A novel electrochemical aptasensor for sensitive detection of kanamycin based on UiO-66-NH2/MCA/MWCNT@rGONR nanocomposite

In this work, we designed and synthesized a nanocomposite of amine-functionalized metal organic framework (UiO-66-NH2), multiwalled carbon nanotube@reduced graphene oxide nanoribbon (MWCNT@rGONR) and a covalent organic framework (COF) synthesized by melamine and cyanutic acidmonomers through polycondensation (represented by MCA). The UiO-66-NH2/MCA/MWCNT@rGONR nanocomposite was used as a sensitive platform for an electrochemical aptasensor to detect kanamycin (kana). Owning to the rich chemical functionality, amino-rich structure and excellent electrochemical activity, the cDNA strands terminated by amino, can not only anchor over the UiO-66-NH2/MCA/MWCNT@rGONR surface but also can penetrate into the interior of porous UiO-66-NH2/MCA/MWCNT@rGONR networks. The characterization of UiO-66-NH2/MCA/MWCNT@rGONR nanocomposite was performed by scanning electronic microscopy (SEM), X-ray photoelectron spectroscopy (XPS), fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). Furthermore, cyclic voltammetry (CV) and square wave voltammetry (SWV) were employed for the electrochemical performance study of this biosensor. According to the results, UiO-66-NH2/MCA/ MWCNT@rGONR nanocomposite exhibited high bioaffinity toward the aptamer, and the lowest limit of detection at 13 nM (S/N = 3) within a linearity of the kana concentration of 25~900 nM. In addition, it possessed great repeatability, stability and selectivity and obtained satisfactory recovery results in real analysis of fish meat and milk, indicating the great potential for analytical measurements in food safety.