Amperometric glucose sensor based on enhanced catalytic reduction of oxygen using glucose oxidase adsorbed onto core-shell Fe3O4@silica@Au magnetic nanoparticles

Monodisperse Fe3O4 magnetic nanoparticles (NPs) were prepared under facile solvothermal conditions and successively functionalized with silica and Au to form core/shell Fe3O4@silica@Au NPs. Furthermore, the samples were used as matrix to construct a glucose sensor based on glucose oxidase (GOD). The immobilized GOD retained its bioactivity with high protein load of 3.92 x 10(-9) mol.cm(-2), and exhibited a surface-controlled quasi-reversible redox reaction, with a fast heterogeneous electron transfer rate of 7.98 +/- 0.6 s(-1). The glucose biosensor showed a broad linear range up to 3.97 mM with high sensitivity of 62.45 mu A.mM(-1) cm(-2) and fast response (less than 5 s). (c) 2012 Elsevier B.V. All rights reserved.