Number of free hydroxyl groups on bile acid phospholipids determines the fluidity and hydration of model membranes

J Phys Chem B. 2013 Oct 10;117(40):12135-44. doi: 10.1021/jp406340y. Epub 2013 Sep 30.

Abstract

Interactions of synthetic phospholipids with model membranes determines the drug release capabilities of phospholipid vesicles at diseased sites. We performed 1,6-diphenyl-1,3,5-hexatriene (DPH)-based fluorescence anisotropy, Laurdan-based membrane hydration, and differential scanning calorimetry (DSC) studies to cognize the interactions of three bile acid phospholipids, lithocholic acid-phosphocholine (LCA-PC), deoxycholic acid-phosphocholine (DCA-PC), and cholic acid-phosphocholine (CA-PC) with model membranes. These studies revealed that bile acid phospholipids increases membrane fluidity in DCA-PC > CA-PC > LCA-PC order, indicating that induction of membrane fluidity is contingent on the number and positioning of free hydroxyl groups on bile acids. Similarly, DCA-PC causes maximum membrane perturbations due to the presence of a free hydroxyl group, whereas LCA-PC induces gel phase in membranes due to hydrophobic bile acid acyl chain interactions. These DCA-PC-induced membrane perturbations induce a drastic decrease in phase transition temperature (Tm) as determined by calorimetric studies, whereas doping of LCA-PC causes phase transition broadening without change in Tm. Doping of CA-PC induces membrane perturbations and membrane hydration like DCA-PC but sharpening of phase transition at higher doping suggests self-association of CA-PC molecules. Therefore these differential mode of interactions between bile acid phospholipids and model membranes would help in the future for their use in drug delivery.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 2-Naphthylamine / analogs & derivatives
  • 2-Naphthylamine / chemistry
  • Bile Acids and Salts / chemistry*
  • Calorimetry, Differential Scanning
  • Cholic Acid / chemistry
  • Deoxycholic Acid / chemistry
  • Diphenylhexatriene / chemistry
  • Fluorescence Polarization
  • Laurates / chemistry
  • Liposomes / chemistry
  • Lithocholic Acid / chemistry
  • Membrane Fluidity
  • Models, Molecular*
  • Phase Transition
  • Phospholipids / chemistry*
  • Transition Temperature

Substances

  • Bile Acids and Salts
  • Laurates
  • Liposomes
  • Phospholipids
  • Deoxycholic Acid
  • Diphenylhexatriene
  • Lithocholic Acid
  • 2-Naphthylamine
  • Cholic Acid
  • laurdan