Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/50143
標題: Impurity Mediated Membrane Transiton Perturbation
微量分子參雜誘發脂質分子雙層膜像變行為調制之研究
作者: 施明智
關鍵字: 其他(理)
基礎研究
摘要: Phospholipids make up the backbone for cell membranes and the gel-fluid phase transition is considered as a crucial factor in regulating the activities of membrane functions. A popular approach to investigate the structure, dynamics and function of membrane related behaviour is based on fluorescence microscopy. Recent researches indicate that one can gauge the transition properties of membranes via different probe type selection. Our recent preliminary experiments on pure DPPC GUVs also exhibit fluorescent dyes dependent transition behaviours. In GUVs incorporated with NBD-PC dye, GUV shrink at phase transition; while, DPPC GUVs visualized with Rhodamine-B dye burst before transition can be completed. Preferential localization of NDB probe results in enhancing anomalous permeability is proposed to explain the observed phenomena. In the other hand, a possible complex forming model is hypothesized to account for the different behaviour found in RB contained lipid bilayers. These two models suggest the important factor behind the impurity dependent transition properties modulation is entropic origin instead of energetic origin. This is a novel concept and it could be of great important in understand membrane function and fluorescence microscopy application. This proposal aims for verifying these two hypothetical models and investigate their physical mechanism.
脂質分子為細胞膜構成之主要成分,而其所擁有的膠體態至液體態的相變行為被認為是調制細胞膜行為與功能的重要機制。目前最廣泛應與於探討細胞膜結構、性質與動態行為的技術為螢光顯微術。螢光分子的參雜為該顯微術之基本必要條件,然而近期中許多研究顯示該參雜行為會導致脂質膜系統相變行為之變異。更重要的是,此誘發變異行為與螢光分子種類相關。我們的近期實驗亦發現,使用NBD或RB螢光標定分子觀測微脂粒系統,其相變特徵呈現不同反應。含NBD螢光標定分子系統的膠體態至液體態相變溫度會降低,且其宏觀行為為微脂粒尺寸大小會縮減。RB系統的相變溫度反向的提升,而其主要宏觀相變行為為微脂粒的瞬間破裂。未解釋此差異性的相變特質調制現象,我們大膽的假設兩種不同之模型。我們假設NBD分子於脂質膜中的分佈有選擇性,此偏好行為加巨兩相結構間entropy的差距而導致相變溫度的下降,也加劇了相變誘發通透率上升形成微脂粒縮小的現象。相對的,RB分子因擁有巨大親水團可能形成與脂質分子形成複合體的結構,而此行為可能導致導致相變溫度上升與微脂粒破裂的現象。若此二假設成立,則將隱含entropy主導相變行為調制新觀念的建立。此概念將對細胞膜性質的認識與螢光顯微術的應用有莫大助益。此計畫的主軸將著重於此二模型之確立與該模型之物理基礎探討。
URI: http://hdl.handle.net/11455/50143
其他識別: NSC99-2112-M005-003-MY2
文章連結: http://grbsearch.stpi.narl.org.tw/GRB/result.jsp?id=2131187&plan_no=NSC99-2112-M005-003-MY2&plan_year=99&projkey=PA9907-2570&target=plan&highStr=*&check=0&pnchDesc=%E5%BE%AE%E9%87%8F%E5%88%86%E5%AD%90%E5%8F%83%E9%9B%9C%E8%AA%98%E7%99%BC%E8%84%82%E8%B3%AA%E5%88%86%E5%AD%90%E9%9B%99%E5%B1%A4%E8%86%9C%E5%83%8F%E8%AE%8A%E8%A1%8C%E7%82%BA%E8%AA%BF%E5%88%B6%E4%B9%8B%E7%A0%94%E7%A9%B6
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