Fluorescence Based Enzymatic Sensor for Organophosphate Neurotoxins

Organophosphates are strong acetylcholinesterase inhibitors, and are becoming increasingly popular in their application as insecticides and chemical warfare agents. We are trying to develop a new sensing technology that is faster, more robust, and more mobile than current methods. We are taking advantage of principles of surface modified fluorescence and competitive enzyme inhibition to quantify and characterize organophosphates. The system being developed consists of an enzyme that is modified with a gold nanoparticle, an inhibitor of this enzyme that is fluorescent by nature, and the organophosphate to be detected. The gold nanoparticle will alter the fluorescent signal of the inhibitor when the inhibitor is bound to the enzyme. By measuring the rate of and the total changes in the fluorescent signal when an organophosphate is introduced, we can characterize the organophosphate. We have experimentally determined many necessary parameters and protocols associated with the physical system. We have also developed a MATLAB program that compares a model of the sensor system to the fluorescent signal coming from the sensor and reports organophosphate identity, concentration, and the degree of certainty to which these are estimated. This sensor platform could have applications in environmental monitoring of food and water and in homeland security.