AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Fluorophore-Tagged Reagents for Aerosol Experiments
CYNTHIA J. KAESER, Elizabeth K. Wheeler, Joanne J. Osburn, A. Daniel Jones, George R. Farquar, Lawrence Livermore National Laboratory
Abstract Number: 489 Working Group: Homeland Security
Abstract Fluorophore-tagged particles have been developed to expand the suite of human-safe bioaerosol simulants to include simulants for fluorescence biodetector testing. Combining the FDA-approved saccharide food additives used as the bulk material in the R&D100 award-winning DNA-tagged biosimulant DNATrax with naturally fluorescing amino acids and vitamins, the modified tags make this simulant suitable for fluorescent-based biodetector network evaluation and aerosol transport studies while being biodegradable and safe for human exposure.
Many currently available biodetectors take advantage of the natural fluorescence of aromatic amino acids and use a combination of ultraviolet laser induced fluorescence (UVLIF) with light scattering size determination to identify bioaerosol threats and unknown aerosols with similar characteristics. When testing biodetectors, the biosimulant used must maintain the typical size range of bioaerosol threats (1 to 10 micro-meter) and have fluorescent labeling adequate for detection. Typical biosimulants used for this purpose are spore surrogates for Bacillus anthracis or fluorescent-labeled synthetic polymer beads. While anthrax spore surrogates including B. atrophaeus (formerly B. globigii) and B. subtillis provide the complex fluorescence spectrum associated with biological threat agents and synthetic beads provide spectral customization, both have limited use in high traffic areas due to safety concerns. Prepared from food-grade saccharides safe for human exposure as the bulk material, these particles are demonstrated to have the desired morphology and tunable fluorescence.
To achieve the tunable emission spectra, several fluorophores were combined in various amounts according to simple algorithms. The resulting combinations shift the wavelengths of the major peaks observed when using a 266 nm excitation wavelength. The fluorescent intensity of each particle was also tunable by adjusting the amount of the fluorophore tags added while keeping the ratio of fluorophores constant. This presentation will discuss the utilized particle production and fluorescent characterization methodologies.
Prepared by LLNL under Contract DE-AC52-07NA27344. LLNL IM release number LLNL-ABS-652614.