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

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. (C) 2012 Elsevier B.V. All rights reserved.