Rapid colorimetric detection of Salmonella typhimuriumusing a selective filtration technique combined with antibody–magnetic nanoparticle nanocomposites

• Published in: Analytical and bioanalytical chemistry Vol. 406; no. 3; pp. 859 - 866
• Main Authors: Shim, Won-Bo, Song, Jeong-Eon, Mun, Hyoyoung, Chung, Duck-Hwa, Kim, Min-Gon
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 2014; Springer Nature B.V
• Subjects: Analytical Chemistry; Antibodies, Monoclonal - metabolism; Bacteria; Bacterial Typing Techniques - methods; Biochemistry; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Colorimetry - methods; Computed tomography; Consumer products; Filtration; Food Science; Humans; Laboratory Medicine; Limit of Detection; Metal Nanoparticles - chemistry; Monitoring/Environmental Analysis; Nanocomposites - chemistry; Preservatives; Reproducibility of Results; Research Paper; Salmonella; Salmonella typhimurium - isolation & purification; Time Factors; Selective filtration; Antibody–magnetic nanoparticle; Colorimetric detection
• DOI: 10.1007/s00216-013-7497-6
• ISSN: 1618-2642

Detection of pathogenic bacteria that pose a great risk to human health requires a rapid, convenient, reliable, and sensitive detection method. In this study, we developed a selective filtration method using monoclonal antibody (MAb)–magnetic nanoparticle (MNP) nanocomposites for the rapid and sensitive colorimetric detection of Salmonella typhimurium . The method contains two key steps: the immunomagnetic separation of the bacteria using MAb–MNP nanocomposites and the filtration of the nanocomposite-bound bacteria. Color signals from the nanocomposites remaining on the membrane were measured, which reflected the amount of bacteria in test samples. Immunomagnetic capture efficiencies of 8 to 90 % for various concentrations of the pathogen (2 × 10 4 –2 × 10 1 cells) were obtained. After optimization of the method, 2 × 10 1 cells of S. typhimurium in pure culture solution was detectable as well as in artificially inoculated vegetables (100 cells/g). The method was confirmed to be highly specific to S. typhimurium without cross-reaction to other pathogenic bacteria and could be concluded within 45 min, yielding results in a shorter or similar time period as compared with recently reported antibody immobilized on magnetic-particle-based methods. This study also demonstrated direct application of MAb–MNP nanocomposites without a dissociation step of bacteria from magnetic beads in colorimetric assays in practice.