Electrochemical Sensor Based on Magnetic Electrode Modified with Magnetic Molecularly Imprinted Nanoparticles Immobilized Hemoglobin for Determination of Hydrogen Peroxide

In this work, the surface-imprinted technique was used to prepare magnetic hemoglobin (Hb) imprinted nanoparticles, using FeO@SiO NPs as the carrier, Hb as the template molecule, and tetraethyl orthosilicate (TEOS) as the imprinted polymer monomer. The nanoparticles had a core-shell structure, with magnetic FeO NPs as the core and Hb imprinted polymers as the shell. Therefore, Hb could be concentrated and fixed on the surface of the magnetic imprinted nanoparticles (MMIPs NPs). Furthermore, MMIPs NPs were immobilized with chitosan (CS) on the surface of a magnetic electrode to constitute Hb enzyme-like biosensor to catalyze the reduction of hydrogen peroxide (HO). Compared with magnetic non-imprinted polymer nanoparticles (MNIPs NPs), the MMIPs NPs biosensor enhanced the response by 14.3%. Notably, an introduction of a magnetic field made the biosensor more sensitive owing to the paramagnetism of MNIPs NPs, Hb and O molecules. The reduction current of HO on Hb/MMIPs NPs modified magnetic glassy carbon electrode increased by 60.0%. Under the optimum condition, the linear detection range of HO was 25 ~ 200 μmol·L with the detection limit of 3 μmol·L (S/N = 3), which showed that Hb enzyme-like biosensor had a good catalytic performance for HO