ORIGINAL PAPER Impedimetric aptasensor for kanamycin by using carbon nanotubes modified with MoSe 2 nanoflowers and gold nanoparticles as signal amplifiers Azadeh Azadbakht 1 & Amir Reza Abbasi 2 Received: 22 August 2018 /Accepted: 29 November 2018 # Springer-Verlag GmbH Austria, part of Springer Nature 2018 Abstract An aptamer based impedimetric method is described for the determination of kanamycin. A hydrothermal route was applied to synthesize molybdenum selenide nanoflowers (MoSe 2 ) 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 MoSe 2 nanoflowers and gold nanoparticles (AuNP/CNT/MoSe 2 ) 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. Keywords Amino-terminated ssDNA . Molybdenum selenide nanoflowers . Kanamycin . Carbon nanotube Introduction Kanamycin as aminoglycoside antibiotics disturb the bacteria functions by interrupting the different steps of proteins syn- thesis [1]. However, kanamycin demonstrate excellent anti- bacterial effects, abuse of it induce many negative conse- quences including anaphylactic reactions to the drug, hearing problems, tinnitus, respiratory failure, and ototoxicity and nephrotoxicity [2–5]. Moreover, the remnant of kanamycin in the foodstuff such as honey and milk and animal derived foods can be considered as a serious threat to human beings. Therefore, European Union has set maximum kanamycin res- idue limits of 150 μg.kg -1 for milk, 600 μg.kg -1 for liver, and 100 μg. Kg -1 for meat [6]. By now, varieties analytical approaches have been devel- oped to control and trace the kanamycin levels in foodstuff including colloidal gold test strips [7], microbiological multi- residue system [8], surface plasmon resonance (SPR) [9], fluorescence [10], colorimetry [11], electrochemical methods [12], and enzyme linked immunosorbent assay (ELISA) [13]. Despite simple designs of enzymatic-based analyses and their capability of rapid analysis, they often fail to produce a strong electrical signal and need intermediates for electrons transfer. Also, the application of enzyme may be restricted due to the failure in the precise control of enzyme activity, low stability and specificity. Along with above mentioned methods, more selective methods such as liquid chromatography as a conven- tional method has been used for detection of kanamycin with high sensitivity [14]. The large amounts of volatile organic solvents used in the mobile phase make this technique as an undesirable method to most analysts. Consequently, it is de- sirable to introduce effective systems with high sensitivity and Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00604-018-3130-x) contains supplementary material, which is available to authorized users. * Azadeh Azadbakht Azadbakht.a@gmail.com 1 Department of Chemistry, Khorramabad Branch, Islamic Azad University, Khorramabad, Iran 2 Faculty of Chemistry, Razi University, Kermanshah 67149, Iran Microchimica Acta https://doi.org/10.1007/s00604-018-3130-x