Development of a portable paper-based biosensor for the identification of genetically modified corn (Zea mays) and soybean (Glycine max)

Genetically modified (GM) crops like corn and soy offer enhanced resistance traits but require consistent monitoring to manage gene flow, prevent resistant pests/weeds, and ensure regulatory compliance. In this study, we present a novel loop-mediated isothermal amplification (LAMP)-based microfluidic paper-based analytical device (μPAD) biosensor for the rapid and cost-effective detection of hybrid corn (Roundup Hybridization System 1, RHS1) and soy (Roundup-Ready 1 and 2, RR1 and RR2) traits directly from crude leaf extracts. Our μPAD-LAMP assay offers a promising solution for GM detection, characterized by its speed (within 60 min), simplicity (straightforward design), and affordability ($2.90 per test). We developed μPAD-LAMP cartridges and utilized an image analysis algorithm for time-resolved quantification of colorimetric changes, improving objectivity and accuracy. Our platform detected GM traits at 65 °C using a 1:7 dilution of leaf extracts in 0.12-0.25 % SDS in water, without needing DNA purification. The limit of detection (LoD) for RHS1, RR1, and RR2 targets was 1.40 × 10³, 1.10 × 10³, and 1.00 × 10³ genomic copies per reaction, respectively, with our μPAD-LAMP system. This portable μPAD-LAMP platform achieves 100 % specificity, sensitivity, and accuracy in detecting GM corn and soy from leaf extracts, demonstrating its potential as a reliable on-site detection tool. Its adaptability to other GM crops or gene targets positions it as a promising standard for point-of-need (PON) assays in the GM industry.