Electrochemical Sensing of Glucose Using Glucose Oxidase/PEDOT:4-Sulfocalix [4]arene/MXene Composite Modified Electrode.

Glucose is one of the most important monosaccharides found in the food, as a part of more complex structures, which is a primary energy source for the brain and body. Thus, the monitoring of glucose concentration is more important in food and biological samples in order to maintain a healthy lifestyle. Herein, an electrochemical glucose biosensor was fabricated by immobilization of glucose oxidase (GOX) onto poly(3,4-ethylenedioxythiophene):4-sulfocalix [4]arene (PEDOT:SCX)/MXene modified electrode. For this purpose, firstly, PEDOT was synthesized in the presence of SCX (counterion) by the chemical oxidative method. Secondly, MXene (a 2D layered material) was synthesized by using a high-temperature furnace under a nitrogen atmosphere. After that, PEDOT:SCX/MXene (1:1) dispersion was prepared by ultrasonication which was later utilized to prepare PEDOT:SCX/MXene hybrid film. A successful formation of PEDOT:SCX/MXene film was confirmed by HR-SEM, Fourier transform infrared (FT-IR), and Raman spectroscopies. Due to the biocompatibility nature, successful immobilization of GOX was carried out onto chitosan modified PEDOT:SCX/MXene/GCE. Moreover, the electrochemical properties of PEDOT:SCX/MXene/GOX/GCE was studied through cyclic voltammetry and amperometry methods. Interestingly, a stable redox peak of FAD-GOX was observed at a formal potential of -0.435 V on PEDOT:SCX/MXene/GOX/GCE which indicated a direct electron transfer between the enzyme and the electrode surface. PEDOT:SCX/MXene/GOX/GCE also exhibited a linear response against glucose concentrations in the linear range from 0.5 to 8 mM. The effect of pH, sensors reproducibility, and repeatability of the PEDOT:SCX/MXene/GOX/GCE sensor were studied. Finally, this new biosensor was successfully applied to detect glucose in commercial fruit juice sample with satisfactory recovery.