Molecular orientational order probed by coherent anti-Stokes Raman scattering (CARS) and stimulated Raman scattering (SRS) microscopy: a spectral comparative study

J Phys Chem B. 2015 Feb 19;119(7):3242-9. doi: 10.1021/jp5113813. Epub 2015 Jan 30.

Abstract

We investigate how to extract information on the orientational order of molecular bonds in biological samples from polarized coherent anti-Stokes Raman scattering (CARS) and stimulated Raman scattering (SRS) microscopy. Experimentally, the mean orientation of the molecular angular distribution, as well as its second and fourth orders of symmetry, are estimated by monitoring intensity signals under a varying incident polarization. We provide a generic method of analysis of polarized signals in both CARS and SRS contrasts, and apply it to imaging of lipid bonds' orientational order in multilamellar vesicles. A comparison of the two contrasts in the lipid region around 3000 cm(-1) shows that while SRS allows retrieving pure molecular order information, CARS is generally tainted by a bias from the nonresonant contribution.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 1,2-Dipalmitoylphosphatidylcholine / analogs & derivatives
  • 1,2-Dipalmitoylphosphatidylcholine / chemistry
  • Membranes, Artificial
  • Microscopy / methods*
  • Nonlinear Dynamics
  • Spectrum Analysis, Raman / methods*

Substances

  • Membranes, Artificial
  • 1,2-Dipalmitoylphosphatidylcholine
  • colfosceril palmitate