Complexation of Lipofectamine and Cholesterol-Modified DNA Sequences Studied by Single-Molecule Fluorescence Techniques

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• 作者：Anca Margineanu ; Steven De Feyter ; Sergey Melnikov ; Damien Marchand ; Arthur van Aerschot ; Piet Herdewijn ; Satoshi Habuchi ; Frans C. De Schryver ; Johan Hofkens
• 刊名：Biomacromolecules
• 出版年：2007
• 出版时间：November 2007
• 年：2007
• 卷：8
• 期：11
• 页码：3382 - 3392
• 全文大小：315K
• 年卷期：v.8,no.11(November 2007)
• ISSN：1526-4602

文摘

Lipoplex formation for normal and cholesterol-modified oligonucleotides is investigated by fluorescence correlationspectroscopy (FCS). To overcome the problems related to the fitting of autocorrelation curves when fluorescencebursts are present, the baseline fluorescence levels and the fluorescence bursts in the same trace were separatelyanalyzed. This approach was not previously used in FCS studies of lipoplexes and allowed a more detailedcharacterization of this heterogeneous system. From the baseline levels, the number of free/bound DNA moleculesand the presence of tens to hundreds of nanometer-sized lipoplexes were estimated using various mathematicalmodels. Analysis of the fluorescent bursts provided an indication about the sizes of the lipoplexes, the number ofDNA molecules in these aggregates, and the relative amount of lipids in each aggregate. An explanation for thehigher transfection efficiency previously reported for one of the cholesterol-modified oligonucleotide compoundswas found in relation to the formation of large size lipoplexes.