A Hydrogel Artificial Electronic Tongue for Stable Detection of Glucose

Glucose detection is vital in the food industry for safety and quality management. As a healthy ingredient, the flavor of honey is frequently impacted by the crystallization of glucose. Therefore, determining the glucose level can offer precise reference data for the manufacture of honey. Various approaches have been tried, and the enzyme-based electrochemical analytical method is one of the most important and widely used strategies. However, there are still challenges for most electrochemical methods to achieve stable detection resistant to temperature variation due to the easy inactivation of the enzyme, the poor anti-interference capacity of the detection techniques and other influences from the external environment. Herein, a hydrogel-based electrochemical biosensor is proposed to stably detect glucose even at wide ranges of temperatures via electrochemical impedance spectroscopic (EIS) measurement. The key factor for stable detection relies on the metal-organic framework nanoparticles' protective layer to guarantee the robustness of glucose oxidase (GOx), thereby achieving stable and specific detection for glucose. Moreover, a cascade reaction-induced hydrogel formation in a 3D structure can be used as an impedance readout, which not only amplifies but also further stabilizes the GOx-induced response. The prepared hydrogel-based electrochemical biosensor showed a linear response to the glucose concentration in the range of 0.75-4 mg/mL. Furthermore, the biosensor has excellent anti-interference and temperature stability. High performance liquid chromatography analysis also validated the accuracy of this biosensor in detecting glucose in the honey sample.