Indian researchers working on pesticides that use nanoparticles

Date:01-10-2011

Indian scientists are working on developing the next generation of pesticides that employ nanoparticles, have potentially reduced toxicity, and can dramatically slash costs and in the next few years challenge the 2,000 crore pesticide market in India.

Researchers at the Kolkata-based Indian Statistical Institute (ISI) have developed techniques to modify the molecular structure of silica, a commonly available compound, to use it as a pesticide. Silica is used in a variety of non-agricultural applications and is considered harmless to humans.

To commercialize this technology, the researchers have filed for patents, tied up with a company, and secured funding from the department of biotechnology to improve their process.

Nanoparticles are ordinary elements crushed to a thousandth of the width of a human hair. At those levels, elements show dramatically altered properties—for example, some that conduct electricity become non-conductors—that scientists are now trying to apply to a variety of commercial applications.

Silica, in its nanoscopic avatar and used as a pesticide, can fatally drain key lipids out of a pest.

"When used this way, the volume of pesticide required to kill a pest dramatically reduces, and this can be easily washed away. When there are no residues, toxicological effects cease to be a problem,” said R.R. Sinha, an official at the department of biotechnology coordinating the project.

Scientists associated with the project say three-year-long tests have shown that pesticides in this form were effective in containing pests such as rice weevils and mustard aphids. Rice is among the biggest consumers of pesticides, followed by cotton, on which studies are yet to be done.

The focus of the scientists’ research is to be absolutely sure that nanoparticles are not in any way harmful to humans.

"We have tested particles ranging from 15-60 nanometre in size on several kinds of tissue, including the spleen and liver,” said Arunava Goswami, an associate professor at ISI and the key scientist associated with the project. “However, there are some tests to be done on lung tissue and we also have to study the effects of particles below 15 nanometre to be entirely safe.”

A commercial product, though, is unlikely to hit the market before 2013, primarily because few companies have the facilities to manufacture nanoparticles in quantities above 100kg, said Goswami.

"For commercial purposes, you need to manufacture in tonnes, and such facilities don’t exist yet. Also, just like genetically modified crops, there’s likely to be concerns on the health effects of nanoparticles. That’s why we’re trying to address these issues early on,” said Goswami.

He added that using nanoparticles would sharply reduce the cost of manufacturing pesticides.

"As an example, we need, say, 2,000 units of a pesticide to kill a certain quantity of pests, but with these nanoparticles you need only 125 units to achieve a similar results. That could dramatically cut manufacturing costs,” said Goswami.

Nathan Daniel, a chemical engineer at the University of Delhi, said several international companies were working on nanoparticle-based fertilizers that would significantly change the pesticides market.

"Several patents have been filed internationally... It’s something that will be a major game changer,” he said.

Studies have suggested that nanoparticles could easily lodge themselves within the body and cause respiratory problems, Mint had reported in January 2008.

In 2006, several German firms were forced to withdraw their cleaning products, all of which claimed to use nanoparticles. Many of these products caused respiratory problems.

But a study by the German Federal Institute for Risk Assessment found that while these effects were caused by the products, none of them actually contained nanoparticles.

K. Sridhar, a microbiologist at Mangalore University who has authored a research paper on nanotechnology pollution, said that while some studies have showed that nanoparticles have adverse health effects, most showed they had none.

Source: livemint.com