Concatemeric dsDNA-Templated Copper Nanoparticles Strategy with Improved Sensitivity and Stability Based on Rolling Circle Replication and Its Application in MicroRNA Detection

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• 作者：Fengzhou Xu ; Hui Shi ; Xiaoxiao He ; Kemin Wang ; Dinggeng He ; Qiuping Guo ; Zhihe Qing ; Lv鈥檃n Yan ; Xiaosheng Ye ; Duo Li ; Jinlu Tang
• 刊名：Analytical Chemistry
• 出版年：2014
• 出版时间：July 15, 2014
• 年：2014
• 卷：86
• 期：14
• 页码：6976-6982
• 全文大小：443K
• ISSN：1520-6882

文摘

DNA-templated copper nanoparticles (CuNPs) have emerged as promising fluorescent probes for biochemical assays, but the reported monomeric CuNPs remain problematic because of weak fluorescence and poor stability. To solve this problem, a novel concatemeric dsDNA-templated CuNPs (dsDNA-CuNPs) strategy was proposed by introducing the rolling circle replication (RCR) technique into CuNPs synthesis. In this strategy, a short oligonucleotide primer could trigger RCR and be further converted to a long concatemeric dsDNA scaffold through hybridization. After the addition of copper ions and ascorbate, concatemeric dsDNA-CuNPs could effectively form and emit intense fluorescence in the range of 500鈥?50 nm under a 340 nm excitation. In comparison with monomeric dsDNA-CuNPs, the sensitivity of concatemeric dsDNA-CuNPs was greatly improved with 10鈥?00 folds amplification. And their fluorescence signal was detected to reserve 60% at 2.5 h after formation, revealing 2 times enhanced stability. On the basis of these advantages, microRNA let-7d was selected as the model target to testify this strategy as a versatile assay platform. By directly using let-7d as the primer in RCR, the simple, low-cost, and selective microRNA detection was successfully achieved with a good linearity between 10 and 400 pM and a detection limit of 10 pM. The concatemeric dsDNA-CuNPs strategy might be widely adapted to various analytes that can directly or indirectly induce RCR.