Gold nanoparticle-based colorimetric detection of staphylococcal enterotoxin B using ssDNA aptamers

Staphylococcal enterotoxin (SE) B is one of the most common serotype of SEs to cause staphylococcal food poisoning. To ensure food safety, rapid and low-cost methods have been constantly developed and applied to detect SEB worldwide. In the present investigation, a panel of aptamers of single-stranded DNA molecules against SEB was obtained by optimizing the procedure of systematic evolution of ligands by exponential enrichment, and five of them were selected for further analyzing the characteristics of sequences and second structures. Afterward, an aptamer-based colorimetric method of SEB detection was carried out by employing unmodified gold nanoparticle probes (AuNPs). Results showed that the main second structures of these aptamers were stem loop and hairpin forms. In addition, applying one of these aptamers (No. 15-1), SEB could be detected at the concentration of 10 ng/mL by AuNPs-based colorimetric method. Moreover, the aptamer also possessed a good selectivity toward SEB and SEC1. Our work demonstrated that aptamers had their potential applications as a bioprobe for the detection of SEs in food products.