Gemini表面活性剂与DNA在气/液界面上的相互作用

在气/液界面上, 阳离子表面活性剂可以通过静电作用与阴离子型的脱氧核糖核酸(DNA)分子形成复合膜, 并压缩沉积得到LB(Langmuir-Blodget)膜. 利用表面压-表面积(π-A)曲线、原子力显微镜(AFM)和石英晶体微天平(QCM)研究了阳离子Gemini表面活性剂(C₁₈H₃₇(CH₃)₂N⁺-(CH₂)_s-N⁺(CH₃)₂C₁₈H₃₇]·2Br^-, 简写为18-s-18, s=3, 4, 6, 8, 10, 12)与DNA(双链DNA(dsDNA), 单链DNA(ssDNA))之间的相互作用, 并对18-s-18在不同下相表面的分子面积进行了比较. 实验结果表明连接基团和下相的DNA对Gemini表面活性剂在气/液界面上的性质有很大影响. 此外, Gemini表面活性剂在界面上对DNA的吸附能力与它们之间的相互作用方式密切相关.

Interaction between Gemini and DNA at the Air/Water Interface

Monolayers may be obtained by an electrostatic force between cationic surfactants and anionic electrolyte deoxyribonucleic acid (DNA) molecules, and a corresponding Langmuir-Blodgett (LB) complex monolayer can be fabricated by compression and deposition of the monolayer at the air/water interface. In this work, the interaction between cationic Gemini surfactants (C18H37(CH3)2N+-(CH2)s-N+(CH3)2- C18H37]·2Br-, abbreviated 18-s-18, s=3, 4, 6, 8, 10, 12) and double-strand DNA (dsDNA)/single-strand DNA (ssDNA) was investigated by surface pressure-surface area (π-A) isotherms, atomic force microscope (AFM), and Quartz crystal microbalance (QCM). Moreover, the limiting molecular areas of 18-s-18 on different subphases were compared. We found that the spacer and the subphase greatly influence the properties of the Gemini surfactants at the air/water interface. In addition, we conclude that the adsorption capacity of the Gemini surfactants with DNA is closely related to their interaction modes.