期刊
ANALYST
卷 138, 期 17, 页码 4818-4822出版社
ROYAL SOC CHEMISTRY
DOI: 10.1039/c3an00757j
关键词
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资金
- NNSF of China [21275119, 21075100, 21105081]
- State Key Laboratory of Electroanalytical Chemistry [SKLEAC2010009]
- Postgraduate Science and Technology Innovation Program of Southwest China University [KB2010006, KB2011011]
- Fundamental Research Funds for the Central Universities [XDJK2012A004]
- Natural Science Foundation of Chongqing City [CSTC-2011BA7003, CSTC-2009BA1003]
- Specialized Research Fund for the Doctoral Program of Higher Education [20100182110015]
In the present study, an ultrasensitive electrochemical aptasensor for the simultaneous detection of thrombin (TB) and ochratoxin A (OTA) was fabricated by using exonuclease-catalyzed target recycling and DNA concatemers for signal amplification. The previously hybridized double-stranded DNAs (SH-cTBA/TBA and SH-cOBA/OBA) were self-assembled on a gold electrode. In the presence of targets, the formation of aptamer-target complexes would lead to not only the dissociation of aptamers (TBA and OBA) from the double-stranded DNAs but also the transformation of the complementary DNAs (SH-cTBA and SH-cOBA) into hairpin structures. Subsequently, owing to employment of RecJf exonuclease, which is a single-stranded DNA-specific exonuclease to selectively digest the appointed DNAs (TBA and OBA), the targets could be liberated from the aptamer-target complexes for recycling of the analytes. Thereafter, probe DNAs (T1 and T2) were employed to hybridize with SH-cTBA and SH-cOBA respectively to provide primers for the concatemer reaction. After that, when four auxiliary DNA strands S1, anthraquinone-2-carboxylic acid (AQ)-labeled S2, S3, S4, as well as hemin were introduced, extended dsDNA polymers with lots of AQ moieties and hemin-G-quadruplex complexes could form on the electrode surface. Then, based on the signal of the AQ and hemin-G-quadruplex complex, an electrochemical aptasensor for the simultaneous detection of TB and OTA was successfully fabricated.
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