caa a22 4500 467893055 CHVBK 20180406152754.0 cr unu---uuuuu 170328e20061101xx s 000 0 eng 10.1007/s10955-006-9051-9 doi (NATIONALLICENCE)springer-10.1007/s10955-006-9051-9 Quadrupolar ordering of phospholipid molecules in narrow necks of phospholipid vesicles [Elektronische Daten] [Veronika Kralj-Iglič, Blaž Babnik, Dorit Gauger, Sylvio May, Aleš Iglič] Shapes of phospholipid vesicles that involve narrow neck(s) were studied theoretically. It is taken into account that phospholipid molecules are intrinsically anisotropic with respect to the membrane normal and that they exhibit quadrupolar orientational ordering according to the difference between the local principal membrane curvatures. Direct interactions between oriented molecules were considered within a linear approximation of the energy coupling with the deviatoric field. The equilibrium shapes of axisymmetric closed vesicles were studied by minimization of the free energy of the phospholipid bilayer membrane under relevant geometrical constraints. The variational problem was stated by a system of Euler-Lagrange differential equations that revealed a singularity in the derivative of the meridian curvature at points where the effect of the orientational ordering exactly counterbalances the effect of the isotropic bending. The system of Euler-Lagrange differential equations was solved numerically to yield consistently related equilibrium orientational distribution of the phospholipid molecules and vesicle shape. According to our estimation of the model constants the formation of the neck is promoted if direct interactions between the oriented molecules are taken into account. It was shown that the energy of the equilibrium shapes is considerably affected by the quadrupolar ordering of phospholipid molecules. Springer Science+Business Media, Inc., 2006 phospholipid vesicle shape nationallicence neck nationallicence deviatoric bending nationallicence curvature singularity nationallicence quadrupolar ordering nationallicence Kralj-Iglič Veronika Institute of Biophysics, Faculty of Medicine, University of Ljubljana, Lipičeva 2, SI-1000, Ljubljana, Slovenia aut Babnik Blaž Laboratory of Physics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, SI-1000, Ljubljana, Slovenia aut Gauger Dorit Research group "Lipid Membranes,”, Friedrich-Schiller University, Neugasse 25, 07745, Jena, Germany aut May Sylvio Research group "Lipid Membranes,”, Friedrich-Schiller University, Neugasse 25, 07745, Jena, Germany aut Iglič Aleš Laboratory of Physics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, SI-1000, Ljubljana, Slovenia aut Journal of Statistical Physics Kluwer Academic Publishers-Plenum Publishers; http://www.springer-ny.com 125/3(2006-11-01), 727-752 0022-4715 125:3<727 2006 125 10955 https://doi.org/10.1007/s10955-006-9051-9 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10955-006-9051-9 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kralj-Iglič Veronika Institute of Biophysics, Faculty of Medicine, University of Ljubljana, Lipičeva 2, SI-1000, Ljubljana, Slovenia aut NATIONALLICENCE 700 1- Babnik Blaž Laboratory of Physics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, SI-1000, Ljubljana, Slovenia aut NATIONALLICENCE 700 1- Gauger Dorit Research group "Lipid Membranes,”, Friedrich-Schiller University, Neugasse 25, 07745, Jena, Germany aut NATIONALLICENCE 700 1- May Sylvio Research group "Lipid Membranes,”, Friedrich-Schiller University, Neugasse 25, 07745, Jena, Germany aut NATIONALLICENCE 700 1- Iglič Aleš Laboratory of Physics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, SI-1000, Ljubljana, Slovenia aut NATIONALLICENCE 773 0- Journal of Statistical Physics Kluwer Academic Publishers-Plenum Publishers; http://www.springer-ny.com 125/3(2006-11-01), 727-752 0022-4715 125:3<727 2006 125 10955 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer