doi:10.1038/nindia.2011.82 Published online 20 June 2011
Researchers have devised a new low-cost disposable sensor that could be used to detect diuron, a pesticide with the potential to cause cancer.
Diuron is a phenyl urea herbicide used to control weeds across a wide variety of crops. The prolonged use of diuron and other phenyl urea herbicides is a concern because residues of these chemicals remain in surface and ground water for long periods of time. Diuron has been found to adversely affect plants, animals and humans by disrupting hormonal balance.
To design a low-cost technique for detecting diuron, the researchers first produced gold electrodes by smearing gold particles on a polyester substrate. After modifying the gold electrode with laser light, they electrochemically deposited a thin film of the pigment prussian blue embedded with gold nanoparticles. They then coated the resulting film with anti-diuron antibodies to yield the low-cost disposable sensor.
The sensor exhibited excellent sensitivity and specificity, with a dynamic response range of between 1 part per trillion and 10 parts per million. The sensor also demonstrated good response over repeat experiments. The high sensitivity of the sensor is due to the large surface activity of gold nanoparticles embedded in the prussian blue film, which increases the efficiency of electron delocalization.
"This study provides a method for rapidly screening environmental samples for pesticides at very low cost," says lead researcher C. Raman Suri. The work is particularly significant now that the US Environmental Protection Agency has classified diuron as a likely carcinogen, he concludes.
- Sharma, P. et al. A novel disposable electrochemical immunosensor for phenyl urea herbicide diuron. Biosens. Bioelectron. 26, 4209-4212 (2011)