The immobilization of glucose oxidase at manganese dioxide particles-decorated reduced graphene oxide sheets for the fabrication of a glucose biosensor

Here, we describe a simple approach for the efficient immobilization of poly-l-lysine (PLL) impregnated glucose oxidase (GOx) at a manganese dioxide (MnO2)-decorated chemically reduced graphene oxide (CRGO) composite film modified electrode. The MnO2/CRGO film was analyzed by various techniques such as scanning electron microscopy, UV-visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and electrochemical impedance spectroscopy. MnO2 particles are uniformly deposited at the CRGO surface through an easily adoptable electropolymerization method. The as-prepared (GOx-PLL/MnO2/CRGO) composite film exhibited a surface coverage concentration (Λ) of 2.68 × 10-10 mol/cm-2, indicative of high GOx loading. The heterogeneous rate constant for the redox reaction of GOx has been calculated to be 4.92 s-1. A glucose biosensor was fabricated which exhibits a wide linear range from 0.04 to 10 mM with a limit of detection of 0.02 mM (S/N = 3). The proposed inexpensive, simple, and sensitive sensing approach based on the MnO2/CRGO nanocomposite electrode can be a promising method for the determination of glucose present in the clinical and environmental food analysis.