Electrical Cable‐based Copper Disk Electrodes as Oxidase Biosensor Platforms with Cathodic H2O2 Readout

Abstract

AbstractWe report the first utilization of copper disk electrodes as suitable cathodic transducer platforms for glucose biosensors. Simple and cheap Cu disk electrodes were fabricated from ordinary electrical cable by cementing into a glass tube with epoxy resin and subsequent polishing to expose the active area. Glucose oxidase was immobilized on the electrode tips by entrapment in dropped and dried polymeric Nafion deposits. At a H2O2 detection potential of −0.15 V vs. a reference electrode, the linear response range of fabricated cable Cu glucose biosensors was 20–1500 µM, with a sensitivity of about 700 nA µM−1 cm−2. Quantitative analysis of glucose‐supplemented buffer solutions showed a recovery of 106±4 % (n=3). The principal advantage of the glucose biosensors described in this study, compared to other options, is the simplicity of the cathodic H2O2 readout, which exploits cheap and readily available electrical cable, without any extra surface modification with catalytically active micro‐ or nanomaterials. The analytical performance of the biosensor is competitive and suggests potential applications in routine glucose testing, in particular in academic teaching and research laboratories. The work is also a starting point for transfer of the methodology from simple cable Cu electrodes to arrays of miniaturized Cu sensors, using a combination of microlithography, electroforming and molding (LIGA).