Selection, identification, and application of dual DNA aptamers against Shigella sonnei

Abstract

Shigella sonnei is a highly contagious and harmful pathogenic type of entero bacteria that is a significant threat to public health around the world. In this study, aptamers with improved affinity and specificity were screened through twelve selection rounds based on whole-bacterium systematic evolution of ligands by exponential enrichment (SELEX). After cloning and sequencing, thirty sequences were obtained and nine aptamers were selected for affinity and specificity assays. According to the flow cytometric assessment, the dissociation constant (K_d) values for specific binding of the aptamers Sp1 and Sp20 to S. sonnei were 5.980 ± 0.835 nM and 14.32 ± 2.19 nM, respectively. A sensitive sandwich detection method using the dual aptamers Sp1 and Sp20 was developed to recognize S. sonnei. This method achieved a detection limit of 30 cfu mL⁻¹. This study demonstrates that the selected dual aptamers have potential application for S. sonnei detection.