Teraherz vibrational spectroscopy of E. coli and molecular constituents: Computational modeling and experiment

In this paper we present the results of our research of E. coli cells and cellular components, DNA and protein thioredoxin, using highly resolved sub-Terahertz (THz) vibrational spectroscopy. In this combined research, the results from experimental spectroscopy are analyzed via molecular dynamics (MD) simulation of vibrational modes and absorption spectra from E. coli cells and constituents in the sub-THz range. Simplified models of DNA macromolecules with a short sequencing have been constructed for several E. coli strains with the goal to predict their absorption spectra. The similarity between spectral characteristics of E. coli cells and cellular components observed in experiments helps us to better understand the mechanism of material interaction with THz radiation and to add genetic information to the characteristic signatures from biological objects. Modeling results supported by experimental characterization using a spectroscopic sensor prototype developed and built by Vibratess confirm that an optical, label and reagent free technique can be used to examine, detect, and identify bacterial cells with high accuracy and selectivity to the level of strains.