Enzyme mimetic catalyst has recently drawn extensive attention due to its extensive application in biocatalysis, sensing detection and smart material devices. Herein, a synergistic bimetallic enzyme mimetic catalyst, three-dimensional (3D) graphene/Fe3O4-AuNPs, was successfully fabricated which exhibited flexibly switchable peroxidase-like activity. Compared to the traditional 2D graphene-based monometallic composite, the introduced 3D structure and bimetallic anchoring approach dramatically improved the catalytic activity, as well as the catalysis velocity and its affinity for substrate. Fe3O4NPs acted as supporters for AuNPs, which contributed to enhance the efficiency of electron transfer. Based on the measurement of Mott-Schottky plots of graphene and metal anchored hybrids, the catalysis mechanism was elucidated by the decrease of Fermi level resulted from the chemical doping behavior. Notablely, the catalytic activity was able to be regulated by the adsorption and desorption of single-stranded DNA molecules, which laid a basis for its utilization in the construction of single-stranded DNA-based colorimetric biosensors. This strategy not only simplified the operation process including labeling, modification and imprinting, but also protected the intrinsic affinity between the target and biological probe. Accordingly, based on the peroxidase-like activity and its controllability, the enzyme mimetic catalyst successfully adopted in the visualized and label-free detections of glucose, sequence-specific DNA, mismatched nucleotides and oxytetracycline.

Three-dimensional graphene-based bimetallic hybrids with flexibly switchable peroxidase-like catalytic activity

251st National Meeting (2016)

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