کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1242894 | 1495832 | 2013 | 6 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Highly sensitive ochratoxin A impedimetric aptasensor based on the immobilization of azido-aptamer onto electrografted binary film via click chemistry Highly sensitive ochratoxin A impedimetric aptasensor based on the immobilization of azido-aptamer onto electrografted binary film via click chemistry](/preview/png/1242894.png)
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-N2+) 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 (Ret) 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.
► The SPCE was modified with a robust binary film of diazonium salts.
► Click chemistry was used to immobilize azido-aptamer onto ethynyl modified surface.
► The immobilized aptamer was used in the construction of impedimetric aptasensor for OTA detection.
► The immobilization via click chemistry improved the aptamer binding capacity and magnified the signal response.
Journal: Talanta - Volume 103, 15 January 2013, Pages 14–19