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The perchlorate generated over decades has impacted our nation's waters; it is environmentally recalcitrant and potentially toxic. Perchlorate has emerged as a significant threat to public health. Recent detection of perchlorate in human breast milk is a major public health threat. Substantial efforts are dedicated to perchlorate removal and its determination down to the lowest possible limit of detection (LoD). The Enviromental Protection Agency (EPA) has set 3.6 ìg/L (ppb) as a preliminary LoD objective. There is a strong need and opportunity to develop simple and inexpensive analytical methods with lowest possible LoD, overcoming any interference.
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This project will develop an inexpensive, highly sensitive, highly selective, and fast-responding biosensor for detecting perchlorate down to 1 ppb using an enzyme immobilized on conducting polymer nanoarrays.
NON-TECHNICAL SUMMARY: The proposed project focuses on development of an inexpensive and field-ready device for rapid detection of perchlorate in water and soil with high sensitivity and selectivity at low LoD. Phase I will result in a field-ready perchlorate nanobiosensor, with 1 ppb LoD. This device will dramatically lower the time and cost of perchlorate analysis. The proposed biosensor will be suitable for field use, laboratory analysis and on line monitoring, which facilitates cost-effective and convenient monitoring of perchlorate in groundwater, soil, drinking-water, food and beverages. In addition, the biosensor will be useable by breast feeding mothers for milk evaluation at home. It will thus contribute towards improvement of public health. In addition, the conducting polymer NW and NT arrays proposed in this project would have many applications beyond a perchlorate biosensor; the conducting polymer nano-arrays to be developed and investigated in the proposed project would serve as a protocol for other biosensor applications.
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APPROACH: The proposed perchlorate biosensor platform is based on immobilization of perchlorate-sensitive enzymes, either by electrodeposition or self assembly, on conducting polymer nanowire (NW) or nanotubule (NT) arrays. Most significantly, this enzymatic nanoarray provides the highest specific area-to-volume ratio and direct nanoscale electrical transfer with working electrode, via conducting polymer with porous hyper-branched nanostructures. As a result, the electron transfer and biocatalytic reaction are dramatically multiplied, promising to boost sensitivity by an order of magnitude, dramatically improve the response time, and lower the LoD.