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

Carina Figueiredo, Andrea García-Ortega, Tanushree Mandal, Anna Lielpetere, Fadia Cervantes, Denise Demurtas, Edmond Magner, Francisco J. Plou, Wolfgang Schuhmann, Donal Leech, Marcos Pita, Antonio L. De Lacey

Research output: Contribution to journalArticlepeer-review

Abstract

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).

Original languageEnglish
Article number143438
JournalElectrochimica Acta
Volume472
DOIs
Publication statusPublished - 20 Dec 2023

Keywords

  • Biosensor
  • Dairy products
  • Galactose
  • Galactose oxidase
  • Redox polymers

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