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Atomic Force Microscopy Imaging and Force Spectroscopy of Supported Lipid Bilayers
Published on: July 22, 2015
Domain formation in lipid bilayers probed by two-dimensional infrared spectroscopy
Victor V Volkov1, Riccardo Chelli, Roberto Righini
1European Laboratory for Nonlinear Spectroscopy (LENS), Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy. v.volkov@lens.unifi.it
The Journal of Physical Chemistry. B
|February 14, 2006
Summary
Two-dimensional infrared spectroscopy revealed distinct molecular dynamics and segregation in sphingomyelin/phospholipid liposomes. This suggests the formation of separate sphingomyelin and phospholipid domains within the lipid bilayers.
Area of Science:
- Biophysics
- Spectroscopy
- Lipid Bilayer Research
Background:
- Liposomes are crucial for drug delivery and biological membrane studies.
- Understanding lipid-protein interactions within liposomes is key to their function.
- Sphingomyelin (SPM) and phospholipids (like PLPC) are major membrane components with distinct properties.
Purpose of the Study:
- To investigate the structure and molecular dynamics of binary sphingomyelin/phospholipid liposomes.
- To determine the spatial organization and interactions between SPM and PLPC within liposomes.
- To utilize 2D-IR spectroscopy for probing lipid domain formation.
Main Methods:
- Two-dimensional infrared (2D-IR) spectroscopy was employed.
- The study focused on liposomes composed of 1-palmitoyl-2-linoleyl phosphatidylcholine (PLPC) and sphingomyelin (SPM) at a 1:1 ratio.
- Analysis of diagonal and off-diagonal peaks in the 2D-IR spectra.
Main Results:
- Diagonal 2D-IR spectra showed distinct bands for SPM amide I and PLPC carbonyl groups.
- Differences in spectral features indicated varied molecular dynamics between SPM and PLPC.
- Off-diagonal cross-peaks confirmed intermolecular structural correlations.
- The intensity of cross-peaks supported the segregation of PLPC and SPM into distinct molecular domains.
Conclusions:
- Binary sphingomyelin/phospholipid liposomes exhibit segregation of lipid components into molecular domains.
- 2D-IR spectroscopy is effective in distinguishing lipid dynamics and organization.
- The findings provide insights into the complex structure of lipid bilayers.
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