Knapp H F, Wiegräbe W, Heim M, Eschrich R, Guckenberger R
Max Planck Institut für Biochemie, Abteilung Molekulare Strukturbiologie, Martinsried, Germany.
Biophys J. 1995 Aug;69(2):708-15. doi: 10.1016/S0006-3495(95)79946-5.
A simple method for rendering atomic force microscope tips and cantilevers hydrophilic or hydrophobic through glow discharge in an appropriate gas atmosphere is introduced. Force curves at different humidities of these modified cantilevers were taken on freshly cleaved mica (hydrophilic surface) and on a monolayer of dipalmitoylphosphatidylethanolamine transferred onto mica (hydrophobic surface) to characterize the behavior of the cantilevers on hydrophilic and hydrophobic surfaces. Furthermore, Langmuir-Blodgett bilayers, with a dipalmitoylphosphatidylethanolamine bottom layer and a dipalmitoylphosphatidylcholine top layer, were imaged in the constant force mode in a multimode atomic force microscope in air under controlled humidity conditions. The friction and elasticity signal were recorded parallel to the topography. By varying the force exerted by the tip on the sample, different layers of the Langmuir-Blodgett system could be removed or flattened. Removal exposed underlying layers that exhibited a different friction and elasticity behavior. Furthermore, force scans with tips rendered hydrophobic were taken on the different layers of the sample to characterize the hydrophilic/hydrophobic nature of the layers. Only by combining the results obtained by the different methods can the structure of the lipid layer systems be identified.
介绍了一种通过在适当气体气氛中辉光放电使原子力显微镜探针和悬臂亲水或疏水的简单方法。在新鲜劈开的云母（亲水表面）和转移到云母上的二棕榈酰磷脂酰乙醇胺单分子层（疏水表面）上获取这些修饰悬臂在不同湿度下的力曲线，以表征悬臂在亲水和疏水表面上的行为。此外，在可控湿度条件下的空气中，在多模式原子力显微镜中以恒力模式对具有二棕榈酰磷脂酰乙醇胺底层和二棕榈酰磷脂酰胆碱顶层的朗缪尔-布洛杰特双层膜进行成像。平行于形貌记录摩擦和弹性信号。通过改变探针施加在样品上的力，可以去除或平整朗缪尔-布洛杰特系统的不同层。去除后会暴露出具有不同摩擦和弹性行为的下层。此外，在样品的不同层上使用疏水化的探针进行力扫描，以表征各层的亲水/疏水性质。只有结合不同方法获得的结果，才能确定脂质层系统的结构。
