Lee Jung, Chang Chien-Hsiang
Department of Chemical Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 701, Taiwan.
Department of Chemical Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 701, Taiwan.
Colloids Surf B Biointerfaces. 2014 Sep 1;121:171-7. doi: 10.1016/j.colsurfb.2014.06.005. Epub 2014 Jun 7.
Physical stability control of vesicle/DNA complexes is a key issue for the development of catanionic vesicles composed of ion pair amphiphile (IPA) as DNA carriers. In this work, physical stability characteristics of the complexes of DNA with positively charged catanionic vesicles composed of an IPA and a double-chain cationic surfactant, dihexadecyldimethylammonium bromide (DHDAB), were explored. It was found that in water, the mixed IPA/DHDAB catanionic vesicles became stable when the mole fraction of DHDAB (xDHDAB) was increased up to 0.5. The improved physical stability of the vesicles with a high xDHDAB could be related to the enhanced electrostatic interaction between the vesicles. When the catanionic vesicles interacted with DNA, excellent physical stability was detected for the vesicle/DNA complexes especially with a high xDHDAB. However, this could not be fully explained by the electrostatic interaction effect, and the role of molecular packing within the vesicular bilayers was apparently important. The corresponding Langmuir monolayer study demonstrated that the molecular packing of mixed IPA/DHDAB layers became ordered with DNA association due to inhibited desorption of the positively charged moiety of the IPA. Moreover, the DNA association-induced improvement in the molecular packing of the mixed IPA/DHDAB layers became pronounced with increased xDHDAB. The results imply that one can fabricate catanionic vesicle/DNA complexes with excellent physical stability through the improved molecular packing in the IPA vesicular bilayers with DHDAB addition and DNA association.
囊泡/DNA复合物的物理稳定性控制是开发由离子对两亲物（IPA）作为DNA载体组成的阴阳离子囊泡的关键问题。在这项工作中，研究了DNA与由IPA和双链阳离子表面活性剂二己基二甲基溴化铵（DHDAB）组成的带正电阴阳离子囊泡复合物的物理稳定性特征。发现在水中，当DHDAB的摩尔分数（xDHDAB）增加到0.5时，混合的IPA/DHDAB阴阳离子囊泡变得稳定。具有高xDHDAB的囊泡物理稳定性的提高可能与囊泡之间增强的静电相互作用有关。当阴阳离子囊泡与DNA相互作用时，特别是对于具有高xDHDAB的囊泡/DNA复合物，检测到了优异的物理稳定性。然而，这不能完全用静电相互作用效应来解释，并且囊泡双层内分子堆积的作用显然很重要。相应的Langmuir单层研究表明，由于IPA带正电部分的解吸受到抑制，混合的IPA/DHDAB层的分子堆积随着DNA缔合而变得有序。此外，随着xDHDAB的增加，DNA缔合引起的混合IPA/DHDAB层分子堆积的改善变得更加明显。结果表明，通过在IPA囊泡双层中添加DHDAB并缔合DNA来改善分子堆积，可以制备具有优异物理稳定性的阴阳离子囊泡/DNA复合物。
