Paper
17 October 2006 Study of bacteria by spectroscopic techniques
Vidhu S. Tiwari, Chan Kyu Kim, Fang-Yu Yueh, Jagdish P. Singh, Michael Cunningham Jr., Lakshmi Pulakat, Nara Gavini, Paresh Chandra Ray
Author Affiliations +
Abstract
Raman and Laser Induced Fluorescence (LIF) spectroscopic techniques were used for studying Azotobacter vinelandii- a genus of free-living diazotrophic soil bacteria. Azotobacter has generated a great deal of interest owing to their unique mode of metabolism. It is a large, obligately aerobic soil bacterium, which has one of the highest respiratory rates known among living organisms and is able to grow on a wide variety of carbohydrates, alcohols and organic acids. The Raman Scattering of Azotobacter, incubated with gold nanoparticles, was examined with 532-nm as an excitation laser wavelength. The basic instrumentation for characterizing the bacteria by Raman spectroscopy employed a continuous wave (CW) frequency doubled Nd: YAG laser (532-nm) and a modified In-Photonics fiber optic state-of-art miniaturized Raman Probe. The surface enhancement effects allowed the observation of Raman spectra of such bacterial cells, and were excited in the visible region of wavelength at low incident power for minimum sample degradation. LIF spectra of Azotobacter were measured with a 410-nm CW diode laser as an excitation source, and a reflection probe to deliver laser beam on the sample and collect the LIF signal from the sample. Spectral contrast observed in gold particles conjugated bacteria, from nitrogen fixing and non-nitrogen fixing condition was analyzed for characterizing the bacteria cells, and the results are presented in the paper.
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Vidhu S. Tiwari, Chan Kyu Kim, Fang-Yu Yueh, Jagdish P. Singh, Michael Cunningham Jr., Lakshmi Pulakat, Nara Gavini, and Paresh Chandra Ray "Study of bacteria by spectroscopic techniques", Proc. SPIE 6377, Advanced Environmental, Chemical, and Biological Sensing Technologies IV, 637709 (17 October 2006); https://doi.org/10.1117/12.685557
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KEYWORDS
Raman spectroscopy

Gold

Bacteria

Nanoparticles

Laser induced fluorescence

Spectroscopy

Luminescence

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