Glucose Oxidase Immobilized on a Functional Polymer Modified Glassy Carbon Electrode and Its Molecule Recognition of Glucose

In the present study, a glucose oxidase (GluOx) direct electron transfer was realized on an aminated polyethylene glycol (mPEG), carboxylic acid functionalized multi-walled carbon nanotubes (fMWCNTs), and ionic liquid (IL) composite functional polymer modified glassy carbon electrode (GCE). The amino groups in PEG, carboxyl groups in multi-walled carbon nanotubes, and IL may have a better synergistic effect, thus more effectively adjust the hydrophobicity, stability, conductivity, and biocompatibility of the composite functional polymer film. The composite polymer membranes were characterized by cyclic voltammetry (CV), ultraviolet-visible (UV-Vis) spectrophotometer, fluorescence spectroscopy, electrochemical impedance spectroscopy (EIS), and transmission electron microscopy (TEM), respectively. In 50 mM, pH 7.0 phosphate buffer solution, the formal potential and heterogeneous electron transfer constant (k_s) of GluOx on the composite functional polymer modified GCE were −0.27 V and 6.5 s⁻¹, respectively. The modified electrode could recognize and detect glucose linearly in the range of 20 to 950 μM with a detection limit of 0.2 μM. The apparent Michaelis-Menten constant (K_m^app) of the modified electrode was 143 μM. The IL/mPEG-fMWCNTs functional polymer could preserve the conformational structure and catalytic activity of GluOx and lead to high sensitivity, stability, and selectivity of the biosensors for glucose recognition and detection.