Dynamics of DNA Adsorption on and Release from SDS-DDAB Cat-Anionic Vesicles: a Multitechnique Study

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• 作者：Adalberto Bonincontro ; Maria Falivene ; Camillo La Mesa ; Gianfranco Risuleo ; Miriam Ruiz Pe&ntilde ; a
• 刊名：Langmuir
• 出版年：2008
• 出版时间：March 4, 2008
• 年：2008
• 卷：24
• 期：5
• 页码：1973 - 1978
• 全文大小：151K
• 年卷期：v.24,no.5(March 4, 2008)
• ISSN：1520-5827

文摘

DNA adsorption and release from cat-anionic vesicles made of sodium dodecylsulfate-dodecyldimethylammoniumbromide (SDS-DDAB) in nonstoichiometric amounts was investigated by different electrochemical, spectroscopic,and biomolecular strategies. The characterization of the vesicular system was performed by dynamic light scattering,which allowed estimating both its size and distribution function(s). The interaction dynamics was followed by dielectricspectroscopy and -potential, as well as by agarose gel electrophoresis, AGE. Also, circular dichroism, CD, measurementswere carried out, to ascertain possible structural rearrangements of DNA, consequent to the interactions with thecat-anionic vesicles. CD demonstrates that vesicle-bound DNA retains its native conformation. The results obtainedby the aforementioned techniques are consistent and indicate that binding saturation is obtained at a [DNA/vesicles]charge ratio close to 0.8, considering only the excess surface charges on the vesicles. This result is apparently incontradiction with a purely electrostatic approach and is tentatively ascribed to the distance between charges on thebiopolymer and the vesicle surface, respectively. A possible interpretation is discussed. The nucleic acid can becompletely retrieved from the vesicles upon addition of adequate amounts of SDS, which is the defective surfactantin the vesicular system. Precipitation of the poorly soluble SD-DDA salt results in an almost complete release ofDNA.