Enhancement of the peroxidase-like activity of cerium-doped ferrite nanoparticles for colorimetric detection of H2O2 and glucoseElectronic supplementary information (ESI) available. See DOI: 10.1039/c7ay00750g

In this report, cerium doped-ferrite nanoparticles (Ce-Fe 3 O 4 NPs), a novel ceria nanostructure, were proposed to have intrinsic peroxidase-like activity toward a classic peroxidase substrate in the presence of H 2 O 2 . The peroxidase-like activity of ceria originated from its facile redox behavior (Ce 3+ /Ce 4+ ) as a catalytic center, thereby explaining the high performance of ferrite-ceria as an artificial enzyme mimicking peroxidase. The as-prepared Ce-Fe 3 O 4 NPs were first demonstrated to possess intrinsic peroxidase-like activity, enhancing the oxidation of the substrate 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of either added H 2 O 2 or H 2 O 2 produced by the enzymatic oxidation of glucose, producing a blue product which could be seen by the naked eye. Based on this, we have successfully established a novel platform for the colorimetric detection of H 2 O 2 with a detection limit of 0.6 μM. Furthermore, the Ce-Fe 3 O 4 NP-based platform can also be used for highly sensitive and selective detection of glucose with a linear range of 5.0-150.0 μM and a detection limit of 1.2 μM. In this report, cerium doped-ferrite nanoparticles (Ce-Fe 3 O 4 NPs), a novel ceria nanostructure, were proposed to have intrinsic peroxidase-like activity toward a classic peroxidase substrate in the presence of H 2 O 2 .