Simulating Lipid Vesicles

Liposomes, or vesicles, are widely used in in vitro studies as mimics of either complete cells or cell organelles such as endosomes or transport vesicles involved in endo- or exocytosis and protein trafficking. In the realm of synthetic biology they furthermore play an important role as drug carriers, sensors and many more potential applications only limited by imagination.

The coarse grained Martini model allows us to study small vesicles at near atomic detail. In an ongoing series of projects we and others have looked at the self-assembly of these vesicles [3,4], the effect of the curved geometry on lipid packing and transmonolayer lipid distribution [2,4], the fusion of vesicles [5], the freezing process [1], and structural properties of crystalline vesicles composed of ionic amphiphiles [7].

The effect of a hypo-osmotic shock on a vesicle has also been simulated, both for pure lipid vesicles and for vesicles equipped with a mechano-sensitive channel [6].

  • [1] H.J. Risselada, S.J. Marrink. The freezing process of small lipid vesicles at molecular resolution. Soft Matter, 5:4531-4541, 2009.
  • [2] H.J. Risselada, S.J. Marrink. Curvature effects on lipid packing and dynamics in liposomes revealed by coarse grained molecular dynamics simulations. Phys. Chem. Chem. Phys., 11:2056-2067, 2009.
  • [3] H.J. Risselada, A.E. Mark, S.J. Marrink. The application of mean field boundary potentials in simulations of lipid vesicles. JPC-B, 112:7438-7447, 2008.
  • [4] S.J. Marrink, A.E. Mark. Molecular dynamics simulation of the formation, structure, and dynamics of small phospholipid vesicles. JACS, 125:15233-15242, 2003.
  • [5] S.J. Marrink, A.E. Mark. The mechanism of vesicle fusion as revealed by molecular dynamics simulations. JACS, 125:11144-11145, 2003.
  • [6] M. Louhivuori, H.J. Risselada, E. van der Giessen, S.J. Marrink. Release of content through mechano-sensitive gates in pressurized liposomes. PNAS, 107:19856-19860, 2010. open access
  • [7] C.Y Leung, L.C. Palmer, B.F. Qiao, S. Kewalramani, R. Sknepnek, C.J. Newcomb, M.A. Greenfield, G. Vernizzi, S.I. Stupp, M.J. Bedzyk, M. Olvera de la Cruz. Molecular Crystallization Controlled by pH Regulates Mesoscopic Membrane Morphology. ACS Nano, Just Accepted Manuscript, 2012. DOI: 10.1021/nn304321w.