An Interpretation Model For The UV-VIS Spectra Of Microorganisms

Multiwavelength UV-vis spectra of microorganisms and cell suspensions contain quantitative information on their properties such as number, size, shape, chemical composition, and internal structure. These properties are essential for the identification and classification of cells. The complexity of microorganisms in terms of their chemical composition and internal structure makes the interpretation of their spectral signature a difficult task. In this article a model is proposed for the interpretation of the multiwavelength spectra of microorganisms. The proposed interpretation model is based on light scattering theory, spectral deconvolution techniques, and the approximation of the frequency-dependent optical properties of the basic constituents of living organisms. The optical properties as functions of wavelength and available literature data on the size and chemical composition of E. coli cells and Bacillus globigii spores were used to explore the sensitivity of the calculated spectra to the model parameters. It is shown that the proposed model can reproduce the features of experimentally measured spectra. The sensitivity of the spectra to the model parameters suggests that the proposed model can be used for the quantitative deconvolution of the UV-vis spectra in terms of critical information necessary for the detection and identification of microorganisms. Key Words: BiosensorMultiwavelength spectroscopyAbsorbanceScatteringDeconvolutionOptical propertiesMie theory E. coli B. globigii Acknowledgments The authors would like to acknowledge the support of Los Alamos National Laboratory, (Los Alamos National Laboratory is operated by the University of California for the U.S. Department of Energy under contract no. W-7406-ENG-36), the American Water Works Research Foundation, and the Engineering Research Center (ERC) for Particle Science and Technology at the University of Florida through the National Science Foundation (NSF) grant #EEC-94-02989. Notes aB. cereus, Ross and Billing (1957). aValues from Bergey's Manual of Determinative Bacterology (1993), Williams & Wilkins, Baltimore. bValues from Los Alamos National Laboratory. chttp://esg-www.mit.edu:8001/esgbio/cb/ecoli.html dDoi, (1969), in The Bacterial Spores, 131, Academic Press, New York. eMurrell, (Citation1969), in The Bacterial Spores, 250, Academic Press, New York.