Hairpin DNA‐Dependent Click Conjugation of Oligonucleotides for Electrochemical Monitoring of Copper(II) |
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Authors: | Dianyong Tang Jin Zhang Ying Tang Liumei Teng Biyun Xia Dianping Tang |
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Institution: | 1. Chongqing Key Laboratory of Environmental Materials & Remediation Technologies, Chongqing University of Arts and Sciences, Chongqing 402160, P.?R. China;2. Institute of Nanomedicine and Nanobiosensing, Department of Chemistry, Fuzhou University, Fuzhou 350108, P.?R. China |
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Abstract: | A new electrochemical sensing platform was designed for sensitive detection of copper(II) (Cu2+) based on click conjugation of two short oligonucleotides by using methylene blue‐functionalized hairpin DNA as the template. The analyte (Cu2+) was in situ reduced to Cu+ by sodium ascorbate, which catalyzed the click conjugation between two single‐stranded oligonucleotides one was labelled with a 5′‐alkyne and the other with 3′‐azide group via the Cu+‐catalyzed azide‐alkyne cycloaddition. The newly formed long‐chain oligonucleotide induced the conformational change of hairpin DNA to open the hairpin, resulting in methylene blue far away from the electrode for the decrease of redox current. Under optimal conditions, the decrease in the electronic signal was directly proportional to target Cu2+ concentration, and allowed the detection of Cu2+ at a concentration as low as 1.23 nM. Our strategy also displayed high selectivity for Cu2+ against other metal ions owing to the highly specific Cu+‐catalyzed click chemistry reaction, and was applicable for monitoring of Cu2+ in drinking water with satisfactory results. |
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Keywords: | Electrochemical sensor Copper(II) ion Click Conjugation Methylene blue Hairpin DNA |
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