Electrochemical Detection of Peanut Allergen Ara h 1 Using a Sensitive DNA Biosensor Based on Stem鈥揕oop Probe

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• 作者：Xiulan Sun ; Lu Guan ; Xiaohong Shan ; Yinzhi Zhang ; Zaijun Li
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2012
• 出版时间：November 7, 2012
• 年：2012
• 卷：60
• 期：44
• 页码：10979-10984
• 全文大小：328K
• 年卷期：v.60,no.44(November 7, 2012)
• ISSN：1520-5118

文摘

A novel electrochemical DNA sensor was developed by using a stem鈥搇oop probe for peanut allergen Ara h 1 detection. The probe was modified with a thiol at its 5鈥?end and a biotin at its 3鈥?end. The biotin-tagged 鈥渕olecular beacon鈥?like probe was attached to the surface of a gold electrode to form a stem鈥搇oop structure by self-assembly through facile gold鈥搕hiol affinity. 6-Mercaptohexanol (MCH) was used to cover the remnant bare region. The stem鈥?loop probe was 鈥渃losed鈥?when the target was absent, and then the hybridization of the target induced the conformational change to 鈥渙pen鈥? along with the biotin at its 3鈥?end moved away from the electrode surface. The probe conformational change process was verified by circular dichroism (CD); meanwhile, electron-transfer efficiency changes between probe and electrode were proved by electrochemical impedance spectroscopy (EIS). The detection limit of this method was 0.35 fM with the linear response ranging from 10^鈥?5 to 10^鈥?0 M. Moreover, a complementary target could be discriminated from one-base mismatch and noncomplementarity. The proposed strategy has been successfully applied to detect Ara h 1 in the peanut DNA extracts of peanut milk beverage, and the concentration of it was 3.2 脳 10^鈥?3 mol/L.

Keywords:

peanut allergen; Ara h 1; stem鈭抣oop probe; electrochemical impedance spectroscopy (EIS); charge transfer resistance (Rct)