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 × 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 μA·mM− 1 cm− 2 and fast response (less than 5 s).