本研究利用等莫耳比例混合的陽離子型界面活性劑hexadecyltrimethylammonium bromide (HTMAB)與陰離子型界面活性劑sodium dodecylsulfate (SDS)生成離子對雙親分子(ion pair amphiphile, IPA) hexadecyltrimethylammonium-dodecylsulfate (HTMA-DS)。然後以強制性製程由HTMA-DS和雙十四碳鏈陽離子型界面活性劑ditetradecyldimethylammonium bromide (DTDAB)製備出帶正電的陰陽離子液胞。為了提升液胞的基因轉染效率，先探討鈣離子的存在對陰陽離子液胞物化特性的影響，再探討陰陽離子液胞與DNA混合所形成之複合物的物化特性。所使用的分析方法包括粒徑/界面電位分析法、穿透式電子顯微鏡法、傅立葉紅外光譜法、Langmuir單分子層行為分析法、DNA電泳法及螢光偏極化法。
結果顯示鈣離子的加入會改變分散液中液胞間的靜電斥力，而降低液胞的物理穩定性。然而透過膽固醇的添加，可避免因鈣離子所造成的液胞物理穩定性下降。進一步分析顯示，液胞的物理穩定性除了與液胞間的靜電斥力有關外，膽固醇於液胞雙層膜中可增加液胞組成分子的運動性，而能調整分子的排列達到促進液胞物理穩定性的效果。
陰陽離子液胞與DNA的複合行為明顯與混合比例有關。由DNA電泳實驗可發現，當液胞與DNA的混合比例為30:1時，DNA可與液胞完全結合形成複合物。降低混合比例可使複合物帶負電，反之則獲得帶正電的複合物。此外，液胞分散液經稀釋後會降低液胞的物理穩定性。藉由螢光偏極化法的分析，可發現當液胞分散液稀釋後，液胞雙層膜中分子的運動性會隨著時間逐漸減少，使得液胞的物理穩定性降低。這可能是因為稀釋使得HTMA+由液胞溶出於分散相中的數目增加，而減低了液胞表面的電荷密度。
高濃度的液胞與DNA混合形成的帶正電複合物，其物理穩定性會因為複合物之間的靜電斥力不足而產生聚集現象。在低混合比例下所形成的液胞/DNA複合物中，則因液胞分散液經稀釋後所造成雙層膜內分子排列特性的改變，而導致複合物物理穩定性的下降。
利用3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide（MTT）分析法評估HTMA-DS/DTDAB與HTMA-DS/DTDAB/膽固醇混合系統所形成的陰陽離子液胞對HS68細胞的毒性，結果顯示與商用之基因轉染載體有類似的結果。進一步觀察綠色螢光蛋白基因於轉染後在細胞內的表現量，顯示以HTMA-DS/DTDAB混合系統所形成之陰陽離子液胞系統有做為基因轉染載體的潛力。分別改以雙十六碳鏈的dihexadecyldimethylammonium bromide （DHDAB）與雙十八碳鏈的dioctadecyldimethylammonium bromide（DODAB）取代雙十四碳鏈的DTDAB所製備出之陰陽離子液胞，並評估其對HEK細胞的毒性，發現含DHDAB的液胞有較低的細胞毒性，且有較佳的轉染效率。

In this study, positively charged catanionic vesicles were fabricated from hexadecyltrimethylammonium-dodecylsulfate (HTMA-DS) with the addition of a double-chained cationic surfactant, dimethyldimyristylammonium bromide (DTDAB), by using a forced formation approach. The effects of Ca2+ on physical characteristics of the catanionic vesicles were investigated. Furthermore, physical characteristics of the catanionic vesicle/DNA complexes were explored. The results implied that the physical stability of the vesicles was not only related to the inter-vesicle electrostatic repulsion, but also to the molecular packing/interaction in the vesicular bilayers. The molecular fluidity of the vesicular bilayer could be enhanced with the additon of cholesterol, and the molecular packing became less ordered. The fluorescence polarization analysis suggested that the molecular fluidity of the vesicular bilayers was decreased with time when the vesicle dispersion was diluted, resulting in reduced physical stability. It was proposed that the dissolution of HTMA+ from the vesicles was enhanced by the dilution operation. Moreover, the vesicle surfaces were less charged and the vesicular bilayers became rigid.

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