Multiple recombinase polymerase amplification and low-cost array technology for the screening of genetically modified organisms

The identification of different transgenic products that are potentially present in foods is a priority given their impact on environmental safeness and health care. In this context, reliable, fast and inexpensive detection methods are demanded to screen the compliance of product labelling and traceability regulations. We herein developed a method that combines recombinase polymerase amplification (RPA) in a multiple format and a hybridisation assay. This system was optimised for the simultaneous amplification/detection of the 35S promoter, the NOS terminator and taxa, soya (Glycine max), corn (Zea mays) and potato (Solanum tuberosum), to denote the transgenic ingredients present in samples and to help to identify their source. As proof-of-concept, compact disc technology automated the optical sensing of RPA products. Discs worked as an analytical platform in the microarray format, and the reader/recorder as a detector. The analysis of the food mixtures containing genetically modified organisms up to 0.2 % showed excellent selectivity (no false-positives), reproducibility (relative error <20 %) and sensitivity (0.04 ng). The isothermal method was validated using certified reference materials and successfully compared to PCR-ELISA. The results of food products also confirmed it as an effective high-throughput tool for supporting simple, low-cost food safety controls, which makes it ideal for laboratories with limited resources.

Automated summary

The development of a method combining RPA and hybridization analysis allows for rapid and accurate detection of transgenic ingredients in food, supporting compliance with product labeling and traceability regulations. The optical sensing of RPA products using compact disc technology showed excellent selectivity, reproducibility, and sensitivity. This isothermal method provides an effective high-throughput tool for simple and low-cost food safety controls, ideal for laboratories with limited resources.