Shimokawa Naofumi, Komura Shigeyuki, Andelman David
Institute of Industrial Science, University of Tokyo, Tokyo 153-8505, Japan.
Phys Rev E Stat Nonlin Soft Matter Phys. 2011 Sep;84(3 Pt 1):031919. doi: 10.1103/PhysRevE.84.031919. Epub 2011 Sep 19.
We consider the phase separation in an asymmetrically charged lipid bilayer membrane consisting of neutral and negatively charged lipids that are in contact with in and out ionic solutions having different ionic strengths. The two asymmetric leaflets are coupled through electrostatic interactions. Based on a free-energy approach, the critical point and phase diagrams are calculated for different ionic strengths of the two solutions and coupling parameter. An increase of the coupling constant or asymmetry in the salt concentration between the in and out solutions yields a higher phase-separation temperature because of electrostatic interactions. As a consequence, the phase-coexistence region increases for strong screening (small Debye length). Finally, possible three-phase coexistence regions in the phase diagram are predicted.
我们考虑由中性和带负电荷的脂质组成的不对称带电脂质双层膜中的相分离，该膜与具有不同离子强度的内外离子溶液接触。两个不对称的叶层通过静电相互作用耦合。基于自由能方法，计算了两种溶液不同离子强度和耦合参数下的临界点和相图。由于静电相互作用，耦合常数的增加或内外溶液盐浓度的不对称会产生更高的相分离温度。因此，对于强屏蔽（小德拜长度），相共存区域会增加。最后，预测了相图中可能的三相共存区域。
