Preparation of three-dimensional graphene free-standing electrochemical sensor and its potential application in glucose determination

Lightweight, flexible electrodes based on three-dimensional (3D) graphene have attracted increasing attention owing to their potential applications in many fields. In this work, we developed 3D graphene through different methods and evaluated the potential of these materials as free-standing electrodes. Finally, the 3D graphene synthesized by hydrothermal gelation with cobalt ions as a cross-linking agent had the best electrochemical sensor performance. With our focus on practical applications, we further modified polydopamine and concanavalin A onto the 3D graphene to make it suitable for the detection of glucose. Under the optimum conditions, the impedance change in the free-standing electrode and the concentration of glucose have a good linear relationship in the range of 0.05-0.35 mu mol/L and a limit of detection of 0.01 mu mol/L. The electrochemical biosensor exhibited good sensitivity, selectivity, reproducibility, and stability. The fabricated biosensor was employed for the detection of glucose in mouse serum samples and provided satisfactory results. Therefore, the synthesized 3D graphene offers a new opportunity for immobilizing other biomolecules and fabricating biosensors. [GRAPHICS] .