A FRET Approach to Detect Paraoxon among Organophosphate Pesticides Using a Fluorescent Biosensor

Area of Science:

• Biotechnology
• Environmental Science
• Analytical Chemistry

Background:

• Organophosphate (OP) pesticide detection is critical for environmental safety.
• Enzyme-based biosensors offer sensitive and real-time monitoring solutions.
• Esterase-2 (EST2) from Alicyclobacillus acidocaldarius is a promising bioreceptor due to its high affinity for OPs.

Purpose of the Study:

• To evaluate Förster resonance energy transfer (FRET) for sensitive quantification of OPs.
• To assess the applicability of an IAEDANS-labeled EST2-S35C mutant biosensor.
• To determine OP detection limits at environmentally relevant concentrations.

Main Methods:

• Utilized a Förster resonance energy transfer (FRET) system with a tryptophan donor and IAEDANS acceptor.
• Employed a previously developed IAEDANS-labeled EST2-S35C mutant enzyme.
• Performed fluorometric measurements to quantify paraoxon, an OP simulant.

Main Results:

• Demonstrated linear correlation between EST2-S35C concentration and fluorescence.
• Confirmed no significant interference from common environmental components (pH, glucose, yeast extract).
• Achieved sensitive detection of paraoxon down to 2 nM, an ecologically harmful concentration.

Conclusions:

• The FRET-based EST2 biosensor is a sensitive and reliable tool for OP detection.
• This method is suitable for monitoring OPs at environmentally relevant, low concentrations.
• Results support further development for complex environmental matrix analysis.