Biosensors to Monitor Water Quality Utilizing Insect Odorant-Binding Proteins as Detector Elements.

Area of Science:

• Biotechnology and Biosensor Development
• Environmental Science and Public Health

Background:

• Waterborne diseases from fecal contamination pose a significant public health threat, especially in developing regions.
• Current methods for detecting water contamination are often costly, slow, or unreliable, hindering effective local monitoring.
• There is a critical need for accessible, rapid, and accurate tools to assess the safety of drinking water supplies.

Purpose of the Study:

• To develop a novel, low-cost biosensor for the rapid detection of coliform bacteria in water.
• To investigate the utility of insect odorant-binding proteins (OBPs) as sensitive detection elements in biosensors.
• To demonstrate a proof-of-concept for a portable, dipstick-style biosensor for water quality monitoring.

Main Methods:

• Utilized recombinantly expressed AgamOBP1, an odorant-binding protein from the mosquito *Anopheles gambiae*.
• Developed a fluorescence-based in vitro assay to detect indole, a metabolite produced by coliform bacteria.
• Evaluated the binding affinity of AgamOBP1 to indole and its suitability for biosensor applications.

Main Results:

• Recombinant AgamOBP1 demonstrated high sensitivity in binding to indole.
• The developed assay successfully detected the presence of bacterial metabolic markers indicative of coliform contamination.
• AgamOBP1 proved suitable for integration into portable, inexpensive 'dipstick' biosensors, outperforming existing lateral flow technologies.

Conclusions:

• Insect OBPs are effective and robust detector elements for novel biosensors.
• This technology enables rapid, low-cost detection of coliform bacteria by identifying specific metabolic markers.
• The presented platform technology holds potential for diverse biosensor applications beyond water quality monitoring.