Single-Bacterial Profiling and Identification Based on Quantitative Phase Imaging

Abstract

Rapid identification of bacterial species is crucial in medicine and food hygiene. For instance, bacterial invasion-related syndromes such as sepsis, pneumonia, abscess, meningitis, gastroenteritis and food poisoning require rapid cures which are appropriate for the invaded bacterial species. However, conventional culture-based or molecular-assay technologies do not match this time requirement in general, mainly due to their limited sensitivity. Here, we present the potential of quantitative phase imaging (QPI) techniques (1) for identification of bacterial species at single bacterium level. Employment of various QPI modalities provides the corresponding biophysical and biochemical properties of the bacterial cell in a rapid and label-free manner. First, we employed anisotropic Fourier transform light scattering (2) and demonstrated that light scattering from individual bacterium reflects structural information sufficient for identification of rod-shaped species. Second, the potential of spectroscopic QPI (3, 4) for extracting chemical composition of the bacterium with sub-genus sensitivity is suggested.1. Lee, K., K. Kim, J. Jung, J. H. Heo, S. Cho, S. Lee, G. Chang, Y. J. Jo, H. Park, and Y. K. Park. 2013. Quantitative phase imaging techniques for the study of cell pathophysiology: from principles to applications. Sensors 13:4170-4191.2. Kim, Y., J. M. Higgins, R. R. Dasari, S. Suresh, and Y. K. Park. 2012. Anisotropic light scattering of individual sickle red blood cells. J. Biomed. Opt. 17:040501.3. Park, Y., T. Yamauchi, W. Choi, R. Dasari, and M. S. Feld. 2009. Spectroscopic phase microscopy for quantifying hemoglobin concentrations in intact red blood cells. Optics Letters 34:3668-3670.4. Jang, Y., J. Jang, and Y. Park. 2012. Dynamic spectroscopic phase microscopy for quantifying hemoglobin concentration and dynamic membrane fluctuation in red blood cells. Optics Express 20.