title: A novel fluorescent DNA sensor for ultrasensitive detection of Helicobacter pylori.
abstract: In this work, a novel fluorescent DNA sensor for ultrasensitive detection of Helicobacter pylori (H. pylori) DNA was developed. This strategy took advantage of DNA hybridization between single-stranded DNA (ssDNA, which had been designed as an aptamer specific for H. pylori DNA) and the complementary target H. pylori DNA, and the feature that ssDNA bound to graphene oxide (GO) with significantly higher affinity than double-stranded DNA (dsDNA). ssDNA were firstly covalent conjugated with CuInS2quantum dots (QDs) by reaction between the carboxy group of QDs and amino group modified ssDNA, forming ssDNA-QDs genosensor. In the absence of the complementary target H. pylori DNA, GO could adsorb ssDNA-QDs DNA sensor and efficiently quench the fluorescence of ssDNA-QDs. While the complementary target H. pylori DNA was introduced, the ssDNA-QDs preferentially bound with the H. pylori DNA. The formation of dsDNA would alter the conformation of ssDNA and disturb the interaction between ssDNA and GO. Thus, the dsDNA-QDs/GO system exhibited a stronger fluorescence emission than that of the ssDNA-QDs/GO system. Under the optimized conditions, a linear correlation was established between the fluorescence intensity ratio I/I0and the concentration of H. pylori DNA in the range of 1.25-875pmolL-1with a detection limit of 0.46pmolL-1. The proposed method was applied to the determination of H. pylori DNA sequence in milk samples with satisfactory results.
authors: Department of Analytical Chemistry, College of Chemistry, Jilin University, Changchun, 130012 China.
authors: Ziping
authors: Z
authors: Liu
authors: Department of Analytical Chemistry, College of Chemistry, Jilin University, Changchun, 130012 China. Electronic address: suxg@jlu.edu.cn.
authors: Xingguang
authors: X
authors: Su
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000379:methods*; D004269:DNA, Bacterial / Q000032:analysis*; D004277:DNA, Single-Stranded / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry; D006108:Graphite / Q000737:chemistry*; D016481:Helicobacter Infections / Q000382:microbiology; D016480:Helicobacter pylori / Q000302:isolation & purification*; D006801:Humans; D057230:Limit of Detection; D008892:Milk / Q000382:microbiology*; D009693:Nucleic Acid Hybridization / Q000379:methods; D010087:Oxides / Q000737:chemistry; D045663:Quantum Dots / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods
chemical_list: D004269:DNA, Bacterial; D004277:DNA, Single-Stranded; D005456:Fluorescent Dyes; D010087:Oxides; D006108:Graphite
keywords: DNA sensor; Fluorescence; Helicobacter pylori; QDs, Graphene oxide