Facile preparation of novel core-shell enzyme-Au-polydopamine-Fe₃O₄ magnetic bionanoparticles for glucosesensor

In this study, a novel biomolecule immobilization approach has been proposed to the synthesis of multi-functional core-shell glucose oxidase-Au-polydopamine-Fe₃O₄ magnetic bionanoparticles (GOx-Au-PDA-Fe₃O₄ MBNPs) using the one-pot chemical polymerization method. Then, a high performance biosensor has been constructed by effectively attaching the proposed GOx-Au-PDA-Fe₃O₄ MBNPs to the surface of the magnetic glassy carbon electrode. Scanning electron microscope, energy dispersive x-ray spectrometer, UV-vis spectroscopy, and electrochemical methods were used to characterize the GOx-Au-PDA-Fe₃O₄ MBNPs. The resultant GOx-Au-PDA-Fe₃O₄ MBNPs not only have the magnetism of Fe₃O₄ nanoparticles which makes them easily manipulated by an external magnetic field, but also have the excellent biocompatibility of PDA to maintain the native structure of the GOx, and good conductivity of Au nanoparticles which can facilitate the direct electrochemistry of GOx in the biofilm. Hence, the present GOx-Au-PDA-Fe₃O₄ biofilm displays good linear amperometric response to glucose concentration ranging from 0.02 to 1.875 mM. This efficient biomolecule immobilization platform is recommended for the preparation of many other MBNPs with interesting properties and application potentials in many fields, such as biosensing, biocatalysis, biofuel cells, and bioaffinity separation.