Tag Archives: Food and Agriculture Organization (FAO)

Nanoparticle smart spray for crop protection

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Caption: Image at 3,000x magnification shows the SENDS nanoparticles (in blue) surrounding the stomata of a plant Credit: College of Design and Engineering at NUS

A June 2, 2025 National University of Singapore College of Design and Engineering press release (also on EurekAlert) announces a nanoparticle smart spray, Note: A link has been removed,

As climate change fuels the spread of plant diseases worldwide, a new nanoparticle smart spray could help crops defend themselves by blocking harmful bacteria from entering through tiny pores in their leaves.

The spray is made of nano-sized particles developed by a team led by Assistant Professor Tedrick Lew from the Department of Chemical and Biomolecular Engineering in the College of Design and Engineering at the National University of Singapore (NUS). These nanoparticles are designed to deliver antibacterial compounds directly to the plant’s stomata – the pores on a plant’s leaves that let it breathe, but which can also act as gateways for infection.

“The particles, which we’ve called ‘SENDS’ – short for stomata-targeting engineered nanoparticles – are designed to stick precisely to these pores, like a lock finding its key,” said Asst Prof Lew. “Once in place, they release natural antibacterial agents that stop pathogens from getting inside and infecting the plant.”

The team’s research was published in the journal Nature Communications on 23 May 2025.

Smarter tools

According to the United Nations Food and Agriculture Organisation, plant diseases destroy an estimated US$220 billion worth of crops globally every year. 

Rising temperatures and shifting weather patterns caused by climate change are giving pests and pathogens more opportunities to spread. Left unchecked, these could erase many of the gains expected from new farming technologies and improved crop varieties.

“Around the world, climate change is making it easier for plant diseases to spread and harder for farmers to keep them under control,” said Asst Prof Lew. “We need smarter tools that help plants protect themselves in a more precise and sustainable way.”

Unlike conventional pesticides that blanket entire plants and can harm surrounding ecosystems, SENDS delivers treatment precisely where it is needed, minimising waste and collateral damage.

The particles are made from zinc, a micronutrient already found in fertilisers. They are engineered to be porous so they can carry antibacterial agents, and they gradually dissolve after being sprayed, releasing their contents over time. The result is a water-based spray that can be applied just like conventional agricultural treatments and which leaves the plants’ natural functions, such as photosynthesis and gas exchange, unaffected.

20 times more resistant

In lab tests, the research team showed that plants treated with the targeted particles were 20 times more resistant to infection than those given non-targeted treatments. The spray worked on a range of food crops, including leafy vegetables such as pak choy, beans, rice and barley. It also stuck well to leaf surfaces even after rainfall, helping reduce runoff and pollution from excess agrochemicals.

“This is about stopping infections before they start,” said Asst Prof Lew. “By blocking bacteria entry precisely at the gate, we protect the plant without overwhelming it with chemicals.”

The researchers believe the same approach could be adapted for a wide range of crops and used to deliver other treatments, such as pesticides or RNA-based molecules. It should also be suitable for use in most farming regions around the world, they say.

Whilst further development and field tests are needed, the SENDS technology could help reduce farmers’ reliance on excessive chemical sprays while improving crop resilience, helping to boost food security and protect the environment.

Here’s a link to and a citation for the paper,

Stomata-targeted nanocarriers enhance plant defense against pathogen colonization by Suppanat Puangpathumanond, Heng Li Chee, Cansu Sevencan, Xin Yang, On Sun Lau & Tedrick Thomas Salim Lew. Nature Communications volume 16, Article number: 4816 (2025) DOI: https://doi.org/10.1038/s41467-025-60112-w Published: 23 May 2025

This paper is behind a paywall.

Coat fruit with silk to keep it fresh

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A May 6, 2016 news item on ScienceDaily describes a way to keep fruit fresh without refrigeration,

Half of the world’s fruit and vegetable crops are lost during the food supply chain, due mostly to premature deterioration of these perishable foods, according to the Food and Agriculture Organization (FAO) of the United Nations.

Tufts University biomedical engineers have demonstrated that fruits can stay fresh for more than a week without refrigeration if they are coated in an odorless, biocompatible silk solution so thin as to be virtually invisible. The approach is a promising alternative for preservation of delicate foods using a naturally derived material and a water-based manufacturing process.

A May 6, 2016 Tufts University news release (also on EurekAlert), which originated the news item, describes the work,

Silk’s unique crystalline structure makes it one of nature’s toughest materials. Fibroin, an insoluble protein found in silk, has a remarkable ability to stabilize and protect other materials while being fully biocompatible and biodegradable.

For the study, researchers dipped freshly picked strawberries in a solution of 1 percent silk fibroin protein; the coating process was repeated up to four times.  The silk fibroin-coated fruits were then treated for varying amounts of time with water vapor under vacuum (water annealed) to create varying percentages of crystalline beta-sheets in the coating. The longer the exposure, the higher the percentage of beta-sheets and the more robust the fibroin coating. The coating was 27 to 35 microns thick.

The strawberries were then stored at room temperature. Uncoated berries were compared over time with berries dipped in varying numbers of coats of silk that had been annealed for different periods of time. At seven days, the berries coated with the higher beta-sheet silk were still juicy and firm while the uncoated berries were dehydrated and discolored.

Tests showed that the silk coating prolonged the freshness of the fruits by slowing fruit respiration, extending fruit firmness and preventing decay.

“The beta-sheet content of the edible silk fibroin coatings made the strawberries less permeable to carbon dioxide and oxygen. We saw a statistically significant delay in the decay of the fruit,” said senior and corresponding study author Fiorenzo G. Omenetto, Ph.D. Omenetto is the Frank C. Doble Professor in the Department of Biomedical Engineering and also has appointments in the Department of Electrical Engineering and in the Department of Physics in the School of Arts and Sciences.

Similar experiments were performed on bananas, which, unlike strawberries, are able to ripen after they are harvested. The silk coating decreased the bananas’ ripening rate compared with uncoated controls and added firmness to the fruit by preventing softening of the peel.

The thin, odorless silk coating did not affect fruit texture.  Taste was not studied.

“Various therapeutic agents could be easily added to the water-based silk solution used for the coatings, so we could potentially both preserve and add therapeutic function to consumable goods without the need for complex chemistries,” said the study’s first author, Benedetto Marelli, Ph.D., formerly a post-doctoral associate in the Omenetto laboratory and now at MIT.

Here’s a link to and a citation for the paper,

Silk Fibroin as Edible Coating for Perishable Food Preservation by B. Marelli, M. A. Brenckle, D. L. Kaplan & F. G. Omenetto. Scientific Reports 6, Article number: 25263 (2016) doi:10.1038/srep25263 Published online: 06 May 2016

This is an open access paper.