Staphylococcal enterotoxins (SE) are members of a family of more than 20 different exotoxins mostly produced by Staphylococcus aureus and which can cause severe gastroenteritis or even death by ingestion of contaminated food or water samples. Currently, the detection of toxins relies on very complex and time-consuming immunological tests that are typically associated with cross-reactivity, low sensitivity and interference with food matrixes.
Our project intends to select new aptamers that bind to SEs with high affinity and selectivity. Aptamers are typically single-stranded nucleic acid oligonucleotides (ssDNA or RNA) with a complex and specific three-dimensional shape essential for target binding. They provide advantages over antibodies, including robustness, low cost, and no need for animals or cell cultures to be produced binding. Aptamers are selected by the so-called Systematic Evolution of Ligands by Exponential Enrichment (SELEX) process.
The success of selection and the affinity of the resulting aptamers depends on the nature of an initial random nucleic acid library, typically limited to the natural nucleic acids, which restricts the number of potential aptamers and makes them susceptible to nuclease degradation. Therefore, we intend to introduce nucleic acid mimics (NAMs) in the construction of the initial oligonucleotide library and post-SELEX modifications in key residues of aptamers already described. The introduction of NAMs will exponentially increase the number of candidate aptamers and/or increase their stability and affinity.