An AFM Study on Supported Lipid Bilayers with and without Sterol

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/59198

Title:	An AFM Study on Supported Lipid Bilayers with and without Sterol
Authors:	張簡維軍;Wei-Chun,Chang-Chien
Contributors:	物理學系
Keywords:	DOPC;DPPC;人造細胞膜;原子力顯微鏡;基板支撐的脂質雙層;麥角固醇;AFM;DOPC;DPPC;ergosterol;model membrane;supported lipid bilayers
Date:	2013-01-29
Issue Date:	2013-03-25 16:06:12 (UTC+8)
Publisher:	國立中央大學
Abstract:	在這篇論文中，我們利用原子力顯微鏡 (AFM) 來探討以雲母片為基底的脂質雙層(SLBs)在液態環境下的表面形貌。首先我們利用研究由小脂質單層囊泡 (SUV) 所得到的脂質雙層 1:1 DOPC/DPPC來最佳化樣品準備過程的實驗參數。其次，為了探討固醇對脂質雙層的影響，我們研究由小脂質單層囊泡 (SUV) 所得到的脂質雙層 1:1 POPC/DPPC 和 1:1 (POPC/DPPC) + 33mol% erg 表面形貌。為了了解溫度對脂質雙層的影響，我們也探討了在不同溫度下脂質雙層 1:1 POPC/DPPC 和 1:1 (POPC/DPPC) + 33mol% erg AFM影像。含有固醇和不含固醇的樣品表面形貌非常不同。我們觀察到在這兩種樣品的AFM影像中，都有兩種不同厚度的脂質區塊。實驗結果顯示不含固醇樣品的單一相溫度 (one-phase temperature) 高於含有固醇的樣品。此外隨著溫度上升到單一相溫度，含有固醇和不含固醇的脂質雙層有不同的熔化行為。藉由比較AFM和NMR 實驗數據，我們推測在不含固醇的樣品中，較厚的脂質區塊處於凝膠態 (gel phase)。而含有固醇的樣品中，較厚的脂質區塊處於液晶態 (liquid ordered phase)。In this thesis, we investigate the morphology of supported lipid bilayers (SLBs) on mica using atomic force microscopy (AFM) in liquid environment. To find the optimal conditions for the preparation of SLBs, the properties of 1:1 DOPC/DPPC prepared from small unilamellar vesicle (SUV) were studied. To investigate the effect of sterol on SLBs, the morphologies of 1:1 POPC/DPPC and 1:1 (POPC/DPPC) + 33 mol% erg prepared from SUV were studied. To investigate effect of temperature on SLBs, AFM images of 1:1 POPC/DPPC and 1:1 (POPC/DPPC) + 33mol% erg were also studied as a function of temperature. The morphologies of SLBs with and without sterol are very different. Higher and lower domains were observed in AFM images of both erg-free and erg-containing SLBs. The one-phase temperature in erg-free SLBs is higher than erg-containing SLBs. The “melting” behaviors of erg-free and erg-containing SLBs are different when the temperature is raised. By comparing AFM and NMR data, we suggest the higher domains in erg-free and erg-containing SLBs are in the gel and liquid ordered phases, respectively.
Appears in Collections:	[Graduate Institute of Physics] Electronic Thesis & Dissertation

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