Optical sensor for pesticides
doi:10.1038/nindia.2010.188 Published online 31 December 2010
Researchers have designed an optical biosensor, which can detect organophosphorous pesticides such as methyl parathion, using bacteria .
Organophosphorus pesticides such as methyl parathion have been widely used in the field of agriculture for insect pest control. These pesticides and their products cause environmental pollution. Methyl parathion is readily absorbed through the skin and toxic in inhaled, ingested or dermally adsorbed.
To devise a suitable sensor, the researchers selected a bacterium called Sphingomonas species isolated from field soil. The researchers immobilized the whole cells of the bacteria onto the surface of the wells of polystyrene microplates using an organic compound.
The study found that the bacterium hydrolyzes methyl parathion into a colour-giving product called para-nitrophenol, which can be detected by electrochemical method. The microplate-based biosensor has 96 reaction vessels and therefore provides a convenient system for detecting multiple numbers of samples in a single platform.
Cells-immobilized microplates could be reused up to 75 reactions. The study reports an innovative concept where the microplate can be used as immobilizing support for development of reusable microbial biocomponent.