Calcium-induced domain formation in mixed lipid monolayers

ORAL

Abstract

Multivalent ions such as calcium play an important role in soft matter and biological systems. This role cannot be captured by a mean field treatment of the electrostatics such as the Poisson-Boltzmann equation, which neglects, for example, the fact that Ca$^{2+}$-ions can mediate attractions between negatively-charged objects. We show, both experimentally and theoretically, that Ca$^{2+}$-mediated attractions lead to phase separation of charged and neutral lipid molecules in mixed lipid monolayers, and discuss the dependence on pH, salt concentration and ion valency.

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Authors

  • Wouter Ellenbroek

    Department of Physics and Astronomy, University of Pennsylvania, University of Pennsylvania

  • David A. Christian

    MRSEC, University of Pennsylvania, University of Pennsylvania, Chemical \& Biomolecular Eng'g and the Laboratory for Research on the Structure of Matter, University of Pennsylvania

  • Ilya Levental

    Institute for Medicine and Engineering, University of Pennsylvania

  • Andrea J. Liu

    Department of Physics, University of Pennsylvania, University of Pennsylvania, Department of Physics and Astronomy, University of Pennsylvania

  • Paul A. Janmey

    University of Pennsylvania, Departments of Physics and Astronomy, and Bioengineering, University of Pennsylvania