to the highest catalytic current of 1.4 mA cm-2 at 6 mmol L-1 H2O2, high onset potential of 0.61 V vs. Ag/AgCl, insensitivity to parasitic H2O2 oxidation, and a large linear dynamic range that benefits from insensitivity to HRP "suicide inactivation" at 4-6 mmol L-1 H2O2. Pyrene-aliphatic carboxylic acid groups offer better sensor sensitivity and higher catalytic currents at ≤ 1 mmol L-1 H2O2 concentrations. The butyric acid and NHS ester derivatives gave high analytical sensitivities of 5.63 A M-1 cm-2 and 2.96 A M-1 cm-2, respectively, over a wide range (0.25-4 mmol-1) compared to existing carbon-based HRP biosensor electrodes. A bacterial nanocellulose pyrene-NHS HRP bioelectrode was subsequently elaborated via "one-pot" and "layer-by-layer" strategies. The optimised bioelectrode exhibited slightly weaker voltage output, further enhanced catalytic currents, and a major enhancement in 1-week stability with 67% activity remaining compared to 39% at the equivalent electrode without nanocellulose, thus offering excellent prospects for biosensing and biofuel cell applications. Copyright © 2021 Elsevier B.V. All rights reserved.

Citation

Sara Bocanegra-Rodríguez, Carmen Molins-Legua, Pilar Campíns-Falcó, Fabien Giroud, Andrew J Gross, Serge Cosnier. Monofunctional pyrenes at carbon nanotube electrodes for direct electron transfer H2O2 reduction with HRP and HRP-bacterial nanocellulose. Biosensors & bioelectronics. 2021 Sep 01;187:113304