Multi- to Unilamellar Transitions in Catanionic Vesicles
Multi- to Unilamellar Transitions in Catanionic Vesicles
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DOI：
10.1021/jp100437v
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发表时间：
2010-06-24
影响因子：
3.3
通讯作者：
Spinozzi, Francesco
中科院分区：
文献类型：
--
作者：
Andreozzi, Patrizia;Funari, Sergio S.;Spinozzi, Francesco
十二烷基硫酸钠（SDS）和十六烷基三甲基溴化铵（CTAB）分散在水溶液中形成阴阳离子囊泡。取决于组成，这样的囊泡显示不同的净电荷，稳定性和相互作用能力，表明阴阳离子系统可能在基因治疗和药物递送技术中具有强烈的影响。为了揭示组成，净电荷，对温度变化的敏感性，囊泡大小和内部结构之间的相互作用，在不同的SDS/CTAB摩尔比制备的阴阳离子囊泡进行了一系列的实验。动态光散射，小角度X射线散射，和zeta电位实验允许一个在纳米尺度上表征一个意想不到的关键现象。在加热时，囊泡的大小增加，但在临界温度下，已经观察到囊泡大小突然减小，以及从多到单层状态的过渡。临界温度通常取决于SDS/CTAB摩尔比。加热后获得的单层状态可保持数周。这些现象表明一种新的方法来生产稳定的单层囊泡与可调的大小和电荷。
Sodium dodecylsulfate (SDS) and cetyltrimethylammonium bromide (CTAB) dispersed in aqueous solution form catanionic vesicles. Depending on composition, such vesicles show different net charge, stability, and interaction capability, indicative of the strong impact that catanionic systems may have in gene therapy and drug delivery technologies. To reveal the interplay among composition, net charge, sensitivity to temperature changes, vesicle size, and inner structure, a series of experiments on catanionic vesicles prepared at different SDS/CTAB mole ratios was performed. Dynamic light scattering, small-angle X-ray scattering, and zeta-potential experiments allow one to characterize an unexpected critical phenomenon at the nanoscale level. On heating, vesicles increase in size, but at a critical temperature an abrupt vesicle size reduction has been observed, together with a transition from multi- to a unilamellar state. The critical temperature regularly depends on the SDS/CTAB mole ratio. The unilamellar state obtained upon heating is retained for weeks. These phenomena suggest a new way to produce stable unilamellar vesicles with tunable size and charge.