期刊
TALANTA
卷 103, 期 -, 页码 14-19出版社
ELSEVIER
DOI: 10.1016/j.talanta.2012.09.048
关键词
Click chemistry; Azido-aptamer; Impedimetric aptasensor; Ochratoxine A; Beer sample
资金
- Higher Education Commission of Pakistan
- IMHOTEP
The aptamer immbolization onto organized mixed layers of diazonium salts via click chemistry was explored. The immobilized aptamer was employed in the fabrication of a highly sensitive and reusable electrochemical impedimetric aptasensor for the detection of ochratoxin A (OTA). The screen-printed carbon electrodes (SPCEs) were first modified by electrografting of a protected 4-((trimethylsilyl)ethynyl) benzene (TMSi-Eth-Ar) layer followed by a second one of p-nitrobenzene (p-NO2-Ar) by means of electrochemical reduction of their corresponding diazonium salts, (TMSi-Eth-Ar-N-2(+)) and (P-NO2-ArN2+). After deprotection, a layer with active ethynyl groups was obtained. In the presence of copper (I) catalyst, the ethynyl groups reacted efficiently with aptamer bearing an azide function, thus forming a covalent 1,2,3-triazole linkage. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in the presence of ferri/ferrocyanide redox probe [Fe(CN)(6)](4-/3-) were used to characterize each step in the aptasensor development. The increase in electron-transfer resistance (R-et) values due to the specific aptamer-OTA interaction was proportional to the concentration of OTA in a range between 1.25 ng/L and 500 ng/L, with a detection limit of 0.25 ng/L. (C) 2012 Elsevier B.V. All rights reserved.
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