Drug delivery has long been a core field of medical research. Organic and inorganic-based nanoparticles such as liposomes, micelles, and dendrimers have been developed to deliver drugs precisely to specific organs such as cancer cells, and the technology ultimately led to blockbuster anticancer drugs such as Doxil and Abraxane. It was thanks to advantages offered by nanotechnology, including improved drug solubility, organ targeting, and longer circulation time in the body.
But one researcher has applied this technology to plants, taking a new "precision delivery" approach to agriculture. He is Assistant Professor Tedrick Thomas Salim Lew at the National University of Singapore (NUS). His lab spans materials science, chemistry, and plant biology to study how plants sense and respond to stress. The goal is simple: to help plants withstand conditions better in the era of climate change.
Lew met with ChosunBiz on the 5th (local time) in Singapore's Central Area and said, "For decades, the medical field has chemically tuned nanoparticle surfaces to deliver drugs precisely to desired organs such as the lungs, kidneys, and tumors," adding, "But in agriculture, no one asked, 'Why do fertilizers or pesticides still rely on random spraying?'"
◇90% of fertilizer and pesticides are wasted… finding answers at the "stomata"
Lew's line of questioning began in an unexpected place. During his Ph.D. at the Massachusetts Institute of Technology (MIT), he came up with the idea of "applying nanoparticles used in animals to plants." His then-advisor, Michael Strano, had a major influence. Strano is a globally recognized scholar in technologies that deliver nanomaterials into cells.
In fact, less than 10% of the fertilizers and pesticides sprayed in the field remain on plant leaves. The other 90% flows into soil and waterways, causing environmental problems such as algal blooms and red tides. The expense waste is also significant.
Lew focused on the tiny pores on the surface of leaves, namely stomata. Unlike previous research that concentrated on "deep delivery" targeting intracellular organelles (nuclei, mitochondria, etc.), he determined that "we should start where the door is."
"Stomata are the mouth through which plants breathe and the entryway through which bacteria invade," Lew said. "If this part is exposed while open, pathogens can enter as is."
He chemically engineered the nanoparticle surface to bind to specific sugars on the surface of stomata. This is the so-called SENDS (surface ligand-engineered nanoparticles for targeted delivery to stomata) technology. Antimicrobial nanoparticles "cling" to stomata to block bacterial invasion while also improving the absorption efficiency of fertilizers and pesticides.
The effects were clear. Absorption and delivery efficiency up to 20 times higher than conventional spraying methods was confirmed. "Nanoparticles wait attached to stomata like a kind of guard," Lew said. "When harmful bacteria attempt to enter, they are suppressed on the spot."
The technology is still at the laboratory stage, but industry interest is substantial. Singapore is a city-state that imports 90% of its food and aims to achieve a 30% food self-sufficiency rate by 2030. That is why Lew's technology is drawing attention as a new tool to enhance the productivity and stability of urban agriculture.
"The results are very encouraging, but to verify the same performance on actual farms, larger-scale trials are needed," Lew said. "We are currently discussing field validation partnerships with Singapore corporations." Once the paperwork is finalized, full-scale work is set to begin next year.
◇"Building trust is harder than the technology"… high expense also a challenge
But there are hurdles to applying nanotechnology to agriculture. "When people hear the word 'nanotechnology,' they worry first," Lew said. That is because of the misconception that it is "bad for the body."
"That is why we are developing more environmentally friendly nanoparticles that can degrade in nature," Lew explained, adding, "They are not very different from the nanoparticles in proteins we eat or those that exist naturally in the air." He said, "Humans are already exposed to countless nanoparticles in toothpaste and various consumer goods," and added, "For large-scale adoption, we need to clearly demonstrate that they are safe for use in food."
Public perception also affects regulation. "Regulation ultimately starts from public perception," Lew said. "We need to persuade the public and policymakers that nanoparticles are already widespread around us." He emphasized, "People voluntarily inject nanoparticles in vaccines such as those for COVID-19. Applying the same nanoparticles to plants and then eating that food does not cause genetic modification or health problems."
Expense is also an issue. "The reason our research scope is currently limited is that the chemical approach uses proteins," Lew said. "Proteins are expensive." "The reason stomatal targeting is possible is thanks to antibody-based technology, and antibodies are also proteins," he said.
"People accept high-priced technologies used in medicine, but they are reluctant to spend that much expense on cheap crops like vegetables," Lew said. "We have already scientifically demonstrated what role stomata can play in plant protection. Going forward, we will focus on developing materials and chemical approaches that can achieve the same effects at much lower cost."
References
Nature Communications (2025), DOI: https://doi.org/10.1038/s41467-025-60112-w