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Title: | 利用膽固醇調控磷脂質的自組裝奈米有序微結構 Control over the self-assembled ordered nanostructures of phospholipids by incorporation of cholesterol |
Authors: | Chia-Chun Lee 李家淳 |
Advisor: | 童世煌 |
Keyword: | 磷脂質,自組裝,薄膜,膽固醇,小尺寸結構, phospholipids,self-assembly,thin film,cholesterol,small-scale structure, |
Publication Year : | 2017 |
Degree: | 碩士 |
Abstract: | 膽固醇與磷脂質間的交互作用在水相系統中已有廣泛的研究,已知膽固醇的存在可以抑制烴鏈的運動,具有穩定細胞膜的功用。在本次研究中,不同於在水相系統中的自組裝行為,我們探討在薄膜或塊材中膽固醇對其自組裝結構的影響。我們選擇了在碳鏈中含有不同雙鍵數目的Soy PC、DOPC、Egg PC和DPPC做比較。
我們利用原子力顯微鏡與X光散射技術來分析薄膜中的結構並且發現分子間堆疊的好壞與磷脂中雙鍵數目的多寡有很大的關係,我們發現透過改變膽固醇添加的比例,可以誘導僅含有單個雙鍵的Egg PC分子在薄膜中產生球狀、柱狀以及層狀等微結構;在含有多個雙鍵的Soy PC與DOPC中則產生球狀及柱狀結構;而沒有雙鍵的DPPC則僅能形成層狀結構的堆疊。我們也使用傅里葉紅外線光譜儀來研究卵磷脂和膽固醇之間的相互作用,發現膽固醇會與磷脂分子中的磷酸根產生氫鍵鍵結,並利用示差掃描熱分析儀得知膽固醇的嵌入會對磷脂分子的熱性質有很大的影響,證實膽固醇與磷脂分子間確實有作用力的生成。 由膽固醇誘導所形成的球狀、柱狀以及層狀結構僅約4奈米,相較於嵌段共聚物的微相分離結構要小得多,應用於奈米結構的製備上將更具優勢。 The interactions between cholesterol and phospholipids have been extensively studied in the aqueous systems. It has been known that the presence of cholesterol can stabilize the cell membrane by inhibiting the movement of hydrocarbon chains. In this study, instead of the self-assembly in aqueous solutions, we probed the impact of cholesterol on the ordered microphase separated structures between the hydrophilic headgroups and the hydrophobic tails of phospholipids in thin film and bulk state. Four phospholipids with varying number of double bonds on the hydrocarbon tails were investigated, including Soy PC, DOPC, Egg PC and DPPC. We utilized atomic force microscopy (AFM) and small-angle X-ray scattering techniques (SAXS and GISAXS) to analyze the structures of phospholipid/cholesterol mixtures and found the structures of the mixtures is highly dependent on the number of double bonds. By changing the fraction of cholesterol, Egg PC with one double bond can phase separate into a variety of regular structures, including spherical, cylindrical and lamellar microdomains, while Soy PC and DOPC with multiple double bonds form spheres and cylinders, and DPPC with no double bond forms lamellae only. We used Fourier transform infrared (FTIR) spectrometer to evidence that cholesterol inserts into phospholipids and form hydrogen bonding with the phosphate on the headgroup. The differential scanning calorimetry (DSC) measurements show that the incorporation of cholesterol into phospholipids significantly affects the thermal behaviors of phospholipids, confirming the interactions between cholesterol and the phospholipids. The domain sizes of the spheres, cylinders, and lamellae formed by the phospholipid/cholesterol mixtures are less than 4 nm, so small that typical block copolymers are unable to reach. The systems developed in this work could be potential for applications such as new templates for fabrication of nanomaterials. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/67690 |
DOI: | 10.6342/NTU201702055 |
Fulltext Rights: | 有償授權 |
Appears in Collections: | 高分子科學與工程學研究所 |
Files in This Item:
File | Size | Format | |
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ntu-106-1.pdf Restricted Access | 4.7 MB | Adobe PDF |
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