title: Label-free and high-sensitive detection of Salmonella using a surface plasmon resonance DNA-based biosensor.
abstract: A method based on surface plasmon resonance (SPR) DNA biosensor has been developed for label-free and high-sensitive detection of Salmonella. A biotinylated single-stranded oligonucleotide probe was designed to target a specific sequence in the invA gene of Salmonella and then immobilized onto a streptavidin coated dextran sensor surface. The invA gene was isolated from bacterial cultures and amplified using a modified semi-nested asymmetric polymerase chain reaction (PCR) technique. In order to investigate the hybridization detection, experiments with different concentration of synthetic target DNA sequences have been performed. The calibration curve of synthetic target DNA had good linearity from 5 nM to 1000 nM with a detection limit of 0.5 nM. The proposed method was applied successfully to the detection of single-stranded invA amplicons from three serovars of Salmonella, i.e., Typhimurium, Enterica and Derby, and the responses to PCR products were related to different S. typhimurium concentrations in the range from 10(2) to 10(10) CFU mL(-1). While with this system to detect E. coli and S. aureus, no significant signal was observed, demonstrating good selectivity of the method. In addition, the hybridization can be completed within 15 min, and the excellent sensor surface regeneration allows at least 300 assay cycles without obvious loss of performance.
authors.affiliation: Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), Department of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China.
authors.forename: Decai
authors.initials: D
authors.lastname: Zhang
authors.forename: Yurong
authors.initials: Y
authors.lastname: Yan
authors.forename: Qing
authors.initials: Q
authors.lastname: Li
authors.forename: Tianxiao
authors.initials: T
authors.lastname: Yu
authors.forename: Wei
authors.initials: W
authors.lastname: Cheng
authors.forename: Long
authors.initials: L
authors.lastname: Wang
authors.forename: Huangxian
authors.initials: H
authors.lastname: Ju
authors.forename: Shijia
authors.initials: S
authors.lastname: Ding
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D015169:Colony Count, Microbial / Q000295:instrumentation*; D004247:DNA / Q000235:genetics*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D012475:Salmonella / Q000235:genetics* / Q000302:isolation & purification*; D012680:Sensitivity and Specificity; D013194:Staining and Labeling; D020349:Surface Plasmon Resonance / Q000295:instrumentation*
chemical_list: D004247:DNA