Thermally-induced order-order transition of DNA-cationic surfactant complexes.
Polyanionic DNA interacts with cationic amphiphiles to form electrostatic complexes exhibiting rich self-assembled structures. This type of complex has been considered as a nonviral carrier in gene therapy and as a template for nanostructure construction. Here we report a thermally-induced phase transition of the complexes of DNA with the mixtures of a cationic surfactant, dodecyltrimethyl bromide (DTAB), and a neutral lipid, dioleoylphosphatidylethanolamine (DOPE), in fully hydrated state. An order-order transition between a multilamellar (L(c)alpha) phase and an inverted hexagonal (H(c)II) phase was found to occur with the transition temperature adjustable by the DTAB-to-DNA base pair molar ratio (x) and DOPE-to-DTAB molar ratio (m). The stability of the L(c)alpha phase was enhanced at lower m and x, as the L(c)alpha-to-H(c)II transition temperature increased with the decreases of these two parameters. The suppression of -to- transition at lower x was attributed to the lower entropic gain from the counterion release due to the presence of uncomplexed DNA in the bulk solution.
Hsu
Wei-Long
WL
Department of Chemical Engineering, National Tsing Hua University, Hsin-Chu 30013, Taiwan.
Li
Yen-Cheng
YC
Chen
Hsin-Lung
HL
Liou
Willisa
W
Jeng
U-Ser
US
Lin
Hsien-Kuang
HK
Liu
Wen-Liang
WL
Hsu
Chain-Shu
CS
D002412:Cations / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D010714:Phosphatidylethanolamines / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D012996:Solutions; D013501:Surface-Active Agents / Q000737:chemistry*; D013696:Temperature
C410262:1,2-dioleoyl-glycero-3-phosphatidyl ethanolamine; D002412:Cations; D010714:Phosphatidylethanolamines; D000644:Quaternary Ammonium Compounds; D012996:Solutions; D013501:Surface-Active Agents; C013912:decyltrimethylammonium; D004247:DNA