FRET Based Biosensors for CBRN Threat Detection

Advanced sensor capabilities for the simultaneous on-site detection of chemical, biological, and radiological/nuclear (CBRN) threats would significantly limit the risk of exposure to personnel and allow for the rapid, in field collection of essential scientific data. One way to accomplish this is to create a multiplexed Förster Resonance Energy Transfer (FRET) based sensor that is capable of simultaneous CBRN detection. FRET based sensors are tailorable, specific, and highly dependent on donor-acceptor distance, where the distance dependence is the key component of FRET based biosensors. The energy transfer was measured between donors (quantum dot and dyes) and acceptors (gold nanoparticles and quenchers) bound by double-stranded DNA aptamers that target specific CBRN threats. Binding of the target analyte to the DNA aptamer causes conformational changes to the DNA structure that alters the donor-acceptor distance, creating a detectable signal change in the fluorescence response. Nanometal surface energy transfer (NSET) for different plasmonic metal (gold, silver, and copper) nanoparticles was investigated to examine the effectiveness and reliability of these different metals for NSET based biosensing.  Refinements to the original NSET equations with regards to particle size and composition were implemented to measure the effect of energy transfer from different metallic nanoparticles. Calculated NSET and FRET distances for Cu, Ag, and Au metal nanoparticles will be presented as well as results for the detection of a sarin metabolite (methylphosphonic acid) and anthrax protective antigen 63 using different biosensor arrangements.

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