A molecularly imprinted polymer combined with dual functional Au@Fe3O4 nanocomposites for sensitive detection of kanamycin

Based on molecular imprinting and nanotechnology, a highly specific and sensitive electrochemical aptasensor was proposed for assaying kanamycin (KAN). First, chitosan-graphene (CG) composite multilayer films and Au nanoparticles (AuNPs) were applied to modify a glassy carbon electrode (GCE) for augmented "electron antennae". Then, we constructed a KAN sensor using functional monomer of 3-aminophenylboronic acid (3-APBA) as trap. Au@Fe3O4 nanocomposites, Fe3O4 nanoparticles (Fe(3)O(4)NPs) loaded with AuNPs, were dual functionally modified with beta-cyclodextrin-ferrocene (Fc/beta-CD-SH) and KAN aptamers (APT/Fc/beta-CD-SH/Au@Fe3O4) were applied as the tracing tag. The KAN aptamer acted as the bind unit to specifically identify the KAN captured by the imprinted cavities on the MIP modified electrode surface, while the Fc/beta-CD-SH was used as a signal unit for KAN quantification. The presented assay exhibited a good linear relationship between KAN concentration (10-500 nM) and the strength of the electrochemical signal, with a detection limit of 1.87 nM and a correlation coefficient of 0.98. The selectivity, stability and reproducibility of the proposed sensor were acceptable. Furthermore, it was used successfully to detect KAN in different aqueous solution, such as in spiked milk, the proposed sensor could be applied for specifically, sensitively and rapid determination for antibiotic contamination in food, water and biological samples. (C) 2020 Elsevier B.V. All rights reserved.