In this work, we designed and synthesized a nanocomposite comprising an amine-functionalized metal organic framework (UiO-66-NH2), a multiwalled carbon nanotube@reduced graphene oxide nanoribbon (MWCNT@rGONR) and a covalent organic framework (COF) synthesized using melamine and cyanuric acidmonomers via 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). Owing to the rich chemical functionality, amino-rich structure and excellent electrochemical activity, the cDNA strands with terminal amino groups can not only anchor over the UiO-66-NH2/MCA/MWCNT@rGONR surface but also penetrate into the interior of porous UiO-66-NH2/MCA/MWCNT@rGONR networks. The characterization of the UiO-66-NH2/MCA/MWCNT@rGONR nanocomposite was performed by scanning electronic microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR) spectroscopy and X-ray diffraction (XRD). Furthermore, cyclic voltammetry (CV) and square wave voltammetry (SWV) were employed for the electrochemical performance study of this biosensor. The results indicated that the 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 the real analysis of fish meat and milk, indicating the great potential for analytical measurements in food safety.
Xin Yao,Liyu Yang,Siyi Yang,Jinhui Shen,Danqun Huo,Huanbao Fa,Changjun Hou,Mei Yang
A Ti3C2Tx/MoS2/MWCNT@rGONR nanocomposite was prepared for the first time for building a sensitive electrochemical aptasening platform to simultaneously detect kanamycin (Kana) and chloramphenicol (Cap). Owing to their accordion-like structure, rich surface groups, and high charge mobility, Ti3C2Tx/MoS2/MWCNT@rGONR composites provided a spacious covalent immobilization surface and a better electrochemical aptasensing platform. The aptamers of Kana and Cap used in sensors enhance the selectivity. Furthermore, TiP, an ion exchanger, was used for loading more different metal ions functioning as labels to form a sandwich-type sensor together with Ti3C2Tx/MoS2/MWCNT@rGONR, improving the electrochemical sensitivity and obtaining a highly distinguishable signal readout. Under the optimized conditions, the sensor has good detection limits of 0.135 nmol L−1 and 0.173 nmol L−1 for Kana and Cap, respectively, at the same linearity concentration of 0.5–2500 nmol L−1. Finally, it was successfully applied for detection in milk and fish meat, and the results were compared with the standard method HPLC, indicating its great potential for food safety monitoring.
Qingyan Liu,Jing Bao,Mei Yang,Xiaojing Wang,Shiyu Lan,Changjun Hou,Yongzhong Wang,Huanbao Fa
In this work, a multiwalled carbon [email protected] graphene oxide nanoribbons core-shell heterostructure ( [email protected] )-modified glassy carbon electrode ( [email protected] /GCE) was employed to electrochemically detect glutathione (GSH). The morphologies and microstructures of the as-prepared [email protected] heterostructure were examined by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy spectrum (FT-IR), respectively. The electrochemical characteristics and catalytic behaviors of the fabricated sensor for determination of GSH were systematically investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), differential pulse voltammetry (DPV), and amperometry (i–t). Under optimum conditions, the [email protected] heterostructure modified electrode possesses the ability of strong electrocatalytic for GSH with high selectivity and sensitivity, fast response, wide linear range, low detection limit (39 nM) and outstanding reproducibility. Its further application for the quantification of GSH concentration in human serum samples was also demonstrated with satisfactory accuracy. These features indicate that the prepared core-shell [email protected] heterostructure with unique electronic structure offers an excellent biosensing platform for sensitive and selective detection of glutathione.
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