Regular Article

Theoretical Chemistry Accounts

, Volume 130, Issue 4, pp 1261-1273

First online:

Overview of the use of theory to understand infrared and Raman spectra and images of biomolecules: colorectal cancer as an example

  • J. A. A. C. PivaAffiliated withLaboratory of Biomedical Vibrational Spectroscopy, Institute of Research and Development, Universidade do Vale do Paraíba, UniVaP
  • , J. L. R. SilvaAffiliated withLaboratory of Biomedical Vibrational Spectroscopy, Institute of Research and Development, Universidade do Vale do Paraíba, UniVaP
  • , L. RanieroAffiliated withLaboratory of Biomedical Vibrational Spectroscopy, Institute of Research and Development, Universidade do Vale do Paraíba, UniVaP
  • , A. A. MartinAffiliated withLaboratory of Biomedical Vibrational Spectroscopy, Institute of Research and Development, Universidade do Vale do Paraíba, UniVaP Email author 
  • , H. G. BohrAffiliated withDepartment of Physics, Quantum Protein Center, QuP, Technical University of Denmark
  • , K. J. JalkanenAffiliated withLaboratory of Biomedical Vibrational Spectroscopy, Institute of Research and Development, Universidade do Vale do Paraíba, UniVaPDepartment of Physics, Quantum Protein Center, QuP, Technical University of DenmarkDivision of Functional Genome Analysis, German Cancer Research Center (DKFZ) Email author 

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Abstract

In this work, we present the state of the art in the use of theory (first principles, molecular dynamics, and statistical methods) for interpreting and understanding the infrared (vibrational) absorption and Raman scattering spectra. It is discussed how they can be used in combination with purely experimental studies to generate infrared and Raman images of biomolecules in biologically relevant solutions, including fluids, cells, and both healthy and diseased tissue. The species and conformers of the individual biomolecules are in many cases not stable structures, species, or conformers in the isolated state or in non-polar non-strongly interacting solvents. Hence, it is better to think of the collective behavior of the system. The collective interaction is not the simple sum of the individual parts. Here, we will show that this is also not true for the infrared and Raman spectra and images and that the models used must take this into account. Hence, the use of statistical methods to interpret and understand the infrared and Raman spectra and images from biological tissues, cells, parts of cells, fluids, and even whole organism should change accordingly. As the species, conformers and structures of biomolecules are very sensitive to their environment and aggregation state, the combined use of infrared and Raman spectroscopy and imaging and theoretical simulations are clearly fields, which can benefit from their joint and mutual development.

Keywords

Infrared Raman First principles Molecular mechanics Statistical methods Principal component analysis Linear discriminant analysis Cluster analysis Infrared imaging Raman imaging Image generation Colorectal cancer diagnosis