Abstract
A polyelectrolyte film-coated electrode for the quantitative detection of glucose was reported. Carbon nanotubes, graphene oxide and polyelectrolyte with a ferrocenyl group were used to modify an enzyme electrode to facilitate the electron transfer between glucose oxidase and the electrode. Cyclic voltammetry and amperometric methods were adopted to investigate the effects of different polyelectrolytes and carbon nanomaterials on the electrochemical properties of enzyme electrodes. The results indicate that the ferrocenyl groups on a polyelectrolyte skeleton act as a mediator between the redox center of glucose oxidase and the electrode, which efficiently enhances the electron transfer between a glassy carbon electrode and glucose oxidase. The calibration curve of the sensor shows a linear range from 0.2 to 5 mM for glucose response. The sensor can achieve 95% of the steady-state current within 10 s. The electrodes also present high operational stability and long-term storage stability.
Highlights
Among the diverse glucose sensors reported, the glucose oxidase (GOx)-based glucose biosensor is a widely used commercial sensor that has undergone tremendous development due to its excellent performance [18,19]; there are still some problems to be improved such as the sensitivity, responsiveness and stability in its electrical signal
Substances chosen as electron transfer mediators should meet the following requirements: Good electrochemical reversibility, low redox potentials, good stability, low solubility in water and good resistance to oxygen
Benzotriazol-1yl-oxytripyrrolidinophosphonium hexafluorophosphate (PyBOP), ferrocene-carboxylic acid D(+)glucose and dialytic tubes were obtained from and sodium hypochlorite aqueous solution were purchased from Aladdin Inc. (Shanghai, China)
Summary
A simple, accurate and quick determination method of trace glucose is significantly important.As such, various glucose sensors have been developed in recent years and applied in many fields, including clinical chemistry [1,2,3,4,5], the food and beverage industry [6,7,8,9], environmental monitoring [10,11,12,13] and the military [14,15,16,17]. The GOx biosensor conventionally uses oxygen as the electron transfer mediator and indirectly measures glucose by evaluating the oxygen consumption or the amount of the H2 O2 formation in the substrate catalysis process with GOx [20]. Such an approach is affected by the disturbance from electroactive substances such as ascorbic acid [21] and the fluctuation of the oxygen concentration in the environment [22]. Substances chosen as electron transfer mediators should meet the following requirements: Good electrochemical reversibility (corresponding to a fast electron-transfer rate), low redox potentials (corresponding to little disturbance from electroactive substances), good stability, low solubility in water and good resistance to oxygen
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