A novel CuFe₂O₄ nanospheres molecularly imprinted polymers modified electrochemical sensor for lysozyme determination

A selective and sensitive electrochemical sensor was proposed on the basis of a nanostructured magnetic molecularly imprinted polymer (CuFe₂O₄-MIP) modified glassy carbon electrode (GCE) for the electrochemical detection of lysozyme. CuFe₂O₄ nanospheres with porous structure have been prepared via a hydrothermal method. Surface imprinting was employed to prepare molecularly imprinted polymer nanoparticles on the CuFe₂O₄ nanosphere surface. The synthesized magnetic nanoparticles (CuFe₂O₄-MNPs) and CuFe₂O₄-MIP were characterized with High-Resolution Transmission Electron Microscopy (HRTEM), X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR) and Vibrating Sample Magnetometer (VSM) to verify successful preparation. Then cyclic voltammetry, electrochemical impedance spectroscopy and differential pulse voltammetry were employed to test the electrochemical property of the sensor, and this sensor demonstrated high electrochemical response. The results prove that the as-synthesized CuFe₂O₄ nanospheres have high specific capacitance characteristics and good conductivity. Under optimal conditions, the constructed multifunctional sensor presented good linearity from 0.05 to 0.8 μg mL⁻¹with the detection limit of 1.58 × 10⁻³ μg mL⁻¹for target lysozyme. Further competitive rebinding experiments results showed that this sensing material is highly selective and sensitive for lysozyme determination, and had been successfully applied to detect target protein in complex biological samples. The presented method can be applied to the detection of trace protein in biological samples.