title: Immuno-capture and in situ detection of Salmonella typhimurium on a novel microfluidic chip.
abstract: The new method presented in this article achieved the goal of capturing Salmonella typhimurium via immunoreaction and rapid in situ detection of the CdSe/ZnS quantum dots (QDs) labeled S. typhimurium by self-assembly light-emitting diode-induced fluorescence detection (LIF) microsystem on a specially designed multichannel microfluidic chip. CdSe/ZnS QDs were used as fluorescent markers improving detection sensitivity. The microfluidic chip developed in this study was composed of 12 sample channels, 3 mixing zones, and 6 immune reaction zones, which also acted as fluorescence detection zones. QDs-IgG-primary antibody complexes were generated by mixing CdSe/ZnS QDs conjugated secondary antibody (QDs-IgG) and S. typhimurium antibody (primary antibody) in mixing zones. Then, the complexes went into immune reaction zones to label previously captured S. typhimurium in the sandwich mode. The capture rate of S. typhimurium in each detection zone was up to 70%. The enriched QDs-labeled S. typhimurium was detected using a self-assembly LIF microsystem. A good linear relationship was obtained in the range from 3.7×10 to 3.7×10(5) cfu mL(-1) using the equation I=0.1739 log (C)-0.1889 with R(2)=0.9907, and the detection limit was down to 37 cfu mL(-1). The proposed method of online immunolabeling with QDs for in situ fluorescence detection on the designed multichannel microfluidic chip had been successfully used to detect S. typhimurium in pork sample, and it has shown potential advantages in practice.
authors.affiliation: College of Chemistry and Chemical Engineering, Chongqing University, No. 174, St. Shazheng, Shapingba District, Chongqing, China. Electronic address: 1058464972@qq.com.
authors.forename: Renjie
authors.initials: R
authors.lastname: Wang
authors.affiliation: College of Chemistry and Chemical Engineering, Chongqing University, No. 174, St. Shazheng, Shapingba District, Chongqing, China. Electronic address: 468885029@qq.com.
authors.forename: Yanan
authors.initials: Y
authors.lastname: Ni
authors.affiliation: College of Chemistry and Chemical Engineering, Chongqing University, No. 174, St. Shazheng, Shapingba District, Chongqing, China; National Center for International Research of Micro/Nano-System and New Material Technology, No. 174, St. Shazhengjie, Shapingba District, Chongqing, China; Key Laboratory of Fundamental Science of Micro/Nano-Device and System Technology for National Defense, Chongqing, China. Electronic address: xuyibbd@sina.com.
authors.forename: Yi
authors.initials: Y
authors.lastname: Xu
authors.affiliation: College of Chemistry and Chemical Engineering, Chongqing University, No. 174, St. Shazheng, Shapingba District, Chongqing, China. Electronic address: 919865356@qq.com.
authors.forename: Yan
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: College of Chemistry and Chemical Engineering, Chongqing University, No. 174, St. Shazheng, Shapingba District, Chongqing, China. Electronic address: 774176325@qq.com.
authors.forename: Chunyan
authors.initials: C
authors.lastname: Dong
authors.affiliation: College of Chemistry and Chemical Engineering, Chongqing University, No. 174, St. Shazheng, Shapingba District, Chongqing, China. Electronic address: 814859441@qq.com.
authors.forename: Na
authors.initials: N
authors.lastname: Chuan
mesh_terms: D000818:Animals; D000906:Antibodies / Q000737:chemistry / Q000276:immunology; D055910:Antibodies, Immobilized / Q000737:chemistry / Q000276:immunology; D005516:Food Microbiology; D007118:Immunoassay / Q000295:instrumentation / Q000379:methods*; D008163:Luminescent Measurements; D008460:Meat / Q000382:microbiology; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation / Q000379:methods*; D045663:Quantum Dots / Q000737:chemistry; D012486:Salmonella typhimurium / Q000276:immunology / Q000302:isolation & purification*; D013552:Swine
chemical_list: D000906:Antibodies; D055910:Antibodies, Immobilized
keywords: In situ detection; Multichannel microfluidic chip; Quantum dots; Salmonella typhimurium; Sel-assembly ligh-emitting diode-induced fluorescence detection microsystem