DNA aptamer identification and characterization for E.?coli O157 detection using cell based SELEX method

摘要

AbstractEscherichia coli (E. coli) O157:H7is a foodborne pathogen that causes symptoms in humans. Its rapid identification should be considered to avoid toxic effects of the pathogen.In this study, systematic evolution of ligands by exponential enrichment using whole cells (Cell-SELEX) method was used for recognizingE.?colistrain, O157 by single-stranded DNA library of aptamer. Nine rounds of cell-selex procedure were applied using O157, as a whole-cell target, with O42, K12, Top10, DH5αE.?colicells,Shigella flexneriandSalmonella typhias counterparts. The specific interaction between selected DNA aptamers and targeted cell was assessed. After applying six rounds of SELEX for selection of DNA aptamers, the candidate sequences were obtained. Finally, specific aptamer was selected as an ideal aptamer for detection and capturing ofE.?coliO157. Dissociation constant of the selected aptamer were calculated (107.6?±?67.8 pM). In addition, the secondary structure prediction and cross reactivity assays were performed. The isolated aptamer efficiency was confirmed and it was shown that the new DNA aptamer sequence has the ability to use for detection. This specific O157:H7 aptamer have the potential for application as a diagnostic ligand and could be used for detection of the related food borne diseases.]]>