When it comes to precision agriculture, scientists at the Singapore-MIT Alliance for Research and Technology (SMART) have scored a big technology breakthrough. Benedetto Marelli and his team at Harvard University produced a cutting-edge variety of silk microneedles. These hollow HMNs specifically aim towards the direct delivery of essential nutrients and chemicals to plants. This new paradigm holds great potential to maximize agricultural production and improve public health and environmental outcomes.
The research team, including Yunteng Cao, Ph.D. ’22, and Doyoon Kim, spearheaded the study in collaboration with the Disruptive and Sustainable Technologies for Agricultural Precision (DiSTAP) group. Their efforts address some of the most important questions in US agriculture today. Often, they zero in on the ineffectiveness of conventional pesticide application techniques and methods of delivering nutrients.
Marelli is quick to note that these microneedles represent an exciting opportunity to make agricultural practices more targeted and sustainable. He mentioned that the microneedles are particularly well-suited for treating conditions such as chlorosis by injecting iron directly into an individual plant. Or they can improve the nutritional value of crops, like producing genetically modified tomato plants that contain vitamin B12.
The Development of Microneedles
To prototype these microneedles, fabrication techniques were developed using polyfluoroalkoxy (PFA) materials. Marelli notes that this wasn’t the initial intention behind microneedles, which were first developed for vaccine or drug delivery in humans.
“Microneedles were originally developed for the delivery of vaccines or other drugs in humans,” – Benedetto Marelli
He explained how this technology can be repurposed for agriculture. He emphasized that past efforts to provide the right doses of agrochemicals and nutrients didn’t work.
“Now we’ve adapted it so that the technology can work with plants, but initially we could not deliver sufficient doses of agrochemicals and nutrients to mitigate stressors or enhance crop nutritional values,” – Benedetto Marelli
This ease of the construction process is another striking benefit. Doyoon Kim argued that it doesn’t need high-tech facilities or clean rooms.
“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,” – Doyoon Kim
This universal accessibility makes it possible for farmers and researchers to adopt this technology without investing in expensive infrastructure.
Addressing Agricultural Challenges
Agricultural spraying has resulted in tremendous waste, as less than 5% of sprayed pesticides ever reach the target pests. Marelli noted that 30 to 50% of the pesticides we use typically end up airborne or running off into the ground. This results in them not getting to the crops as needed. This significant inefficiency is a major argument for a greater precision focus.
“There’s a big need to make agriculture more efficient,” – Benedetto Marelli
The microneedles answer the need by enabling direct injection into plant stalks. In their lab-grown experiments, scientists paid special attention to cadmium levels in tomatoes. They discovered that the microneedles had absorbed toxins within 15 minutes of injection. This function demonstrates the possibilities of non-invasive, real-time observation and proactive remediation of crop health.
Marelli imagines a day when autonomous passenger vehicles and agricultural machinery carry out work autonomously. That would set the stage for widespread rollout of this groundbreaking technology.
A Vision for Sustainable Agriculture
Marelli’s long-term vision is for the agricultural practice to exist without negatively impacting environmental health. As the first Chief Agricultural Negotiator, he made clear that, in his opinion, there should not be a trade-off between American agricultural success and ecological sustainability.
“We want to maximize the growth of plants without negatively affecting the health of the farm or the biodiversity of surrounding ecosystems,” – Benedetto Marelli
He highlighted that geo-chemicals are essential for sustaining infrastructures. They must be delivered with precision—not too early, not too late—to save money and avoid harmful environmental effects.
“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,” – Benedetto Marelli
The applications of this research go further than producing healthier crops. Marelli envisions these microneedles as useful tools for plant scientists exploring plant health, like anti-aging and where to grow plants best.
“These microneedles could be a tool for plant scientists so they can understand more about plant health and how they grow,” – Benedetto Marelli
