Pathogen detection using Raman spectroscopy is achieved through the use of a sandwich
immunoassay. Antibody-modified magnetic beads are used to capture and concentrate target
analytes in solution and surface-enhanced Raman spectroscopy (SERS) tags are conjugated with
antibodies and act as labels to enable specific detection of biological pathogens. The rapid detection
of biological pathogens is critical to first responders, thus assays to detect E.Coli and Anthrax have
been developed and will be reported. The problems associated with pathogen detection resulting
from the spectral complexity and variability of microorganisms are overcome through the use of
SERS tags, which provide an intense, easily recognizable, and spectrally consistent Raman signal.
The developed E. coli assay has been tested with 5 strains of E. coli and shows a low limit of
detection, on the order of 10 and 100 c.f.u. per assay. Additionally, the SERS assay utilizes
magnetic beads to collect the labeled pathogens into the focal point of the detection laser beam,
making the assay robust to commonly encountered white powder interferants such as flour, baking
powder, and corn starch. The reagents were also found to be stable at room temperature over
extended periods of time with testing conducted over a one year period. Finally, through a
specialized software algorithm, the assays are interfaced to the Raman instrument, StreetLab
Mobile, for rapid-field-deployable biological identification.