Honciuc Andrei, Baptiste Denver Jn, Schwartz Daniel K
Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80309, USA.
Langmuir. 2009 Apr 21;25(8):4339-42. doi: 10.1021/la9004246.
The adsorption, interfacial mobility, and desorption of amphiphilic molecules are extremely sensitive to the chemical properties of the interface at which they adsorb; we demonstrate here that this sensitivity can be used to map subtle spatial variations of surface hydrophobicity. We have used total internal reflection fluorescence microscopy to observe the dynamic behavior of individual fluorescently labeled fatty acid molecules at the interface between water and a hydrophobically modified fused silica surface. Patterned surfaces were prepared by photodegradation of trimethylsilane-modified surfaces using a contact photomask; the degree of hydrophobic contrast was varied by controlling the dose of ultraviolet radiation. Cumulative images of single-molecule fluorescence, integrated over various exposure times, exhibited structural features consistent with the photopattern, and the fluorescence contrast was systematically related to the hydrophobic contrast. Lateral force microscopy was also used to characterize the patterned surfaces and provided qualitative images when the hydrophobic contrast was relatively high. However, the fluorescent probes provided more sensitive, reproducible, and reliable images of the lateral hydrophobic variations.
两亲分子的吸附、界面迁移率和解吸对其吸附界面的化学性质极为敏感；我们在此证明，这种敏感性可用于绘制表面疏水性的细微空间变化图。我们利用全内反射荧光显微镜观察了单个荧光标记脂肪酸分子在水与疏水改性熔融石英表面之间界面处的动态行为。通过使用接触光掩膜对三甲基硅烷改性表面进行光降解制备图案化表面；通过控制紫外线辐射剂量来改变疏水对比度。在不同曝光时间上积分的单分子荧光累积图像呈现出与光图案一致的结构特征，并且荧光对比度与疏水对比度系统相关。横向力显微镜也用于表征图案化表面，当疏水对比度相对较高时可提供定性图像。然而，荧光探针提供了更灵敏、可重复且可靠的横向疏水变化图像。
