A simple hydrothermal synthesis and fabrication of zinc oxide-copper oxide heterostructure for the sensitive determination of nonenzymatic glucose biosensor

Zinc oxide nanorods and copper oxide nanospheres (ZnO-CuO), were prepared through a simple hydrothermal method. The nanorods and nanospheres readily occurred in the presence of polyethyleneimine which acts as a stabilizing or reducing agent for the growth of nanocomposite and makes them more stable. The obtained nanocomposite was confirmed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction and cyclic voltammetric studies. The nanocomposite ZnO-CuO is further coated on the glassy carbon electrode (ZnO-CuO/GCE). The ZnO-CuO/GCE showed an excellent electrocatalytic performance toward the determination of glucose. The as-modified electrode achieved wider linear range from 0.1 to 4167 μM with a very low detection limit (LOD) of 0.038 μM. The developed sensor displayed high sensitivity of 1457.5 μA mM^-1 cm^-2. In addition, the ZnO-CuO/GCE is able to detect the glucose even in the presence of biologically interfering molecules. The sensor achieved appreciable repeatability, reproducibility and long term stability (up to 38 days). The practicality of the sensor was demonstrated in the human serum samples.