自發曲率、金屬離子吸附以及微脂體膜融合效率三者間之相關性探討

The Correlation among Spontaneous Curvature, Metal Ions Binding and Membrane Fusion of Liposomes

樊子安(Zih-an Fan)

指導教授 ： 陳儀帆

國立中央大學/工學院/化學工程與材料工程學系/碩士(2015年)

摘要

本研究旨在探討monolayer spontaneous curvature、金屬離子binding以及膜融合三者之間的關係。膜融合是在細胞的生命活動中一個重要且常見的過程，例如：包有神經傳導物質的囊泡藉由鈣離子觸發，與神經細胞的細胞膜進行膜融合並將神經傳導釋出。我們將dioleoyl phosphatidylethanolamine/dioleoyl phosphatidylcholine/4 mol% dioleoyl phosphatidic acid脂質混合物製備成可以模擬生物系統的unilamellar vesicle以及為了量測spontaneous curvature的dispersion兩種樣品。影響膜融合的因素包括monolayer spontaneous curvature以及金屬離子binding。Monolayer spontaneous curvature（C0）是一種彈性性質，它量化脂質分子形成lamellar phase或是nonlamellar phase的趨勢，而nonlamellar phase的形成則被認為是在膜融合中一個重要的過程。從我們的實驗結果發現，膜融合的效率隨著spontaneous curvature的增加而增加。當金屬離子binding在脂質膜時會影響脂質膜的穩定性以及性質。從我們的實驗結果發現，spontaneous curvature和金屬離子binding皆會使脂質膜的厚度增加，但是，膜厚的變化並不足以影響膜融合；DOPE與DOPC頭基的不同造成金屬離子binding對spontaneous curvature的影響程度不同。我們也發現，金屬離子binding影響intra-monolayer與inter-monolayer，進而改變spontaneous curvature與脂質的自組裝結構，最後影響膜融合的效率。

關鍵字

自發曲率 ； 金屬離子結合 ； 微脂體 ； 膜融合

並列摘要

In the present work, we investigate the correlation among spontaneous curvature, metal ions binding and membrane fusion of liposomes. Membrane fusion is an important process of many cellular events, such as neuronal signaling. In order to simulate the biological system, we use DOPE/DOPC/4 mol% DOPA lipid mixture to prepare the unilamellar vesicle. We also prepare lipid dispersion for the measurement of monolayer spontaneous curvature. There are many factors that can affect membrane fusion, including the monolayer spontaneous curvature and metal ions binding. Monolayer spontaneous curvature (C0) quantifies the tendency of forming lamellar phase or nonlamellar phase. Forming nonlamellar structure is considered to be associated with membrane fusion. When the spontaneous curvature become more negative, membrane fusion efficiency will increase. The binding of metal ions to biological membranes affects the stability and the properties of lipid bilayer, is associated with membrane fusion. Both spontaneous curvature and metal ions binding induce lipid membrane thicker. However, the difference of membrane thickness is too small to affect membrane fusion. The influence of metal ions binding to DOPE and DOPC spontaneous curvature is different, due to the difference of lipid headgroup composition. The binding of metal ions to lipid membrane affects lipid intra-monolayer and lipid inter-monolayer, changing the spontaneous curvature and liposome structure, and then, membrane fusion efficiency will be impacted.

並列關鍵字

spontaneous curvature ； metal ions binding ； liposome ； membrane fusion

參考文獻

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