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An oxygen-insensitive amperometric galactose biosensor based on galactose oxidase co-immobilized with an Os-complex modified redox polymer

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journal contribution
posted on 2023-11-16, 14:33 authored by Carina Figueiredo, Andrea García-Ortega, Tanushree Mandal, Anna Lielpetere, Fadia Cervantes, DENISE DEMURTASDENISE DEMURTAS, EDMOND MAGNEREDMOND MAGNER, Francisco J. Plou, Wolfgang Schuhmann, Donal Leech, Marcos Pita, Antonio L. De Lacey

Monitoring galactose levels in dairy products can help to prevent severe complications with a hereditary metabolic disease such as galactosemia, a life-threatening disease. The current state of the art requires the development of less expensive, more reliable and specific methods to determine galactose levels in food in a practical way. We report the development and optimization of an amperometric biosensor for determination of galactose in dairy products based on galactose oxidase (GaOx) co-immobilized with an osmium-complex modified redox polymer on glassy carbon electrodes. To attain the maximum catalytic currents based on mediated electron transfer, two Os-complex based polymers with different redox potentials and different enzyme:redox polymer ratios were studied. The optimized GaOx-modified electrode gave a maximum electrocatalytic response of galactose oxidation that was not affected by the presence of O2, indicating fast wiring of the enzyme by the Os-complex modified redox polymer. The biosensor that gave the best analytical parameters for galactose detection was further tested for measuring galactose concentration in lactose-containing and lactose-free milk and yogurt samples under aerobic conditions. The results obtained with the amperometric biosensor were validated by high-performance anion-exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD).


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Electrochimica Acta, 2023, 472,143438



Other Funding information

This work has received funding from the European Union's Horizon 2020 research and innovation MSCA ITN program under grant agreement N°813006, IMPLANTSENS. F.J.P acknowledges the grant PID2019–105838RB-C31 from the Spanish Ministry of Science and Innovation.

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