An electrochemical biosensor based on hairpin-DNA aptamer probe and restriction endonuclease for ochratoxin A detection

作者：Zhang, Jing; Chen, Jinghua^*; Zhang, Xi; Zeng, Zhigao; Chen, Mei; Wang, Shihua

来源：Electrochemistry Communications, 2012, 25: 5-7.

DOI：10.1016/j.elecom.2012.09.006

• Hairpin-DNA
• Restriction endonuclease
• OTA
• Aptamer

A new electrochemical DNA biosensor based on hairpin anti-ochratoxin A (OTA) aptamer and site-specific DNA cleavage of restriction endonuclease Taqal was reported in this paper. Taqal is able to specifically cleave only double strand DNA, but not single strand DNA. The hairpin-DNA aptamer probe (Hap), thiolated single strand DNA labeled with biotin group, was immobilized on a gold electrode. In the presence of OTA, Hap bind with OTA to form Hap-OTA G-quadruplex. Meanwhile, the stem of Hap, which contains a Taqal recognition site, is opened to form single strand and resistant to the cleavage of Taqal. After reaction with the streptavidin-HRP, the resulting HRP-tagged Hap-OTA can effectively catalyze the hydrogen peroxide (H2O2)-mediated oxidation of 3,3',5,5'-tetramethylbenzidine sulfate (TMB), accompanied by a change from colorless to blue in solution color and an increased electrochemical current signal. However, in the absence of OTA, the biotin group of the Hap can be easily cleaved by Taqal due to the double-stranded stem, which makes the streptavidin-HRP cannot bind with the Hap and increase electrochemical current signal. By employing the above strategy, this DNA biosensor can detect as low as 0.4 pg/mL OTA with ultrahigh selectivity.

• 出版日期2012-11
• 单位福建农林大学; 福建医科大学