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Proceedings Paper

Vibrational fingerprinting of bacterial pathogens by surface enhanced Raman scattering (SERS)
Author(s): W. Ranjith Premasiri; D. T. Moir; Lawrence D. Ziegler
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Paper Abstract

The surface enhanced Raman scattering (SERS) spectra of vegetative whole-cell bacteria were obtained using in-situ grown gold nanoparticle cluster-covered silicon dioxide substrates excited at 785 nm. SERS spectra of Gram-negative bacteria; E. coli and S. typhimurium, and Gram-positive bacteria; B. subtilis, B. cereus, B. thuringeinsis and B. anthracis Sterne, have been observed. Raman enhancement factors of ~104-105 per cell are found for both Gram positive and Gram negative bacteria on this novel SERS substrate. The bacterial SERS spectra are species specific and exhibit greater species differentiation and reduced spectral congestion than their corresponding non-SERS (bulk) Raman spectra. Fluorescence observed in the 785 nm excited bulk Raman emission of Bacillus species is not apparent in the corresponding SERS spectra. The surface enhancement effect allows the observation of Raman spectra at the single cell level excited by low incident laser powers (< 3 mW) and short data acquisition times (~20 sec.). Comparison with previous SERS studies suggests that these SERS vibrational signatures are sensitively dependent on the specific morphology and nature of the SERS active substrate. Exposure to biological environments, such as human blood serum, has an observable effect on the bacterial SERS spectra. However, reproducible, species specific SERS vibrational fingerprints are still obtained. The potential of SERS for detection and identification of bacteria with species specificity on these gold nanoparticle coated substrates is demonstrated by these results.

Paper Details

Date Published: 12 May 2005
PDF: 11 pages
Proc. SPIE 5795, Chemical and Biological Sensing VI, (12 May 2005); doi: 10.1117/12.605742
Show Author Affiliations
W. Ranjith Premasiri, Boston Univ. (United States)
D. T. Moir, Microbiotix, Inc. (United States)
Lawrence D. Ziegler, Boston Univ. (United States)

Published in SPIE Proceedings Vol. 5795:
Chemical and Biological Sensing VI
Patrick J. Gardner, Editor(s)

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