A novel glucose biosensor based on the immobilization of glucose oxidase on layer-by-layer assembly film of copper phthalocyanine functionalized graphene

•A novel electrochemical glucose biosensor based on the graphene multilayer film has been developed.•Graphene was noncovalently functionalized with two kinds of copper phthalocyanines.•The multilayer film was prepared through layer-by-layer assembly technique.•The biosensor exhibited good analytical performance for glucose detection. A negatively charged glassy carbon electrode (GCE) was formed through the electrochemical modification of sulfanilic acid (ABS). Subsequently, graphene composites functionalized with copper phthalocyanine-3,4′,4″,4‴-tetrasulfonic acid tetrasodium salt (TSCuPc) or alcian blue pyridine variant (AB) were assembled layer-by-layer (LbL) via alternate electrostatic adsorption onto the ABS/GCE surface to obtain a uniform and stable graphene multilayer film modified electrode. With glucose oxidase (GOD) as an enzyme model, a novel GOD/Nafion/(LbL)3.5/ABS/GCE electrochemical biosensor has been developed. SEM and Raman spectra were utilized to characterize the functionalized graphene nanocomposites and modified electrodes. The electrochemical performance of the biosensor was investigated by cyclic voltammetry. The results demonstrated that the graphene multilayer film significantly enhanced the electrocatalytic activity of the modified electrode toward O2 reduction. Based on the O2 consumption during the oxidation process of glucose, the as-prepared biosensor exhibited a low detection limit of 0.05mmolL−1, excellent reproducibility, stability, sensitivity and selectivity, and its response was linear up to 8mmolL−1 glucose concentration. Accordingly, the multilayer film consisting of copper phthalocyanine functionalized graphene nanocomposites offers a novel and effective platform for the electrochemical biosensing applications.