Park Hye-Young, Li Hung-Wing, Yeung Edward S, Porter Marc D
Ames Laboratory-USDOE, Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA.
Langmuir. 2006 Apr 25;22(9):4244-9. doi: 10.1021/la053100x.
This paper examines the single-molecule adsorption of YOYO-I-labeled lambda-DNA at compositionally patterned self-assembled monolayers (SAMs). The interactions of fluorescently labeled lambda-DNA molecule with the patterned SAMs, which are comprised of different functional groups (i.e., amine-, alcohol-, and acid-terminated thiolates), were monitored at optically transparent gold films using total internal reflection fluorescence microscopy. The role of solution pH, lambda-DNA concentration, and domain size was investigated. In addition to delineation of the relative adsorption strength as a function of terminal group identity (NH2 > COOH > OH), the potential importance of structural defects was also revealed. The latter result, found both at the disordered boundaries between domains and at adlayers in which structural order was affected by the length of the alkyl chain, points to the subtle but preferential adsorption of the "sticky ends" of lambda-DNA. These experiments also detected an intriguing dependence of adsorption with respect to domain size.
本文研究了YOYO-I标记的λ-DNA在组成图案化的自组装单分子层（SAMs）上的单分子吸附。使用全内反射荧光显微镜在光学透明金膜上监测荧光标记的λ-DNA分子与由不同官能团（即胺基、醇基和酸基封端的硫醇盐）组成的图案化SAMs之间的相互作用。研究了溶液pH值、λ-DNA浓度和区域尺寸的作用。除了描绘相对吸附强度与端基特性的函数关系（NH2 > COOH > OH）外，还揭示了结构缺陷的潜在重要性。后一结果在区域之间的无序边界以及结构顺序受烷基链长度影响的吸附层中均有发现，这表明λ-DNA“粘性末端”存在微妙但优先的吸附。这些实验还检测到吸附对区域尺寸的有趣依赖性。
