Impedimetric aptasensor for kanamycin by using carbon nanotubes modified with MoSe₂ nanoflowers and gold...

An aptamer based impedimetric method is described for the determination of kanamycin. A hydrothermal route was applied to synthesize molybdenum selenide nanoflowers (MoSe₂) which are promising materials for use in sensing interfaces due to their high specific surface and excellent electrical conductivity. Carbon nanotubes were then decorated with the MoSe₂ nanoflowers and gold nanoparticles (AuNP/CNT/MoSe₂) and placed on a glassy carbon electrode to serve as a signal amplifier. An amino-terminal kanamycin-specific aptamer was covalently linked to carboxy groups of acid-oxidized CNTs on the electrode to act as the signalling probe. The various steps during the construction of the modified electrode were monitored by scanning electron microscopy, wavelength-dispersive and energy-dispersive X-ray spectroscopy, electrochemical impedance spectroscopy, and cyclic voltammetry. The change in electrochemical signal was quantified by electrochemical impedance spectroscopy, typically at a working voltage of 0.22 V vs. Ag/AgCl. The calibration plot is linear in the 1 pM-0.1 nM and 100 nM-10 μM kanamycin concentration range and has a 0.28 pM detection limit. The assay is outstandingly selective, sensitive, stable and reproducible. Graphical abstract ᅟ.