原子力显微镜拉伸吸附在金膜表面的短单链DNA分子(英文)

Stretching Short Single-stranded DNA Adsorbed on Gold Surface by Atomic Force Microscope

对单根DNA分子的操纵和拉伸可以直接研究DNA的弹性等力学性质.首先通过将金沉积到云母表面制备了表面粗糙度小于0.3nm的金膜,然后一段硫代的单链DNA(100bases)吸附到金膜表面.利用原子力显微镜观察不同浓度的DNA吸附在金膜上的表面形貌.进一步用原子力显微镜的力曲线模式拉伸DNA分子,在50%的情况下DNA可以被针尖拉伸,观察到了由于针尖和DNA分子间作用力的不同导致的多种不同力曲线.

The manipulation and direct mechanical measurement of single DNA molecule could give much information about its elastic properties. Single stranded DNA （ssDNA） of 100 bases was adsorbed onto flat gold surface fabricated by depositing gold onto mica surface. Atomic force microscope （AFM） was used to observe the surface topography with different ssDNA concentration. Then the ssDNAs were stretched by AFM tip and in 50% cases ssDNAs could be stretched.Various kinds of force curves have been observed due to the different interaction between AFM tip and ssDNAs.