Detecting Bacillus cereus spores on a mail sorting system using Raman spectroscopy

Abstract

The ability of Raman spectroscopy to detect anthrax-causing spores as they pass through a mail sorting system was investigated. A pump was connected to an existing vacuum manifold on a commercial sorter, and a filter designed to capture 0.5-3 µm particles was placed in-line. A standard business letter containing 0.23 g of Bacillus cereus spores, a Bacillus anthracis surrogate, was placed in a stack of 20 letters and passed through the system. Raman spectra of the filter positively identified the captured material as bacterial spores by the dominant calcium dipicolinate Raman spectral bands associated with the spore core. A limit of detection, using 400 mW of 785 nm laser excitation for a 1-s acquisition, is estimated at 4.5 mg. The ability of a Raman spectroscopy based system to detect and prevent the distribution of a letter containing gram levels of anthrax spores is discussed.

Detection of Bacillus Spores by Surface-Enhanced Raman Spectroscopy

“…The primary CaDPA peaks occur at 659,821,1014,1391,1446,1573,3062, and 3080 cm -1 in the spore spectrum (Fig. 2), and can be assigned to a ring CC bend, an out-of-plane CH bend, the symmetric pyridine ring stretch, a symmetric OCO stretch, a symmetric ring CH bend, an asymmetric OCO stretch, and the CH symmetric and asymmetric stretches, respectively (Table 1, Farquharson et al, 2004). www.intechopen.com…”

“…However, the spectrum was collected using pure spores and took hours to acquire. Since that time, considerable improvements in Raman instrumentation have led to laboratory measurements of single Bacillus spores and field measurements of spores captured from a mail sorting system (Esposito et al, 2003;Farquharson et al, 2004). Unfortunately, the single spore measurements required the use of a microscope system and time consuming efforts to locate the spores, while the field measurements required milligrams of sample.…”

Bio-organism sensing via surface enhanced Raman spectroscopy on controlled metal/polymer nanostructured substrates

“…As these feature sizes decrease to the limit of the atomic scale the SPP resonances are dramatically enhanced, leading to extraordinarily large local electromagnetic fields which, in turn, leads to huge magnifications of the Raman scattering signals of molecules located at the local feature ͑hot spot͒. The combination of the high sensia͒ Authors to whom correspondence should be addressed; electronic addresses: mdemirel@engr.psu.edu and dla3@psu.edu tivity and the fingerprint spectral capability of SERS has led to interest in a broad variety of biomedical types of applications including rapid DNA sequencing, 11 pathogen detection, 12 and food analysis. 13 Of particular interest to us has been the potential ability of SERS to obtain vibrational spectra from surface collected pathogens that could be used for detection and identification without reagents and further provides the chemical composition of pathogen membranes, which then could serve as a highly specific identification marker.…”

Early Warning of Biological Threats via Surface-Enhanced Raman Spectroscopy: A Case Study of Bacillus Spores

“…It could be explained by the possibility of having some components of spores, as well as the functional group of the main component of Bacillus spores, in solution. [29,32,33] In particular, the signal at 1650 cm −1 can be attributed to the amide II combination modes and the amide I mode (C = O stretch) [17]. Nevertheless, for both kinds of spores, statistical analysis demonstrates the ability to discriminate between Raman spectra before and after spore inoculation and surface rinsing.…”