(93u) Development of an Organophosphate Enzymatic Sensor

Many pesticides currently in use today are part of a family known as organophosphate neurotoxins. Because these chemicals are dangerous and their use is becoming increasingly common, a fast and sensitive analytical device must be created for their detection and quantification. We are developing such a system. In our approach we are taking advantage of competitive enzyme inhibition, and fluorescence modification to measure the amount of neurotoxin. We first attached a gold nanoparticle to the enzyme, and let the labeled enzyme come to equilibrium with a fluorescent decoy. When bound to the enzyme the fluorescent signal of the decoy is modified by the gold. The substrate is then allowed interact with the enzyme and it pushes the fluorescent decoy away from the gold labeled enzyme. Without the interaction of the gold nanoparticle, the fluorescent decoy will return to its normal fluorescent signal. By measuring the change in the signal strength, we can gather information about the neurotoxin. To date we have established the feasibility of developing the sensor, and shown that we can detect certain organophosphates at the nanomolar level. We are in the process of determining optimal reagent concentrations and optical system configuration for classification and quantification of organophosphates.