Molecular Composition and Orientation in Myelin Figures Characterized by Coherent Anti-Stokes Raman Scattering Microscopy

Abstract

The molecular organization inside myelin figures of various surfactants are studied by laser scanning coherent anti-Stokes Raman scattering (CARS) microscopy that permits three-dimension vibrational imaging. The resonant CARS signals from CH2 and H2O stretch vibrations are used to probe the surfactant and water molecules inside the myelin figures formed of C12E3, lecithin, and Aerosol OT. The polarization sensitivity of CARS is used to analyze the orientation of the CH2 groups and the H2O molecules. The CARS images suggest that the myelin figure is a concentric lamellar structure with alternating surfactant bilayers and partially ordered water layers. No sizable water core is observed in the CARS images at the lateral resolution of 0.3 microm and the axial resolution of 0.75 microm. The CARS data are verified by confocal fluorescence microscopy with FITC and DOPE-rhodamine labeling the water and bilayers, respectively. The relationship between the molecular composition and ordering inside the myelin figures and the surfactant structure has been investigated.

Realignment-enhanced coherent anti-Stokes Raman scattering and three-dimensional imaging in anisotropic fluids

“…The main advantage of CARS over fluorescence microscopy is that no special dye staining is necessary because CARS utilizes Raman scattering from studied chemicals with specific vibration resonances. Chemically-selective imaging of molecular orientations in biological and lyotropic systems by CARS microscopy has been recently reported [8][9][10][11][12][13][14][15][16]. This technique has allowed for nondestructive visualization of both chemical composition and molecular orientations in the heterogeneous systems.…”

Dissolution Rates of Surfactants

“…Electron micrographs [24,26] showed that each tubular myelinic figure in the egg-yolk phosphatidylcholine/water system consisted of a water core surrounded by many concentric bilayers. More recently Raman spectroscopy techniques have confirmed the concentric bilayer arrangement [1,18]. Myelinic figures are not equilibrium structures, however, and eventually break up to form vesicles or other lamellar structures.…”

Principles of nonlinear microscopy and application possibilities in dermatology

“…Ráadásul ennél a módszernél arra sincs szükség, hogy azok természetes fluoreszcenciával rendelkezzenek (30). A módszer segítségével számos biológiai mintázat azonosítható, mint például a lipid kettôs rétegek (31), zsírsejtek (32), víz (33), DNS (34) vagy az idegsejteket burkoló myelinhüvely (35). A bôr vizsgálata során a CARS mikroszkópia alkalmas lehet az intracelluláris lipidek, vagy a szubkutisban található zsírsej-tek (2f.…”