title: Gold nanoparticle-based enzyme-linked antibody-aptamer sandwich assay for detection of Salmonella Typhimurium.
abstract: Enzyme-linked immunosorbent assay (ELISA) provides a convenient means for the detection of Salmonella enterica serovar Typhimurium (STM), which is important for rapid diagnosis of foodborne pathogens. However, conventional ELISA is limited by antibody-antigen immunoreactions and suffers from poor sensitivity and tedious sample pretreatment. Therefore, development of novel ELISA remains challenging. Herein, we designed a comprehensive strategy for rapid, sensitive, and quantitative detection of STM with high specificity by gold nanoparticle-based enzyme-linked antibody-aptamer sandwich (nano-ELAAS) method. STM was captured and preconcentrated from samples with aptamer-modified magnetic particles, followed by binding with detector antibodies. Then nanoprobes carrying a large amount of reporter antibodies and horseradish peroxidase molecules were used for colorimetric signal amplification. Under the optimized reaction conditions, the nano-ELAAS assay had a quantitative detection range from 1 × 10(3) to 1 × 10(8) CFU mL(-1), a limit of detection of 1 × 10(3) CFU mL(-1), and a selectivity of >10-fold for STM in samples containing other bacteria at higher concentration with an assay time less than 3 h. In addition, the developed nanoprobes were improved in terms of detection range and/or sensitivity when compared with two commercial enzyme-labeled antibody signal reporters. Finally, the nano-ELAAS method was demonstrated to work well in milk samples, a common source of STM contamination.
authors.affiliation: Key Laboratory of Laboratory Medicine, Ministry of Education, Zhejiang Provincial Key Laboratory of Medical Genetics, Wenzhou Medical University , Wenzhou 325035, Zhejiang, China.
authors.forename: Wenhe
authors.initials: W
authors.lastname: Wu
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Dun
authors.initials: D
authors.lastname: Pan
authors.forename: Jiang
authors.initials: J
authors.lastname: Li
authors.forename: Shiping
authors.initials: S
authors.lastname: Song
authors.forename: Mingge
authors.initials: M
authors.lastname: Rong
authors.forename: Zixi
authors.initials: Z
authors.lastname: Li
authors.forename: Jimin
authors.initials: J
authors.lastname: Gao
authors.forename: Jianxin
authors.initials: J
authors.lastname: Lu
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology*; D052157:Aptamers, Nucleotide / Q000276:immunology*; D002138:Calibration; D003124:Colorimetry; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D006046:Gold / Q000737:chemistry*; D006735:Horseradish Peroxidase / Q000378:metabolism; D008163:Luminescent Measurements; D053768:Metal Nanoparticles / Q000737:chemistry*; D008892:Milk / Q000382:microbiology; D012486:Salmonella typhimurium / Q000302:isolation & purification*
chemical_list: D000906:Antibodies; D052157:Aptamers, Nucleotide; D006046:Gold; D006735:Horseradish Peroxidase
keywords: Salmonella Typhimurium; antibody; aptamer; gold nanoparticle; magnetic microparticle; nanoprobe