Ultrasound interaction with large unilamellar vesicles at the phospholipid phase transition: Perturbation by phospholipid side chain substitution with deuterium

Reef Morse, Loralie D. Ma, Richard L. Magin, Floyd Dunn

Research output: Contribution to journalArticle

Abstract

The ultrasonic absorption, αλ, as a function of temperature and frequency was determined in large unilamellar vesicles (LUVs) in which specific phospholipid side chains were deuterated. Deuteration significantly altered the temperature and frequency dependence of αλ. The frequency change was especially marked, with decreased frequency and broadening of the ultrasound relaxation, even with only minor changes in the phase transition temperature. Deuteration decreased the T(m) and enthalpy of the lipid phase transition, as shown by differential scanning calorimetry, whereas electron spin resonance showed that at and above the lipid phase transition, no differences in the mobility as a function of temperature were observed. These results show that the observed increase in ultrasonic absorption in LUVs at the phospholipid phase transition arises from the interaction of ultrasound with the hydrophobic side chains, probably coupling with structural reorganization of small domains of molecules, a process which is maximized at the phase transition temperature. Copyright (C) 1999 Elsevier Science Ireland Ltd.

Original languageEnglish (US)
Pages (from-to)1-10
Number of pages10
JournalChemistry and Physics of Lipids
Volume103
Issue number1-2
DOIs
StatePublished - Dec 1999
Externally publishedYes

Keywords

  • Large unilamellar vesicles
  • Phospholipid phase transition
  • Ultrasound interaction

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics

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