Abstract
AbstractIn this study, a new lactose biosensor has been developed in which the 3,4-ethylenedioxythiophene/thiophene (EDOT/Th) copolymer is used as a transducer. The EDOT/Th copolymer was deposited on the glassy carbon electrode to be used as the working electrode. In addition to the working electrode, the three-electrode system was used in both the electrochemical synthesis and in the biosensor measurements. Lactase (β-galactosidase) that catalyzes the breakdown of lactose into monosaccharides (glucose and galactose) and galactose oxidase that catalyzes the oxidation of the resulting galactose were attached to the copolymer by a cross-linker on the modified working electrode. The response of the enzyme electrode to lactose was determined by cyclic voltammetry (CV) at +0.12 V. Enzyme electrode optimization parameters (pH, temperature, enzyme concentration, etc.) were performed. Fourier transform infrared spectroscopy, scanning electron microscopy and CV methods were used to support copolymer formation. In addition, the characteristics of the enzyme electrode prepared in this study (Km, 0.02 mM; activation energy Ea, 38 kJ/mol; linear working range, up to 1.72 mM; limit of detection, 1.9 × 10−5 M and effects of interferents [uric acid and ascorbic acid]) were determined.
Highlights
In recent years, electrochemical sensors have an increasing attention due to their excellent properties, especially in electroanalytical determination of important analytes
This study indicates the usability of EDOT/Th copolymer-modified galactose oxidase/β-galactosidase entrapped enzyme electrodes for the determination of lactose
Copolymerization of monomers was achieved on the glassy carbon (GC) electrode by Cyclic voltammetry (CV) in the range of −0.10 to 1.50 V at room temperature
Summary
Electrochemical sensors have an increasing attention due to their excellent properties, especially in electroanalytical determination of important analytes. Among them conductive polymers, which were first discovered in 1977 by Shirakawa and co-workers, have found special attention due to their excellent characteristics such as low cost, environmental stability, ease of synthesis, high surface area, long-term stability and high electron affinity [2,3,4]. Polythiophenes have a lot of application areas such as transistors [10], electrochromic devices [11], light-emitting devices [12], batteries [13], adsorption materials [14], sensors and biosensors [15,16].
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