title: A novel FRET-based optical fiber biosensor for rapid detection of Salmonella typhimurium.
abstract: A biosensor that is portable and permits on-site analysis of samples would significantly reduce the large economical burden of food products recalls. A fiber optic portable biosensor utilizing the principle of fluorescence resonance energy transfer (FRET) was developed for fast detection of Salmonella typhimurium (S. typhimurium) in ground pork samples. Labeled antibody-protein G complexes were formed via the incubation of anti-Salmonella antibodies labeled with FRET donor fluorophores (Alexa Fluor 546) and protein G (PG) labeled with FRET acceptor fluorophores (Alexa Fluor 594). Utilizing silanization, the labeled antibodies-PG complexes were then immobilized on decladded, tapered silica fiber cores to form the evanescent wave-sensing region. The biosensors were tested in two different solutions: (1) PBS doped with S. typhimurium and (2) homogenized pork sample with S. typhimurium. The fiber probes tested in a S. typhimurium doped phosphate buffered solution demonstrated the feasibility of the biosensor for detecting S. typhimurium as well as determined the optimal packing density of the labeled antibody-PG complexes on the surface of fibers. The results showed that a packing density of 0.033 mg/ml produced the lowest limit of detection of 10(3)cells/ml with 8.2% change in fluorescence. The fiber probes placed in homogenized pork samples inoculated with S. typhimurium showed a limit of detection of 10(5)CFU/g with a 6.67% in fluorescence within a 5-min response time. These results showed that the FRET-based fiber optic biosensor can become a useful analytical tool for detection of S. typhimurium in real food samples.
authors.affiliation: Department of Biological Engineering, 250 Ag. Engineering Bldg., University of Missouri, Columbia, MO 65211, USA.
authors.forename: Sungho
authors.initials: S
authors.lastname: Ko
authors.forename: Sheila A
authors.initials: SA
authors.lastname: Grant
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D015169:Colony Count, Microbial / Q000295:instrumentation* / Q000379:methods; D005336:Fiber Optic Technology / Q000295:instrumentation; D031541:Fluorescence Resonance Energy Transfer / Q000295:instrumentation* / Q000379:methods; D005504:Food Analysis / Q000295:instrumentation* / Q000379:methods; D005506:Food Contamination / Q000032:analysis*; D007118:Immunoassay / Q000295:instrumentation / Q000379:methods; D008460:Meat / Q000382:microbiology*; D009862:Online Systems; D055100:Optical Fibers; D012486:Salmonella typhimurium / Q000276:immunology / Q000302:isolation & purification*; D013552:Swine