Bioaerosol analysis with Raman chemical imaging microspectroscopy.
Raman chemical imaging microspectroscopy is evaluated as a technology for waterborne pathogen and bioaerosol detection. Raman imaging produces a three-dimensional data cube consisting of a Raman spectrum at every pixel in a microscope field of view. Binary and ternary mixtures including combinations of polystyrene beads, gram-positive Bacillus anthracis, B. thuringiensis, and B. atrophaeus spores, and B. cereus vegetative cells were investigated by Raman imaging for differentiation and characterization purposes. Bacillus spore aerosol sizes were varied to provide visual proof for corroboration of spectral assignments. Conventional applications of Raman imaging consist of differentiating relatively broad areas of a sample in a microscope field of view. The spectral angle mapping data analysis algorithm was used to compare a library spectrum with experimental spectra from pixels in the microscope field of view. This direct one-to-one matching is straightforward, does not require a training set, is independent of absolute spectral intensity, and only requires univariate statistics. Raman imaging is expanded in its capabilities to differentiate and distinguish between discrete 1-6 microm size bacterial species in single particles, clusters of mixed species, and bioaerosols with interference background particles.
Tripathi
Ashish
A
Science Applications International Corp., P.O. Box 68, Gunpowder Branch, Aberdeen Proving Ground, Maryland 21010-5424, USA.
Jabbour
Rabih E
RE
Guicheteau
Jason A
JA
Christesen
Steven D
SD
Emge
Darren K
DK
Fountain
Augustus W
AW
Bottiger
Jerold R
JR
Emmons
Erik D
ED
Snyder
A Peter
AP
D000336:Aerosols; D000465:Algorithms; D001407:Bacillus / Q000166:cytology; D013059:Spectrum Analysis, Raman / Q000379:methods*
D000336:Aerosols