DOTAP/DOPE and DC-Chol/DOPE lipoplexes for gene delivery: zeta potential measurements and electron spin resonance spectra
DOTAP/DOPE and DC-Chol/DOPE lipoplexes for gene delivery: zeta potential measurements and electron spin resonance spectra
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DOI：
10.1016/j.bbamem.2004.04.003
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发表时间：
2004-07-01
影响因子：
3.4
通讯作者：
Martini, G
中科院分区：
文献类型：
--
作者：
Ciani, L;Ristori, S;Martini, G
非病毒载体是基因传递的一种重要选择。在这些载体中，阳离子脂质体由于能够与DNA片段(脂簇)形成稳定的络合物而被广泛研究。在本工作中，我们报道了用电子自旋共振(ESR)光谱和Zeta电位测量阳离子脂质体及其与寡核苷酸的络合物的表征。脂质体由两性离子脂类、药物和阳离子脂类，DOTAP或DC-Chol制成。寡核苷酸是20碱基的单链PolyA、20碱基的单链Polyt和相应的双链DSAT。Zeta电位随寡核苷酸/脂(+)比例的变化呈S形滴定曲线。在阳离子脂头和寡核苷酸上的磷酸基团之间进行电荷补偿时，发生了明确的表面电位变化。反转点取决于正在研究的特定系统。适当定制的自旋探针的ESR光谱也监测了双分子膜的性质和DNA片段的掺入所发生的变化。对于所研究的所有体系，ESR谱显示在脂络合物形成后没有发生重大变化，分子堆积基本保持不变。Zeta电位和ESR测量都支持脂丛的外部堆积模式。(C)2004爱思唯尔B.V.保留所有权利。
Non-viral vectors represent an important alternative in gene delivery. Among these vectors, cationic liposomes are widely studied, because of their ability to form stable complexes with DNA fragments (lipoplexes). In the present work, we report on the characterization by electron spin resonance (ESR) spectroscopy and zeta potential measurements of cationic liposomes and of their complexes with oligonucleotides. Liposomes were made with a zwitterionic lipid, DOPE, and a cationic lipid, either DOTAP or DC-Chol. Oligonucleotides were the 20-base single strand polyA, the 20-base single strand polyT, and the corresponding double strand dsAT. The zeta potential as a function of the oligonucleotide/lipid(+) ratio gave an S-shaped titration curve. Well-defined surface potential changes took place upon charge compensation between the cationic lipid heads and the phosphate groups on the oligonucleotides. The inversion point depended on the specific system under study. The bilayer properties and the changes that occurred with the incorporation of DNA fragments were also monitored by ESR spectroscopy of appropriately tailored spin probes. For all the systems investigated, the ESR spectra showed that no major alteration took place after lipoplex formation and molecular packing remained substantially unchanged. Both zeta potential and ESR measurements were in favor of an external mode of packing of the lipoplexes. (C) 2004 Elsevier B.V. All rights reserved.