Coupling DNA with enzyme activity: A complex electrochemical sensor with enhanced specificity

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• 作者：Nandi Zhou ; ^{zhounandi@jiangnan.edu.cn" class="auth_mail} ; Yong Liu ; Yuanding You ; Jibao Luo ; Yaping Tian
• 关键词：DNA sensor ; Multi-component analysis ; LDH ; Alternating current voltammetry ; E. coli DNA ligase
• 刊名：Electrochemistry Communications
• 出版年：May, 2014
• 年：2014
• 卷：42
• 期：Complete
• 页码：60-63
• 全文大小：250 K

文摘

We report here an electrochemical sensor which couples the detection of target DNAs with enzyme activity. A hairpin probe DNA complementary to both target DNAs was dually labeled with 5鈥?thiol and 3鈥?methylene blue (MB), and covalently immobilized to gold electrode. In the presence of both target DNAs, the hairpin structure shifted from 鈥渃lose鈥?state to 鈥渙pen鈥?state with the help of Escherichia coli (E. coli) DNA ligase, which can be characterized by alternating current voltammetry (ACV). For target DNA 1 and target DNA 2, the detection limits were 1 nM and 0.25 nM, respectively. Furthermore, the assay was coupled with the activity of lactate dehydrogenase (LDH), which catalyzes the conversion of NADH to NAD⁺. The latter acted as the co-substrate of DNA ligase and produced current change in the presence of both target DNAs. The sensor can analyze the co-existence of multi-components, which efficiently improves the accuracy in the applications such as species identification.