doi:10.1038/nindia.2016.98 Published online 28 July 2016
Researchers have synthesized a sensitive biosensor that can detect minute traces of malathion, a pesticide widely used to kill insects that destroy crops and invade homes1.
Malathion contaminates soil and water and is is highly toxic for bees, other beneficial insects and aquatic life. Current techniques for detecting malathion are complex and time-consuming.
The researchers devised a simple sensor for detecting malathion using unmodified gold nanoparticles, single stranded nucleic acid known as aptamer and a water-soluble positively charged electrolyte. They used the biosensor to detect the pesticide in artificial solutions as well as real samples such as apples and lake water.
When exposed to these samples, the aptamer bound to the pesticide, freeing the electrolyte that caused aggregation of the gold nanoparticles. These interactions resulted in changing the colour of the solutions from red to blue.The colour depends on the concentration of the electrolyte, which is directly linked to the concentration of malathion.
The biosensor selectively detected malathion even in the presence of interfering agents such as other pesticides. The researchers say this suggests that the biosensor is highly sensitive and selective for monitoring the concentration of malathion in environmental samples.
1. Bala, R. et al. Ultrasensitive aptamer biosensor for malathion detection based on cationic polymer and gold nanoparticles. Biosens. Bioelectron. 85, 445-449 (2016)