Boni L T, Minchey S R, Perkins W R, Ahl P L, Slater J L, Tate M W, Gruner S M, Janoff A S
Liposome Company, Inc., Princeton, NJ.
Biochim Biophys Acta. 1993 Mar 14;1146(2):247-57. doi: 10.1016/0005-2736(93)90363-5.
Ethanol causes biphasic melting behavior in saturated lecithins (Rowe (1983) Biochemistry 22, 3299-3305), a consequence of the formation of the stable interdigitated phase (Simon, S.A. and McIntosh, T.J. (1984) Biochim. Biophys. Acta 773, 169-172). The membrane systems studied to date have been large vesicle systems in which the membrane surface can be assumed to be locally planar. An immediate question arises as to whether surfaces of higher curvature interdigitate. To address this question we have prepared DPPC vesicles of varying diameters which we employed to determine the limiting size at which interdigitation occurs using ethanol as the inducer. We find that with decreasing vesicle size the concentration of ethanol necessary for the onset of interdigitation increases. Small isolated vesicles, at inducing concentrations of ethanol, do not stably interdigitate but rupture and coalesce into a viscous gel comprised of interdigitated lipid sheets. As discussed elsewhere (Ahl et al. (1992) Biophys. J. 243a) these sheets can be used as precursors for producing liposomes of large size and high internal volumes useful in drug delivery or modeling applications.
乙醇会导致饱和卵磷脂出现双相熔化行为（罗（1983年），《生物化学》22卷，3299 - 3305页），这是稳定的交叉排列相形成的结果（西蒙，S.A.和麦金托什，T.J.（1984年），《生物化学与生物物理学报》773卷，169 - 172页）。迄今为止所研究的膜系统都是大囊泡系统，在这种系统中可以假定膜表面是局部平面的。一个直接的问题是，具有更高曲率的表面是否会交叉排列。为了解决这个问题，我们制备了不同直径的二棕榈酰磷脂酰胆碱（DPPC）囊泡，并用乙醇作为诱导剂来确定发生交叉排列的极限尺寸。我们发现，随着囊泡尺寸减小，开始发生交叉排列所需的乙醇浓度会增加。在乙醇诱导浓度下，小的孤立囊泡不会稳定地交叉排列，而是会破裂并聚合成由交叉排列的脂质片组成的粘性凝胶。如在其他地方所讨论的（阿尔等人（1992年），《生物物理杂志》243a），这些脂质片可作为制备大尺寸、高内部体积脂质体的前体，这些脂质体在药物递送或建模应用中很有用。
