Laccase Biosensor Based on Phytic Acid Modification of Nanostructured SiO2 Surface for Sensitive Detection of Dopamine

In this work, three kinds of nanostructured silica–phytic acid (SiO2–PA) materials with diverse morphologies including spherical SiO2–PA (s-SiO2–PA), rod-like (r-SiO2–PA), and helical SiO2–PA (h-SiO2–PA) were prepared with the help of electrostatic interaction. The SiO2–PA nanomaterials with different morphologies were characterized by using transmission electron microscopy (TEM), Fourier transform infrared (FTIR), electrochemical impedance spectroscopy (EIS), and circular dichroism spectrum (CD). Diverse morphologies of SiO2–PA were used as electrode decorated materials to achieve a high efficiency for electrochemical dopamine (DA) detection. The laccase biosensors were fabricated by immobilizing different morphologies of SiO2–PA nanomaterials and laccase onto the glassy carbon electrode (GCE) surface, successively. Then the electrochemical responses of the different morphologies of nanostructured SiO2–PA nanomaterials to laccase were discussed. Results indicated that compared to laccase/s-SiO2–PA and laccase/r-SiO2–PA, the laccase/h-SiO2–PA-modified electrode showed the best electrochemical performances.