Dimeric carbocyanine dye and nucleic acid aptamer mediated detection of food borne toxin

Food borne toxins represent a serious challenge to the advances in the operation of the food industry with respect to food processing and distribution. While selective identification of the toxins can be easily accomplished using standard chromatographic and mass spectrometric methods, these are not conducive for use in the field. In this work, we use nucleic acid aptamers in a label-free strategy for detection of specific food borne toxins. Our approach relies on the non-covalent association of a dimeric carbocyanine dye with the quadruplex secondary structures formed by aptamers specific for certain toxins. The presence of a specific toxin Bisphenol A in solution leads to displacement of the dye that manifests as a loss of fluorescence. The work presented here represents an interesting application of the de-aggregation induced fluorescence enhancement of dimeric carbocyanine dyes. Sub-micromolar levels of Bisphenol A can be detected using the aptamerdimeric carbocyanine dye mediated approach. Further, the strategy is specific towards the detection of toxins based on the nucleic acid aptamers used in the assay.