Phase behavior and glass transition of 1,2-dioleoylphosphatidylethanolamine (DOPE) dehydrated in the presence of sucrose

Biochim Biophys Acta. 2001 Sep 3;1514(1):100-16. doi: 10.1016/s0005-2736(01)00372-8.


The effect of sucrose on the phase behavior of 1,2-dioleoylphosphatidylethanolamine (DOPE) as a function of hydration was studied using differential scanning calorimetry and X-ray diffraction. DOPE/sucrose/water dispersions were dehydrated at osmotic pressures (Pi) ranging from 2 to 300 MPa at 30 degrees C and 0 degrees C. The hexagonal II-to-lamellar gel (H(II)-->L(beta)) thermotropic phase transition was observed during cooling in mixtures dehydrated at Pi<or=35 MPa. After dehydration at Pi>or=57 MPa, the H(II)-->L(beta) thermotropic phase transition was precluded when sucrose entered the rigid glassy state while the lipid was in the H(II) phase. Sucrose also hindered the H(II)-to-lamellar crystalline (L(c)), and H(II)-to-inverted ribbon (P(delta)) lyotropic phase transitions, which occurred in pure DOPE. Although the L(c) phase was observed in dehydrated 2:1 (mole ratio) DOPE/sucrose mixtures, it did not form in mixtures with higher sucrose contents (1:1 and 1:2 mixtures). The impact of sucrose on formation of the ordered phases (i.e., the L(c), L(beta), and P(delta) phases) of DOPE was explained as a trapping of DOPE in a metastable H(II) phase due to increased viscosity of the sucrose matrix. In addition, a glass transition of DOPE in the H(II) phase was observed, which we believe is the first report of a glass transition in phospholipids.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Calorimetry, Differential Scanning
  • Liposomes
  • Osmotic Pressure
  • Phosphatidylethanolamines / chemistry*
  • Solutions
  • Sucrose / chemistry*
  • Temperature
  • Thermodynamics
  • X-Ray Diffraction


  • Liposomes
  • Phosphatidylethanolamines
  • Solutions
  • Sucrose
  • 1,2-dielaidoylphosphatidylethanolamine