Direct fluorescence in situ hybridization (FISH) in Escherichia coli with a target-specific quantum dot-based molecular beacon

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• 作者：Sheng-Mei Wu ; Zhi-Quan Tian ; Zhi-Ling Zhang ; Bi-Hai Huang ; Peng Jiang ; Zhi-Xiong Xie ; Dai-Wen Pang
• 关键词：Quantum dot ; Molecular beacon ; β ; -Lactamase ; Escherichia coli ; Fluorescence in situ hybridization (FISH)
• 刊名：Biosensors and Bioelectronics
• 出版年：2010
• 出版时间：15 October 2010
• 年：2010
• 卷：26
• 期：2
• 页码：491-496
• 全文大小：696 K

文摘

Quantum dots (QDs) are inorganic fluorescent nanocrystals with excellent properties such as tunable emission spectra and photo-bleaching resistance compared with organic dyes, which make them appropriate for applications in molecular beacons. In this work, quantum dot-based molecular beacons (QD-based MBs) were fabricated to specifically detect β-lactamase genes located in pUC18 which were responsible for antibiotic resistance in bacteria Escherichia coli (E. coli) DH5α. QD-based MBs were constructed by conjugating mercaptoacetic acid-quantum dots (MAA-QDs) with black hole quencher 2 (BHQ2) labeled thiol DNA vial metal–thiol bonds. Two types of molecular beacons, double-strands beacons and hairpin beacons, were observed in product characterization by gel electrophoresis. Using QD-based MBs, one-step FISH in tiny bacteria DH5α was realized for the first time. QD-based MBs retained their bioactivity when hybridizing with complementary target DNA, which showed excellent advantages of eliminating background noise caused by adsorption of non-specific bioprobes and achieving clearer focus of genes in plasmids pUC18, and capability of bacterial cell penetration and signal specificity in one-step in situ hybridization.