title: Concatemeric dsDNA-templated copper nanoparticles strategy with improved sensitivity and stability based on rolling circle replication and its application in microRNA detection.
abstract: 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 500-650 nm under a 340 nm excitation. In comparison with monomeric dsDNA-CuNPs, the sensitivity of concatemeric dsDNA-CuNPs was greatly improved with ~10,000 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.
authors: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Institute of Biology, Hunan University , Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Changsha 410082, China.
authors: Fengzhou
authors: F
authors: Xu
authors: Hui
authors: H
authors: Shi
authors: Xiaoxiao
authors: X
authors: He
authors: Kemin
authors: K
authors: Wang
authors: Dinggeng
authors: D
authors: He
authors: Qiuping
authors: Q
authors: Guo
authors: Zhihe
authors: Z
authors: Qing
authors: Lv'an
authors: L
authors: Yan
authors: Xiaosheng
authors: X
authors: Ye
authors: Duo
authors: D
authors: Li
authors: Jinlu
authors: J
authors: Tang
mesh_terms: D003300:Copper / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D017931:DNA Primers; D004261:DNA Replication; D004270:DNA, Circular / Q000737:chemistry; D044708:DNA, Concatenated / Q000737:chemistry; D005456:Fluorescent Dyes; D053768:Metal Nanoparticles / Q000737:chemistry*; D035683:MicroRNAs / Q000032:analysis*; D012680:Sensitivity and Specificity
chemical_list: D017931:DNA Primers; D004270:DNA, Circular; D044708:DNA, Concatenated; D005456:Fluorescent Dyes; D035683:MicroRNAs; C487931:mirnlet7 microRNA, human; D003300:Copper; D004247:DNA