(09/19/19) BATON ROUGE, La. — Nanoparticles made from the corn protein zein may provide the next generation of carriers for agricultural pesticides.
A research team led by scientists in the LSU AgCenter has been awarded a four-year grant of $489,000 from the U.S. Department of Agriculture National Institute of Food and Agriculture to study the environmental fate and effects of engineered nanoparticles — particles that are 1,000 times smaller than the width of a human hair — developed to deliver agricultural chemicals.
The study, led by AgCenter researcher Cristina Sabliov in the Department of Biological and Agricultural Engineering, focuses on the interactions between the zein nanoparticles, called ZNPs, and the environment, including plants and insects.
As pesticide carriers, the particles entrap the chemicals and provide more-targeted application with less runoff or improper exposure. The ZNPs are biodegradable.
“We want to know their impacts on plants and insects,” Sabliov said. “We’re taking an integrated approach to see what happens with the ZNPs in the environment.”
Most pesticides are not water soluble, so they must be formulated with surfactants or solvents before spraying on a plant’s surface. The ZNPs, on the other hand, are water soluble and can be used as carriers for the pesticides.
The project will assess the ZNPs as a chemical delivery system and evaluate how they adhere to a plant’s leaves and roots and move through them.
To get the material to adhere to a plant, the ZNPs must carry a positive electrical charge because the leaf surface has a negative charge. Surface properties of nanoparticles make a difference on how they move in the environment, degrade and affect the entrapped pesticide.
To test the environmental effects of the ZNPs, Sabliov and researcher Carlos Astete are developing nanoparticles with three electrical charges — positive, negative and neutral. To assure the environmental safety of the ZNPs, Sabliov’s team includes two scientists who will evaluate the environmental effects of the particles that have a positive, negative or neutral charge.
Melanie Kah at the University of Auckland in New Zealand will evaluate the environmental fate of the particles, including their persistence in nature. Jason White, chief analytical chemist at the Connecticut Agricultural Experiment Station, will test how the particles affect plant health.
In both cases, the particles will be “empty,” containing no pesticides.
“This will ensure the effects of the carrier itself are measured, and the hope is that the particles will not be harmful to plants or the environment,” Sabliov said. “They will be field tested and not be restricted to a laboratory.”
The scientists know the ZNPs will degrade. The question they want to answer is how long it will take and what will happen in the meantime. “Because the materials are biodegradable, we know they are safe by design,” Sabliov said.
In addition to environmental activity, AgCenter entomologist Jeff Davis will test ZNPs with an entrapped insecticide to determine their effectiveness as a pesticide carrier for treating for soybean loopers, an important soybean defoliator; fall armyworms; and corn earworms.
”We want to use ZNPs to improve the efficiency of pesticides without impacting the environment,” Sabliov said. Early indications are that the pesticide has longer efficacy in the plant when it’s applied in ZNPs.
Sabliov began her work with nanoparticles and pharmaceuticals and moved on to expand her research to improve the environmental safety of agricultural chemicals.
Sabliov’s early work with ZNPs and soybean looper pesticides was funded with grants from the Louisiana Soybean and Grain Promotion Board. She also has had support from the Louisiana Farm Bureau.
LSU AgCenter graduate assistant Colin Bonser, second from right, shows a container of zein nanoparticles with an entrapped insecticide and soybean loopers to AgCenter researchers, from left, Cristina Sabliov, Jeff Davis and Carlos Astete. Photo by Rick Bogren/LSU AgCenter
A soybean looper is placed in a container of zein nanoparticles with an entrapped insecticide to determine their effectiveness as a pesticide carrier for treating the looper, an important soybean defoliator. Photo by Rick Bogren/LSU AgCenter