Development of Novel Patulin Aptamer Using GO-SELEX and Detection of Patulin in Apple Juices

Introduction: Patulin (PAT) is one of the mycotoxins produced by some fungi, such as Penicillium, Aspergillus and Byssochlamys. PAT is known as carcinogenic, mutagenic, and teratogenic and mainly found in rotten apples and apple juices. In order to prevent exposure to the PAT, many countries have set regulation limits on PAT. However, due to its simple structures, there is no commercialized bio-receptor against PAT.

Purpose: We developed novel PAT binding aptamers and applied the aptamers to detect the PAT in apple juices by lateral flow assay (LFA) and localized surface plasmonic assay (LSPR).

Methods: Aptamers specific to PAT were developed through a systematic evolution of ligands by exponential enrichment (SELEX) based on graphene-oxide (GO-SELEX) using 30, 40, 50, and 60 mer single strand DNAs (ssDNAs) library. Unbound ssDNAs are absorbed on the GO, but ssDNAs bound with PAT are not. In addition, we used the aptamers to develop a lateral flow assay (LFA) and localized surface plasmonic assay (LSPR) for the detection of the PAT in apple juices.

Results: Eight aptamers (Papta No. 1 -8) specific to PAT were successfully developed by GO-SELEX. Among the 8 aptamers, Papta No. 6 showed the highest affinity to PAT. Thus, we used the aptamer to develop and optimize LFA and LSPR assays. The detection limits of both methods are all 5 µg/ml in buffer and apple juice.

Significance: Recently, since aptamers have been considered as a good candidate to replace antibodies which are used in other immunoassays, the aptamer-based dipstick assay developed in this study is superior to other immunoassays with respect to its setting speed and stability. In this study, we firstly reported PAT binding aptamers and aptamer-assays. The results provide great opportunities to apply the aptamer to the development of aptamer assays for PAT analysis.