NEARLY SPHERICAL VESICLE SHAPES CALCULATED BY USE OF SPHERICAL-HARMONICS - AXISYMMETRICAL AND NONAXISYMMETRIC SHAPES AND THEIR STABILITY
NEARLY SPHERICAL VESICLE SHAPES CALCULATED BY USE OF SPHERICAL-HARMONICS - AXISYMMETRICAL AND NONAXISYMMETRIC SHAPES AND THEIR STABILITY
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DOI：
10.1051/jp2:1992188
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发表时间：
1992-05-01
期刊：
影响因子：
--
通讯作者：
ZEKS, B
中科院分区：
文献类型：
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作者：
HEINRICH, V;BRUMEN, M;ZEKS, B
提出了一种确定磷脂囊泡近球形的理论方法。该方法是一般的，因为它不依赖于任何对称限制。假设平衡形状对应于膜面积、囊泡体积和磷脂双分子层两小叶面积之差恒定值下膜弯曲弹性能的最小值。将弯曲能和约束扩展到球面偏差的四阶项，并在随后的计算中包含所有三阶项。偏差表示为一系列球面谐波。结果表明，通过检测弯曲能量二阶导数矩阵相对于球谐波展开独立幅值的特征值，可以检验解的稳定性。将该方法应用于轴对称和非轴对称形状的计算，讨论了不同近似对计算结果的影响。结果表明，在小叶面积差异的变化中，稳定扁圆形和稳定长条形是连续地相互转化的。
A theoretical approach to determine nearly spherical shapes of phospholipid vesicles is developed. The method is general in the sense that it does not depend on any symmetry restrictions. Equilibrium shapes are assumed to correspond to the minimum of the membrane bending elastic energy at constant values of the membrane area, the vesicle volume and the difference of areas of the two leaflets of the phospholipid bilayer. The bending energy and the constraints are expanded up to fourth order terms in the deviation from a sphere, and in the subsequent calculations all terms up to the third order are included. The deviation is expressed as a series of spherical harmonics. It is shown that the stability of the solutions can be tested by inspecting the eigenvalues of the matrix of second derivatives of the bending energy with respect to independent amplitudes of spherical harmonics expansion. The method is applied to the calculation of axisymmetric and nonaxisymmetric shapes, and the influences of different approximations are discussed. It is shown that at variations of the leaflet area difference stable oblate and stable prolate shapes are transformed into each other in a continuous manner.