Zenhausern F, Adrian M, Descouts P
Group of Applied Physics, Geneva, Switzerland.
J Electron Microsc (Tokyo). 1993 Dec;42(6):378-88.
In this study, we present the scanning force and electron microscopic visualization of single molecules of fibronectin either frozen hydrated or adsorbed onto metallic and polymeric surfaces with different solid surface tensions. The surfaces were characterized by dynamic contact angle measurements, X-ray photo emission spectroscopy (XPS or ESCA) and scanning force microscopy. The proteins were prepared by fast protein liquid chromatography (FPLC) and characterized by gel electrophoresis. Protein films on surfaces were investigated by surface plasmon resonance spectroscopy and directly imaged by scanning force microscopy. The spreading of the adsorbed fibronectin revealed dependence on the chemical composition and the solid surface tension. Structure of fibronectin in solution as well as on solid interface appeared as an extended straight strand as obtained by imaging with electron and scanning probe microscopies. Imaging of DNA was performed by scanning force microscopy to test the accuracy and reproducibility of our measurements. The measured contour lengths were accurate and the larger widths were caused by convolution of the tip shape and sample. Frictional forces during the scan have been of significant contribution in the imaging mechanism. Moreover, this work demonstrated that scanning force microscopy can be used for mapping the orientation and organization of protein film adsorbed onto various surfaces at the nanoscale.
在本研究中，我们展示了纤连蛋白单分子的扫描力和电子显微镜可视化，这些单分子处于冷冻水合状态，或吸附在具有不同固体表面张力的金属和聚合物表面上。通过动态接触角测量、X射线光电子能谱（XPS或ESCA）和扫描力显微镜对这些表面进行了表征。蛋白质通过快速蛋白质液相色谱（FPLC）制备，并通过凝胶电泳进行表征。通过表面等离子体共振光谱对表面上的蛋白质膜进行了研究，并通过扫描力显微镜直接成像。吸附的纤连蛋白的铺展显示出对化学成分和固体表面张力的依赖性。通过电子显微镜和扫描探针显微镜成像，溶液中以及固体界面上的纤连蛋白结构呈现为一条伸展的直线链。通过扫描力显微镜对DNA进行成像，以测试我们测量的准确性和可重复性。测得的轮廓长度是准确的，较大的宽度是由尖端形状和样品的卷积造成的。扫描过程中的摩擦力在成像机制中起了重要作用。此外，这项工作表明扫描力显微镜可用于在纳米尺度上绘制吸附在各种表面上的蛋白质膜的取向和组织图。
