A detailed analysis of partial molecular volumes in DPPC/cholesterol binary bilayers

T Miyoshi, Max Lönnfors, J Peter Slotte, S Kato

    Research output: Contribution to journalArticleScientificpeer-review

    16 Citations (Scopus)


    We examined the volumetric behavior of the dipalmitoylphosphatidylcholine (DPPC)/cholesterol binary bilayer system with high accuracy and more cholesterol concentrations to reveal the detailed molecular states in the liquid-disordered (Ld) phase, the liquid-ordered (Lo) phase and the gel phase. We measured the average specific volume of the binary bilayer at several temperatures by the neutral flotation method and calculated the average volume per molecule to estimate the partial molecular volumes of DPPC and cholesterol in each phase. As a result, we found that the region with intermediate cholesterol concentrations showed a more complicated behavior than expected from simple coexistence of Ld and Lo domains. We also measured fluorescence decay of trans-parinaric acid (tPA) added into the binary bilayer with more cholesterol concentrations to get further insight into the cholesterol-induced formation of the Lo phase. On the basis of these results we discuss the molecular interaction between DPPC and cholesterol molecule in the Lo phase and the manner of Ld/Lo phase coexistence.

    Original languageUndefined/Unknown
    Pages (from-to)3069–3077
    JournalBBA - Biomembranes
    Issue number12
    Publication statusPublished - 2014
    MoE publication typeA1 Journal article-refereed

    Cite this