Nanoscopic structure of DNA condensed for gene delivery
Nanoscopic structure of DNA condensed for gene delivery
复制标题
DOI：
10.1093/nar/25.15.3095
复制
发表时间：
1997-08-01
影响因子：
14.9
通讯作者：
Monaco, L
中科院分区：
文献类型：
--
作者：
Dunlap, DD;Maggi, A;Monaco, L
用扫描力显微镜对生理溶液中不同化学计量的脂精胺或聚乙烯亚胺制备的DNA凝聚物进行了检测。第一次，单个DNA链在没有干燥的不完全冷凝物中被清晰地观察到。使用亚饱和浓度的脂精胺，观察到离散的凝聚核通常被折叠的DNA环包围。在聚亚胺诱导的缩聚过程中也出现了类似的DNA环的堆积。增加凝聚剂的量导致初始凝聚核通过折叠而不是缠绕DNA而逐渐合并或聚集。在阳离子脂质或聚合物与DNA的过饱和电荷比下，缩合物的大小小于或等于先前在电子显微照片中测量到的大小。聚乙烯亚胺凝聚物比脂精胺凝聚物更致密，当使用在2-4倍电荷过剩时，两者都产生更均匀的致密质粒。凝聚体的大小和形态可能影响其转染效率。
Scanning force microscopy was used to examine DNA condensates prepared with varying stoichiometries of lipospermine or polyethylenimine in physiological solution. For the first time, individual DNA strands were clearly visualized in incomplete condensates without drying. Using lipospermine at sub-saturating concentrations, discrete nuclei of condensation were observed often surrounded by folded loops of DNA. Similar packing of DNA loops occurred for polyethylenimine-induced condensation. Increasing the amount of the condensing agent led to the progressive coalescence or aggregation of initial condensation nuclei through folding rather than winding the DNA. At over-saturating charge ratios of the cationic lipid or polymer to DNA, condensates had sizes smaller than or equal to those measured previously in electron micrographs. Polyethylenimine condensates were more compact than lipospermine condensates and both produced more homogeneously compacted plasmids when used in a 2-4-fold charge excess. The size and morphology of the condensates may affect their efficiency in transfection.