NANOPARTICLE SENSORS FOR PHEROMONES FROM INSECT AGRICULTURAL PESTS

The long-term goal of this project is to develop an inexpensive field-deployable sensor for pest-species-specific insect pheromones. A sensor of this type inverts the current practice of using species-specific pheromones as trap baits to detect the presence of the insect pest. An alternative type of sensor is needed because in field conditions pheromone-baited insect traps cannot determine whether or when trapped males have mated. By contrast, detection of mating pheromones precedes or is coincident with mating activity, thereby more reliably serving as advance warning of pest activity. An example of the economic stakes in the technology of crop pest field detection, the losses from the corn earworm, Helicoverpa zea, are estimated to be $1 billion per year. Control of H. zea with Bt toxin may eventually become ineffective due to the development of resistance. Furthermore, it is believed that the Old World bollworm, Helicoverpa armigera, will most likely soon invade the U.S. from the Caribbean region where it is now established, adding to the economic losses. These huge costs and the possible future ineffectiveness of Bt as a control tool justify work to develop new methods of detection and control. The objectives of this proposal are to test the feasibility of using insect odorant receptors (ORs) as pheromone nanosensors, using two different sensor mechanisms: 1) displacement of a dye from the OR when the pheromone binds, thus eliminating a photoluminescence signal from a quantum dot nanoparticle; and 2) fluorescent dye-based detection of Ca2+ ions that are admitted into a mesoporous silica-coated gold nanoparticle after pheromone molecules trigger the opening of the OR ion channel.