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Proceedings Paper

Time-resolved and steady-state fluorescence spectroscopy from bacteria subjected to bactericidal agents
Author(s): Alvin Katz; Alexandra Alimova; Masood Siddique; Howard E. Savage; Mahendra Shah; Richard Rosen; Robert Alfano
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Paper Abstract

The time-resolved and steady-state changes in fluorescence were investigated from one spore-forming (Bacillus subtilis) and four non-spore forming (Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, and Pseudomonas aeruginosa) bacteria subjected to different bactericidal agents. The bactericidal agents were sodium hypochlorite (bleach) hydrogen peroxide, formaldehyde, and UV light exposure. Application of sodium hypochlorite resulted in an almost total lose of fluorescence signal and large decrease in the optical density of the bacterial suspension. Addition of hydrogen peroxide resulted in a 35% decrease in emission intensity fom the Sa and an 85-95% decrease for the other bacteria. Ultraviolet light exposure resulted in a 5-35% decrease in the emission intensity of the tryptophan band. The addition of formaldehyde to the bacteria did not result in significant changes in the steady-state emission intensity, but did shift the tryptophan emission peak position to shorter wavelengths by 3 to 5 nm. Time-resolved fluorescence measurements showed that the fluorescence lifetime of tryptophan in the bacteria could not be described by a single exponential decay, and was similar to that of tryptophan in neutral aqueous solution. Upon addition of formaldehyde to the Gram positive bacteria (Bs and Sa) the strength of the short lifetime component increased dramatically, while for the Gram negative bacteria, a smaller increase was observed. These fluorescence changes reflect the different mechanisms of the bactericidal agents and may provide a useful tool to monitor the effectiveness of disinfectants.

Paper Details

Date Published: 8 March 2004
PDF: 4 pages
Proc. SPIE 5269, Chemical and Biological Point Sensors for Homeland Defense, (8 March 2004); doi: 10.1117/12.518656
Show Author Affiliations
Alvin Katz, City College of New York (United States)
Alexandra Alimova, City College of New York (United States)
Masood Siddique, City College of New York (United States)
Howard E. Savage, New York Eye and Ear Infirmary (United States)
Mahendra Shah, New York Eye and Ear Infirmary (United States)
Richard Rosen, New York Eye and Ear Infirmary (United States)
Robert Alfano, City College of New York (United States)


Published in SPIE Proceedings Vol. 5269:
Chemical and Biological Point Sensors for Homeland Defense
Arthur J. Sedlacek; Richard Colton; Tuan Vo-Dinh, Editor(s)

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