Abstract：
Lipid membranes that are separated from the surface of graphene by DNA tethers were prepared by surface functionalization with pyrene coupled to single-stranded DNA (ssDNA), followed by self-assembly of the mixture of ssDNA-functionalized phospholipid and the matrix phospholipids. The formation of uniform membranes was confirmed by fluorescence microscopy, and the structures of the systems before and after hybridization in the direction perpendicular to the global plane of the membranes were investigated using high-energy X-ray reflectivity. The thickness values of the DNA spacers (15 and 37 bp) calculated from the best-fit results were less than the expected thicknesses of the double-stranded DNA (dsDNA) chains taking the upright conformation, indicating that the DNA spacers are tilted with respect to the direction normal to the surface. The Young\'s moduli of the DNA-tethered membranes obtained by AFM nanoindentation showed higher values than the membranes with no DNA tethers, which suggests that the DNA layer resists against the compression, lifting up the membrane. Intriguingly, the presence of DNA tethers caused no increase in the yield depth. The smaller thickness values as well as the unchanged yield depth suggest that the dsDNA chains can tilt and rotate, which can be attributed to the flexible pyrene-DNA junction.
摘要：
通过与单链DNA（ssDNA）偶联的芘进行表面官能化，制备了通过DNA系链与石墨烯表面分离的脂膜。然后是ssDNA官能化磷脂和基质磷脂的混合物的自组装。通过荧光显微镜证实了均匀膜的形成，并使用高能X射线反射率研究了在垂直于膜全局平面的方向上杂交前后系统的结构。从最佳拟合结果计算的DNA间隔区的厚度值（15和37bp）小于采用直立构象的双链DNA（dsDNA）链的预期厚度，表明DNA间隔区相对于垂直于表面的方向倾斜。通过AFM纳米压痕获得的DNA系链膜的杨氏模量显示出比没有DNA系链的膜更高的值，这表明DNA层抵抗压缩，提升膜。有趣的是，DNA系链的存在没有引起产量深度的增加。较小的厚度值以及未改变的产量深度表明dsDNA链可以倾斜和旋转，这可以归因于柔性芘-DNA连接。
