Terahertz vibrational signature of bacterial spores arising from nanostructure decorated endospore surface |
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| Authors: | Debopam Datta Michael A. Stroscio Mitra Dutta Weidong Zhang Elliott R. Brown |
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| Affiliation: | 1. Department of Electrical and Computer Engineering, University of Illinois at Chicago, Chicago, Illinois;2. Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois;3. Department of Physics, University of Illinois at Chicago, Chicago, Illinois;4. Department of Physics and Electrical Engineering, Wright State University, Dayton, Ohio |
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| Abstract: | This theoretical effort is the first to explore the possible hypothesis that terahertz optical activity of Bacillus spores arises from normal vibrational modes of spore coat subcomponents in the terahertz frequency range. Bacterial strains like Bacillus and Clostridium form spores with a hardened coating made of peptidoglycan to protect its genetic material in harsh conditions. In recent years, electron microscopy and atomic force microscopy has revealed that bacterial spore surfaces are decorated with nanocylinders and honeycomb nanostructures. In this article, a simple elastic continuum model is used to describe the vibration of these nanocylinders mainly in Bacillus subtilis, which also leads to the conclusion that the terahertz signature of these spores arises from the vibration of these nanostructures. Three vibrating modes: radial/longitudinal, torsional and flexural, have been identified and discussed for the nanocylinders. The effect of bound water, which shifts the vibration frequency, is also discussed. The peptidoglycan molecule consists of polar and charged amino acids; hence, the sporal surface local vibrations interact strongly with the terahertz radiation.  |
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| Keywords: | biological nanostructures elastic continuum model peptidoglycan tessera phonons in biology terahertz vibrations in bacterial spore |
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