An aptamer-based PCR method coupled with magnetic immunoseparation for sensitive detection of Salmonella Typhimurium in ground turkey

Abstract Aptamers are single-stranded oligonucleotide ligands that can bind to targets with high affinity and specificity. They have been widely studied in the field of diagnostics as alternatives to antibodies due to their favorable features such as easy labeling, temperature tolerance, lower cost and recognition of a wide variety of targets. In this study, an aptamer-based PCR method coupled with magnetic immunoseparation was developed to detect S. Typhimurium from ground turkey. Firstly, biotinylated polyclonal anti- S . Typhimurium antibody was immobilized on streptavidin-coated magnetic nanobeads to capture S . Typhimurium. Secondly, the aptamers were added and bound to the surface of S . Typhimurium after blocking the magnetic nanobeads with short ssDNA. Finally, the aptamers were released by heating and amplified by PCR. After optimization, this assay was able to detect 10 2  CFU/mL of S. Typhimurium in pure culture, and 10 3  CFU/mL of S. Typhimurium in ground turkey. This study demonstrated the feasibility and application of an aptamer-based PCR method coupled with magnetic immunoseparation for sensitive detection of S . Typhimurium in ground turkey.