Related Experiment Video
Updated: Aug 23, 2026

Biomembrane Fabrication by the Solvent-assisted Lipid Bilayer (SALB) Method
Published on: December 1, 2015
Effects of ethanol on lipid bilayers with and without cholesterol: the distearoylphosphatidylcholine system
Rosalie Tran1, Shirleen Ho, Phoebe Dea
1Department of Chemistry, Occidental College, 1600 Campus Road, Los Angeles, CA 90041, USA.
Abstract:
Differential scanning calorimetry (DSC) and fluorescence spectroscopy are useful techniques for investigating the phase transitions of phospholipid bilayers. In this study, these methods have been extended to determine the effects of ethanol on DSPC and DSPC/2 mol.% cholesterol bilayers. The biphasic effect of the main transition was observed on the DSC heating scans above 0.60 M ethanol. In addition, the concentration at which the biphasic effect occurs is not significantly changed in the presence of 2 mol.% cholesterol. For the fluorescence studies, 1,6-diphenyl-1,3,5-hexatriene (DPH) has been incorporated into the bilayer to monitor the phase transitions through the displacement of DPH. This fluorescent probe is used to directly determine the onset of interdigitation in the bilayer systems as indicated by a large decrease in the DPH fluorescence intensity. The addition of cholesterol lowered and broadened the transition temperatures of the phosphatidylcholine (PC) system. However, 2 mol.% cholesterol did not have a significant effect on the induction of the interdigitated phase in DSPC as observed from the small difference in ethanol threshold concentration for the two systems. This suggests that DSPC forms a more stable interdigitated gel phase than other PCs with shorter acyl chains.
Related Concept Videos
Asymmetric Lipid Bilayer
Synthesis of Phosphatidylcholine in the ER Membrane
The major components of all eukaryotic cell...
Overview of Fatty Acid Metabolism
Fatty acids are catabolized in a process called beta-oxidation, which takes place in the matrix of the mitochondria and converts their fatty acid chains into two-carbon units of acetyl groups. The acetyl...
Membrane Fluidity
Mosaic nature of the membrane
The mosaic characteristic of the membrane helps the plasma membrane remain fluid. The integral proteins and lipids exist as separate but loosely-attached molecules in the membrane. The membrane is a relatively...
Membrane Fluidity
Assembly of the Lipid Bilayer in the ER
A large chunk of any biological membrane is composed of phospholipids. These lipids have a heterogeneous distribution across different subcellular organelles and even between...

