Aim and Background: Diarrhea is the second main cause of mortality in the world that produced by vibrio cholera. Vibrio cholera is the important microorganism related with pandemic and epidemic cholera outbreaks. Detection in the early stage is considered to prevent the distribution of disease. Cholera toxin (CT) is the major virulence factor of disease.  Aptamers have emerged as highly efficient agents for the specific detection and binding of bacterial targets. These versatile molecules offer a promising alternative to antibodies, finding applications in biomarker discovery, diagnosis, imaging, and targeted therapy. They are produced by asymmetric PCR and selected through the Systematic Evolution of Ligands by Exponential Enrichment (SELEX).

 Material and Methods:  In this study, aptamers generated by asymmetric PCR were utilized, after running 11 rounds of SELEX, numerous aptamers were selected and evaluated using ELASA to check their binding to CtxB and similar proteins.

Results: Appropriate aptamers were isolated and sequenced. Then the best aptamer with the highest affinity to CtxB (amount of OD was 1.8) and the least cross-reactivity to similar proteins were separated. Bioinformatics studies for this aptamer show the proper interaction between the aptamer and the CtxB.