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粗粒化方法研究囊泡在多层聚电解质衬底上的破裂机理
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摘要
以多层聚电解质为衬底,通过囊泡(可以连接功能性蛋白)吸附、扩散制备的磷脂双层在模拟细胞膜方面有很大的优势,但是囊泡是如何破裂形成磷脂双层的不是很清楚。在这篇文章中,我们借助粗粒化分子动力学模拟方法~1研究了囊泡在多层壳聚糖/藻朊酸盐衬底上经过吸附、变形、破裂和扩散,最终形成磷脂双层的过程。我们发现:在离子强度适宜的聚合物衬底上,囊泡一旦吸附就会完全破裂,并且形成了有序度很好的磷脂双层。如图1所示,破裂机理类似于"降落伞"模型~2,即在囊泡与聚合物衬底接触的外边缘处形成若干小孔,通过这些小孔,囊泡内层的磷脂头朝下,向下扩散构成了磷脂双层的下层,囊泡外层的绝大多数磷脂头朝上,向外扩散构成了磷脂双层的上层。而且我们的模拟结果也清晰地表明了,在此衬底上制备的磷脂双层不仅具有很好的对称性,而且它的横向扩散系数与自由双层保持在同一个数量级上。
Polyelectrolyte multilayers(PEMs)-supported lipid bilayers(SLBs) obtained via vesicle adsorption and spreading connecting with functional proteins are popular models to mimic cell membranes. However, the exact mechanism is not fully elucidated. In this study, we employ coarse-grained molecular dynamics simulations to investigate the pathways by which vesicles upon deposition undergo spreading on PEMs-cushioned substrates consisting of positive Chitosan(CHI) / negative Alginate(ALG) multilayers. We find that an isolated vesicle tends to be completely disintegrated upon deposition and form a well ordered lipid bilayer at appropriate polymer ionic strength, resembling a "parachute" model: The absorption induces multiple pores formation at the outer edge of the bottom of the vesicle. Moreover, our simulation results clearly indicate the created SLBs on the PEMs support well preserve the lateral mobility and symmetric density profile of the phospholipids as of the free-standing bilayer.
引文
[1]Arnarez,C.;Uusitalo,J.J.;Masman,M.F.;lfsson,H.I.JCTC 2015,11:260.
    [2]Fuhrma s,M.;Mu?ller,M.Langmuir 2013,29:4335.

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