A growing toolkit from a team at Purdue University now includes a portable, paper-based biosensor designed to identify genetically modified (GM) corn and soybean. Built on a technique known as loop-mediated isothermal amplification (LAMP), this biosensor offers a faster, more affordable alternative to current field-ready molecular diagnostic tools.
Purdue research scientist Bilal Ahmed examines a microfluidic paper-based biosensor cartridge under light to display the visible results of an assay for genetically modified crop traits. Image Credit: Purdue University
Farmers can use it whenever they need it.
Bilal Ahmed, Postdoctoral Research Associate, Agricultural and Biological Engineering, Purdue University
Verma, an associate professor in the department, and his team have previously developed rapid assays for detecting a range of threats, including highly pathogenic avian influenza, fecal contamination on produce, bovine respiratory disease, and COVID-19.
The biosensor technology has been disclosed to the Purdue Innovates Office of Technology Commercialization, which has filed for a patent. Purdue has exclusively licensed the innovation to Krishi, Inc., a company focused on rapid and user-friendly molecular diagnostics. Verma serves as Krishi’s chief technology officer.
This study was the first demonstration from our lab on the use of the biosensors on plant material. It further demonstrates the use of this LAMP-based technology for One Health applications that cut across ecosystems – human, animal, and plant well-being. In addition, we can simplify the use of the biosensors even further through productization as we have demonstrated with Krishi’s SherpaTM Vision platform, which uses a solid-state heater instead of a water bath for improved user-friendliness.
Mohit Verma, Associate Professor, Agricultural and Biological Engineering, Purdue University
Ahmed previously collaborated with Verma to develop the biosensor platform for detecting fecal bacteria on farms. That work, along with their COVID-19 diagnostics research, laid the foundation for the current device targeting genetically modified crop traits.
The biosensor produces results in under an hour after sample extraction and delivers each test for just $2.90—significantly less than other LAMP-based tools, which can run $8 to $9 per test. Hardware costs for Purdue’s system are also lower.
Using only a small, quarter-inch pinch of leaf tissue, the biosensor detects GM traits without requiring DNA purification. In contrast, traditional polymerase chain reaction (PCR) methods need costly lab equipment and highly purified DNA.
“PCR is considered the gold standard in molecular biology,” Ahmed said. “But with this LAMP method, we eliminate the need for DNA extraction and purification.”
Like PCR, LAMP accurately targets specific DNA sequences. “We first optimized our LAMP biosensor method with purified DNA, and then we moved to the crude leaf extract,” Ahmed said.
In the lab, the paper-based biosensor performed well with purified DNA. However, the cost and lab access needed for DNA purification would limit its practicality in the field. That led the team to switch to crude leaf extract.
To prepare the extract, leaf tissue is homogenized, then diluted at a ratio of one part extract to seven parts water.
“We use that crude extract directly with our biosensor. Our biosensor with the leaf extract is as good as purified DNA,” noted Ahmed.
While lateral flow devices also exist for GM crop detection, they rely on protein expression in plants and often fail with hybrids that don’t express the targeted proteins. That’s where this new DNA-focused method offers a clear advantage.
The team designed their biosensor to detect Roundup Ready 1 and 2 soybean varieties, as well as the Roundup Hybridization System 1 (RHS1) trait in corn. Traditionally, farmers remove male tassels from corn plants to prevent self-pollination. RHS1 introduces a trait that achieves the same result chemically.
Ahmed noted, “The male part of the plant specifically is not glyphosate-resistant. Glyphosate is a pesticide. If there is a spray over that plant, the male part will die, but the rest of the plant will survive. We successfully developed our paper-based biosensor based on that particular trait.”
The Purdue-Bayer Crop Science team discussed further possible applications.
Looking ahead, the Purdue-Bayer Crop Science team sees broader potential for the platform. In their journal article, they note that the biosensor, “is adaptable to other GM crops or traits, offering a practical solution for field-level GMO monitoring.”
Journal Reference:
Ahmed, B., et al. (2025) Development of a portable paper-based biosensor for the identification of genetically modified corn (Zea mays) and soybean (Glycine max). Biosensors and Bioelectronics. doi.org/10.1016/j.bios.2025.117690.