title: Novel strategy combining SYBR Green I with carbon nanotubes for highly sensitive detection of Salmonella typhimurium DNA.
abstract: A simple, selective, sensitive and label-free fluorescent method for detecting trpS-harboring Salmonella typhimurium was developed in this study. This assay used the non-covalent interaction of single-stranded DNA (ssDNA) probes with SWNTs, since SWNTs can quench fluorescence. Fluorescence recovery (78% with 1.8 nM target DNA) was detected in the presence of target DNA as ssDNA probes detached from SWNTs hybridized with target DNA, and the resulting double-stranded DNA (dsDNA) intercalated with SYBR Green I (SG) dyes. The increasing fluorescence intensity reached 4.54-fold. In contrast, mismatched oligonucleotides (1- or 3-nt difference to the target DNA) did not contribute to significant fluorescent recovery, which demonstrated the specificity of the assay. The increasing fluorescence intensity increased 3.15-fold when purified PCR products containing complementary sequences of trpS gene were detected. These results confirmed the ability to use this assay for detecting real samples.
authors.affiliation: The Co-construction Laboratory of Microbial Molecular Biology of Province and Ministry of Science and Technology, College of Life Science, Hunan Normal University, Changsha, Hunan, People's Republic of China.
authors.forename: Pingdao
authors.initials: P
authors.lastname: Mao
authors.forename: Yi
authors.initials: Y
authors.lastname: Ning
authors.forename: Wenkai
authors.initials: W
authors.lastname: Li
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Peng
authors.forename: Yongzhe
authors.initials: Y
authors.lastname: Chen
authors.forename: Le
authors.initials: L
authors.lastname: Deng
mesh_terms: D001483:Base Sequence; D052160:Benzothiazoles; D004269:DNA, Bacterial / Q000032:analysis* / Q000235:genetics*; D003959:Diamines; D005456:Fluorescent Dyes; D005798:Genes, Bacterial; D037742:Nanotubes, Carbon; D015345:Oligonucleotide Probes / Q000235:genetics; D009930:Organic Chemicals; D011804:Quinolines; D012486:Salmonella typhimurium / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D012703:Serotyping / Q000379:methods; D013050:Spectrometry, Fluorescence
chemical_list: D052160:Benzothiazoles; D004269:DNA, Bacterial; D003959:Diamines; D005456:Fluorescent Dyes; D037742:Nanotubes, Carbon; D015345:Oligonucleotide Probes; D009930:Organic Chemicals; D011804:Quinolines; C098022:SYBR Green I
keywords: EB; Nucleic acid detection; SG; SWNTs; SYBR Green I; Salmonella typhimurium; double-stranded DNA; dsDNA; ethidium bromide; nIR; near-infrared; single wall carbon nanotubes; single-stranded DNA; ssDNA