title: DNA biosensor-based on fluorescence detection of E. coli O157:H7 by Au@Ag nanorods.
abstract: A novel DNA sensor for the detection of the Escherichia coli O157:H7 (E. coli O157:H7) eaeA gene was constructed using surface enhanced fluorescence (SEF). The spacing distance dependence nature of Au@Ag nanorods surface enhanced fluorescence was investigated when the cy3-labled single strand DNA(ssDNA) and the stem-loop DNA probe modified on the nanorods was co-hybridized. The result revealed that the fluorescence intensity reached the maximum value with the spacing distance of about 10nm between cy3 and the Au@Ag nanorods surface. Based on this result, a fluorescence "ON/OFF" switch for detecting the eaeA gene of E. coli O157:H7 was constructed. Under optimal conditions, the DNA sensor produced a linear range from 10(-17) to 10(-11) M with a correlation coefficient of 0.9947 and a detection limit of 3.33×10(-18) M, and was also found to be specific in targeting eaeA. The DNA sensor demonstrated a new strategy of combining eaeA recognition and Au@Ag nanorods for fluorescence signal enhancement, and increased sensitivity in the detection of bacterial specific genes.
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, Jiangsu 7214122, PR China.
authors.forename: Jiadi
authors.initials: J
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, Jiangsu 7214122, PR China.
authors.forename: Jian
authors.initials: J
authors.lastname: Ji
authors.affiliation: School of Physics and Telecommunication Engineering, Shaanxi University of Technology, Hanzhong 723000, PR China.
authors.forename: Yanqing
authors.initials: Y
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, Jiangsu 7214122, PR China.
authors.forename: Mandour H
authors.initials: MH
authors.lastname: Abdalhai
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, Jiangsu 7214122, PR China.
authors.forename: Yinzhi
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, Jiangsu 7214122, PR China. Electronic address: sxlzzz@jiangnan.edu.cn.
authors.forename: Xiulan
authors.initials: X
authors.lastname: Sun
mesh_terms: D018829:Adhesins, Bacterial / Q000032:analysis* / Q000235:genetics; D015342:DNA Probes / Q000737:chemistry* / Q000235:genetics; D004269:DNA, Bacterial / Q000032:analysis* / Q000737:chemistry / Q000235:genetics; D019453:Escherichia coli O157 / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*; D029968:Escherichia coli Proteins / Q000032:analysis* / Q000235:genetics; D006046:Gold / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D043942:Nanotubes / Q000737:chemistry / Q000648:ultrastructure; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012834:Silver / Q000737:chemistry; D013050:Spectrometry, Fluorescence / Q000379:methods*
chemical_list: D018829:Adhesins, Bacterial; D015342:DNA Probes; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; C073819:eaeA protein, E coli; D012834:Silver; D006046:Gold
keywords: Au@Ag nanorods; Escherichia coli O157:H7; Surface enhanced fluorescence DNAsensor