Hairpin Assembly Amplified Electrochemical Biosensor for Highly Sensitive and Specific Detection of DNA

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• 作者：Changli Zhong ; Gang Yang ; Nian Wang ; Feihu Ji ; Ye Zhang ; Xiaojuan Ding ; Junhong Yang and Jian Zhang
• 刊名：Electroanalysis
• 出版年：2016
• 出版时间：July 2016
• 年：2016
• 卷：28
• 期：7
• 页码：1578-1583
• 全文大小：881K
• ISSN：1521-4109

文摘

In this report, a simple electrochemical biosensor has been developed for highly sensitive and specific detection of DNA based on hairpin assembly amplification. In the presence of target DNA, the biotin-labelled hairpin H1 is opened by hybridizing with target DNA through complementary sequences. Then the opened hairpin H1 assembles with the hairpin H2 to displace the target DNA, generating H1-H2 complex. The displaced target DNA could trigger the next cycle of hairpins assembly, resulting in the generation of numerous H1-H2 complexes. Subsequently, the H1-H2 complex hybridizes with the capture probe immobilized on the electrode. Finally, the streptavidin alkaline phosphatase (ST-ALP) binds to biotin in the capture probe-H1-H2 complex and catalyzes the substrate α-naphthol (α-NP) to produce electrochemical signal. To make a more fascinating hairpin assembly amplification strategy in signal amplification, mismatched base sequences are designed in hairpin H2 to decrease non-specific binding of the hairpin substrates. The developed biosensor achieves a sensitivity of 20 pM with a linear range from 25 pM to 25 nM, and shows high selectivity toward single-base mismatch. Thus, the proposed electrochemical biosensor might have the potential for early clinical diagnosis and therapy.