By MATEUSZ PERKOWSKI

Capital Press

Tiny, highly specialized tools known as nanoparticles have the potential to transform agriculture and make current "precision ag" devices look like blunt implements in comparison.

Nanotechnology in farming is in its infancy but researchers envision a multitude of uses for nanoparticles -- structures so diminutive they can affect the function of living organisms much more precisely than current agricultural chemistry.

As with pesticides and genetic engineering, however, the prospect of nanotechnology pervading agriculture also makes it a fertile subject for controversy.

Consumers may be reluctant to ingest novel particles with a relatively short history of scientific analysis, while critics worry that existing regulatory structures are inadequate to oversee the new technology.

"This is a world of potentially very exciting opportunities, but anytime you talk about food, there's a lot of potential negative," said Norman Scott, a professor studying agricultural nanotechnology at Cornell University. "The public perception tends to drive some of the hesitancy in the corporate world in this field."

Science fiction

Some of the possible farm applications of nanotechnology may seem like science fiction.

For example, nanoparticles could enable fertilizers to be more biologically available and effective, with the substance also clinging to roots to enhance retention and minimize runoff.

Crops could also be sprayed or dusted with nanoparticles that are highly sensitive to moisture levels within the plants, relaying vastly more accurate information about irrigation requirements than current soil sensors.

"This would be a more direct indication of the plant's status than soil moisture would," Scott said.

Nanoparticles in pesticides could allow the active ingredient to be spread more uniformly across the surface of leaves and stalks, providing better protection with less of the chemical.

Nanotechnology may prove instrumental for food safety, with nanoparticle sensors detecting contamination from microorganisms on crops or in irrigation water.

"You can dip a probe into the water in question and you'll be able to tell," said Hongda Chen, national program leader for nanotechnology at the USDA's National Institute for Food and Agriculture, noting that similar technology could also be embedded in food-packaging material.

Food pathogens could be identified much more rapidly -- for example, by waving a wand-like device over the crop rather than sending samples away for tests, Scott said.

Animal agriculture would likely be impacted as well.

In poultry, for example, plastic nanoparticles in feed could kill dangerous bacteria like campylobacter, which would then by excreted by the chicken before slaughter, Chen said.

How it works

Size is the key factor behind the ability of nanoparticles to behave in useful and unusual ways. The particles are formed of common chemical elements that manifest novel characteristics when manipulated on a very small scale.

The propensity of nanoparticles to perform seemingly complex functions isn't the result of intelligence, said Stacey Harper, an environmental and molecular toxicology professor studying nanotechnology at Oregon State University.

"They're not little nanobots," she said.

Rather, the structure of the particle allows it to fulfill complicated functions.

Scientists use chemical and electrical processes to build up or break down chemical elements to create nanoparticles, Harper said.

By stopping the process at the right time, they're able to form particles composed of specific numbers of atoms, she said. Further processes can "decorate" the particles with additional chemical attributes.

For example, nanoparticles could be engineered to bind with receptors associated with cancer cells as they pass through the body, allowing for diagnosis of the disease, Harper said. A more complex nanoparticle could also release a therapeutic agent to kill those particular cells.

In agriculture, the nanoparticles could be designed to bind with plant cells and detect when a necessary element like nitrogen is in short supply, then release the fertilizer precisely when it's needed.

"It can get into places normal chemicals can't," she said.

That power can be harnessed to help beneficial life forms, like plants, but it can also be turned against destructive ones, like pests.

"A nanoparticle carrier can blast through to the organism," penetrating an insect's natural bodily defenses to deliver a fatal dose of pesticide, Harper said.

That mechanism could be modified to prevent injury to beneficial insects, like bees, she said. "We can be sure to avoid that structure or chemistry as we make up the materials."

Nanoparticles' ability to infiltrate organisms has also resulted in anxiety about the technology's effects on humans, wildlife and the environment.

"They're small so they get through cell walls," Scott said. "The question is, what do they do once they get in?"

Safety concerns

Steve Suppan, senior policy analyst at the Institute for Agriculture and Trade Policy nonprofit, said he's concerned that some nanoparticles, like nanoparticles of silver, may not be immediately toxic when eaten, but would nonetheless have cumulative effects over time.

"It's going to bioaccumulate in the body," he said. "If you're consuming a lot of a crop, how is that going to affect your health?"

The nonprofit group has joined in a lawsuit against the U.S. Food and Drug Administration alleging the agency unlawfully ignored a petition that calls for regulating nanotechnology.

Suppan said he's more satisfied with the U.S. Environmental Protection Agency, which has called on pesticide manufacturers to submit research about nanoparticles to the agency.

Even so, he's worried pesticide companies will forestall such efforts.

"It's just guidance, not a mandatory rule, yet there has been tremendous industry opposition," Suppan said.

The EPA recently released an internal report that confirms some of the concerns about regulatory oversight of nanotechnology.

The agency's Office of Inspector General found that it "does not have sufficient information or processes to effectively manage the human health and environmental risks of nanomaterials."

Covering crops in nanoparticles to prevent damage or spoilage is troubling due to the tiny structures' tendency to migrate, he said. That dynamic could affect the human brain and gastrointestinal systems, since nanoparticles wouldn't be washed off like other chemicals.

"The nanocoating of produce to me is absolutely crazy," Suppan said. "If it's going to go into the flesh, it's going to be consumed."

Scientists don't yet have a clear idea of how to measure the toxicity of nanoparticles, let alone how these novel materials interact with each other, he said. "You don't know what they do individually or what they do in combination."

The Center for Food Safety, another nonprofit group that joined in the lawsuit against the FDA, has similar suspicions about nanotechnology as it does about genetic engineering.

Though nanoparticles could be used for legitimate public good, corporations could use patents to prevent the spread of beneficial technology, said George Kimbrell, an attorney for the group.

"It's like the periodic table is patented," he said.

As nanoparticles are increasingly used in agriculture and other industries, regulatory agencies will face a similar situation as with other new technologies -- balancing the need to protect the public while not blocking scientific progress.

Skip Rung, executive director of the Oregon Nanoscience and Microtechnologies Institute, said it's impossible to eliminate all hazards.

However, people shouldn't avoid nanotechnology any more than they would abandon household chemicals, gasoline or other potentially dangerous substances, he said.

"It's not realistic that everything can be tested and proven safe before it can be used at all," Rung said.