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Under a recent US Office of Naval Research University Affiliated Research Center (UARC) Basic Research Program we have begun a number of activities that we hope will enhance future ability to detect the presence of explosives vapors and residues. Here we present initial work on the development of a microfluidic system for a new point chemical sensor allowing the rapid, accurate, and specific detection of vapors emitted by explosive materials. We have already extensively tested a micromachined platform with external optical excitation and detection. Our new chemical approach is to create a receptor with high affinity and selectivity to nitro-explosives. A series of chemiluminescent molecular signaling systems are proposed that are specifically directed toward detection of TNT, PETN, RDX, HMX, and CL-20. These will be used in a new micromachined platform that integrates photodetectors directly into a micromachined micro-fluidic bead platform for detection of the chemiluminescent signals. By integrating photodetectors into the sidewalls of our chemical sensor array, in immediate proximity to the sensing microbeads, we can eliminate all external optics currently required for optical signal collection. This should allow a more compact and robust system to be constructed by integrating photodetection and fluidics into a single chip-based platform. Additionally, a concept of accessing a photodiode using inductive coupling, i.e. non-contact wireless reading, is introduced and demonstrated.
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