Enhancement of the peroxidase-like activity of cerium-doped ferrite nanoparticles for colorimetric detection of H2O2 and glucose

Abstract

In this report, cerium doped-ferrite nanoparticles (Ce–Fe₃O₄ NPs), a novel ceria nanostructure, were proposed to have intrinsic peroxidase-like activity toward a classic peroxidase substrate in the presence of H₂O₂. The peroxidase-like activity of ceria originated from its facile redox behavior (Ce³⁺/Ce⁴⁺) as a catalytic center, thereby explaining the high performance of ferrite–ceria as an artificial enzyme mimicking peroxidase. The as-prepared Ce–Fe₃O₄ 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 H₂O₂ or H₂O₂ 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 H₂O₂ with a detection limit of 0.6 μM. Furthermore, the Ce–Fe₃O₄ 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.