Thermally-Induced Order-Order Transition of DNA-Cationic Surfactant Complexes
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- 作者：Wei-Long Hsu ; Yen-Cheng Li ; Hsin-Lung Chen ; Willisa Liou ; U-Ser Jeng ; Hsien-Kuang Lin ; Wen-Liang Liu ; Chain-Shu Hsu
- 刊名：Langmuir
- 出版年：2006
- 出版时间：August 29, 2006
- 年：2006
- 卷：22
- 期：18
- 页码：7521 - 7527
- 全文大小：313K
- 年卷期：v.22,no.18(August 29, 2006)
- ISSN：1520-5827
文摘
Polyanionic DNA interacts with cationic amphiphiles to form electrostatic complexes exhibiting rich self-assembledstructures. This type of complex has been considered as a nonviral carrier in gene therapy and as a template fornanostructure construction. Here we report a thermally-induced phase transition of the complexes of DNA with themixtures of a cationic surfactant, dodecyltrimethyl bromide (DTAB), and a neutral lipid, dioleoylphosphatidylethanolamine (DOPE), in fully hydrated state. An order-order transition between a multilamellar (
) phase and aninverted hexagonal (
) phase was found to occur with the transition temperature adjustable by the DTAB-to-DNAbase pair molar ratio (x) and DOPE-to-DTAB molar ratio (m). The stability of the 
phase was enhanced at lowerm and x, as the 
-to-
transition temperature increased with the decreases of these two parameters. The suppressionof 
-to-
transition at lower x was attributed to the lower entropic gain from the counterion release due to thepresence of uncomplexed DNA in the bulk solution.
) phase and aninverted hexagonal () phase was found to occur with the transition temperature adjustable by the DTAB-to-DNAbase pair molar ratio (x) and DOPE-to-DTAB molar ratio (m). The stability of the phase was enhanced at lowerm and x, as the -to- transition temperature increased with the decreases of these two parameters. The suppressionof -to- transition at lower x was attributed to the lower entropic gain from the counterion release due to thepresence of uncomplexed DNA in the bulk solution.