In a straightforward shift towards precision in agriculture, researchers at MIT and Singapore have uncovered a novel method to bolster plant health and fortification using silk microneedles. Detailed in a study recently published in Nature Nanotechnology, this technology streamlines the delivery of nutrients and agrochemicals to plants, addressing the hefty losses and environmental impacts generally associated with traditional methods like spraying pesticides.
Traditionally, spraying pesticides on crops has been akin to casting a wide net, with a significant amount -- somewhere between 30 to 50 percent -- missing the target and instead dispersing into the surrounding environment. The researchers from the Marelli lab have, inadvertently revealing a persistent problem, engineered silk-based microneedles that inject substances directly into plant tissues, increasing efficiency and potentially reducing waste and ecological harm. Benedetto Marelli, the study's senior author and an MIT associate professor, explained, "Agrochemicals are important for supporting our food system, but they're also expensive and bring environmental side effects, so there's a big need to deliver them precisely."
The study was spearheaded by two lead researchers, Yunteng Cao, now a postdoc at Yale University, and Doyoon Kim, a former postdoc in Marelli's lab, and included collaboration with DiSTAP, a research group at the Singapore-MIT Alliance for Research and Technology (SMART). In a bold move, these tiny needles have been employed to administer iron to iron-deficient tomato plants and introduce vitamin B12 to tomatoes to augment their nutritional content.
Making use of the silk microneedles, the researchers demonstrated the fortification of crops against diseases like chlorosis and the enhancement of tomatoes with vitamin B12, a nutrient mostly found in animal products. With a candid nod to the potential applications, Marelli said, "These microneedles could be a tool for plant scientists so they can understand more about plant health and how they grow." Demonstrating another innovative use for the microneedles, Marelli's team has explored their capabilities in real-time plant health monitoring, particularly in detecting toxic substances such as cadmium from contaminated soils.
Behind the scenes, this advancement was made possible by a simplified manufacturing process that forgoes the need for clean rooms and expensive equipment. Instead, a salty solution is mixed with silk fibroin protein and shaped inside tiny molds. As water evaporates, silk solidifies around crystalline structures formed by the salt, which, once removed, leaves behind the desired hollow or porous microneedles. As Marelli told MIT News, "It's a pretty simple fabrication process. It can be done outside of a clean room — you could do it in your kitchen if you wanted. It doesn’t require any expensive machinery."
While the application of microneedles has been manual for the scope of the study, Marelli envisions future automation through the integration with existing agricultural machinery. This technique not only promises a more eco-friendly approach to bolstering crop health and yields but also paves the way for potential applications in areas beyond agriculture. The research, receiving backing from entities like the U.S. Office of Naval Research, the National Science Foundation, SMART, the National Research Foundation of Singapore, and the Singapore Prime Minister’s Office, offers a distinct pathway for the convergence of agricultural efficiency and environmental conscientiousness.
