Phase structure of liposome in lipid mixtures

Tianxi Zhang, Yuzhuo Li, Anja Mueller

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Gas microbubbles present in ultrasound imaging contrast agents are stabilized by lipid aggregates that typically contain a mixture of lipids. In this study, the phase structure of the lipid mixtures that contained two or three lipids was investigated using three different methods: dynamic light scattering, 1H NMR, and microfluidity measurements with fluorescence probes. Three lipids that are commonly present in imaging agents (DPPC, DPPE-PEG, and DPPA) were used. Two types of systems, two-lipid model systems and simulated imaging systems were investigated. The results show that liposomes were the dominant aggregates in all the samples studied. The polar PEG side chains from the PEGylated lipid lead to the formation of micelles and micellar aggregates in small sizes. In the ternary lipid systems, almost all the lipids were present in bilayers with micelles absent and free lipids at very low concentration. These results suggest that liposomes, not micelles, contribute to the stabilization of microbubbles in an ultrasound imaging contrast agent.

Original languageEnglish
Pages (from-to)722-726
Number of pages5
JournalChemistry and Physics of Lipids
Issue number8
StatePublished - Nov 2011


  • Aggregation
  • Lipids
  • Liposome
  • Phase structure
  • Ultrasound image


Dive into the research topics of 'Phase structure of liposome in lipid mixtures'. Together they form a unique fingerprint.

Cite this