none;The effects of composition and thermal history on the properties of supported lipid bilayers

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/54152

Title:	none;The effects of composition and thermal history on the properties of supported lipid bilayers
Authors:	林宗毅;Lin,Chung-yi
Contributors:	生物物理研究所
Keywords:	原子力顯微鏡;雲母片效應;DPPC;POPC;SLBs;基板支撐的脂質雙層;細胞膜模型;fluidus temperature;fluidus temperature;supported lipid bilayers;SLBs;POPC;DPPC;model membrane;AFM;mica effect
Date:	2012-07-27
Issue Date:	2012-09-11 18:37:44 (UTC+8)
Publisher:	國立中央大學
Abstract:	由基板支撐的脂質雙層經常被用在生物細胞膜的基礎研究上，除此之外也常常被當作為模型在研究生物探測器或是用在細胞膜融合蛋白質與細胞受器的研究上。但對於基板支撐的脂質雙層的物理特性並非完全了解。我們利用原子力顯微鏡 (AFM) 研究在雲母基板上的脂質雙層 (mica-supported lipid bilayers)，而在本研究中脂質雙層主要由POPC和DPPC組成。首先我們借著改變降溫速率來探討降溫過程對脂質雙層的表面形態影響，當降溫速率增加時會造成脂質雙層產生較多且面積較小的凝膠相區塊。在研究脂質雙層的AFM影像與時間的關係中我們觀察到脂質雙層在到達特定溫度後，約需130鐘以達到平衡。而我們也研究脂質雙層的相變，從AFM影像與溫度的關係得知，在廣泛的溫度區間內皆可觀察到凝膠相與液晶相的共存，並且在實驗中只有觀察到一次從凝膠相到液晶相的相變。在POPC 和DPPC 構成的脂質雙層內沒有觀察到脂質雙層的非耦合現象。Support Lipid bilayers are important in the fundamental studies of biological membrane; they could be as a model for incorporation of proteins and receptors or be used for investigation of biosensor. However, not of all physical prosperities are known clearly. We studied the physical properties of mica-supported lipid bilayers using atomic force microscopy (AFM). Our lipid bilayers consist of a binary mixture of POPC and DPPC. To study the effect of thermal process on the supported bilayer, AFM images of supported lipid bilayers were acquired as a function of cooling rate. We found that fast cooling rate produces a large number of smaller gel domains in the bilayer. To learn the equilibrium property of the supported bilayer, AFM images were also studied as a function of time. Our data shows that it takes about ~130 minutes for the bilayer to reach equilibrium after the temperature of the bilayer is raised to 25°C. To investigate the phase behavior of supported bilayers, AFM images were studied as a function of temperature. Coexistence of higher (or gel) and lower (or liquid) domains was found in a wide temperature range and only one gel-to-liquid phase transition was observed in the temperature range studied. Decoupling of the lipid bilayer is not observed in POPC/DPPC.
Appears in Collections:	[Graduate Institute of Biophysics] Electronic Thesis & Dissertation

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