Voltammetric nonenzymatic sensing of glucose by using a porous nanohybrid composed of CuS@SiO2 spheres and polypyrrole.

Porous spheres of CuS@SiO2 were obtained by deposition of CuS on silica spheres through a one-step chemical method. Subsequently, polypyrrole (PPy) was deposited on the CuS@SiO2 spheres. The formation of the porous spheres was elucidated by control experiments and physical characterizations. The nanohybrid was placed on a glassy carbon electrode (GCE) surface where it displays good electrocatalytic activity in terms of glucose electrooxidation with an optimum at a working potential of 0.55 V (vs. Ag/AgCl) in 0.1 M NaOH solution. The PPy-CuS@SiO2 achieves an extremely high sensitivity (505.3 µA mM-1 cm-2), wide linear range (10 µM-4.2 mM), low detection limit (1.0 µM), short response time (˂ 0.5 s), high selectivity, long-term durability, and reproducibility. The fabricated electrode based on PPy-CuS@SiO2 was further used for the determination of glucose in blood sample with good recoveries. Graphical abstract Schematic representation of the method for fabrication of polypyrrole-coated porous CuS@SiO2 sphere.