We developed the models and algorithms to describe two main artefacts of AFM: (i) broadening effect and (ii) decreased heights of profiles for individual objects adsorbed on a hard substrate. It was shown how to measure elastic properties of a single adsorbed microobject. From the viewpoint of contact deformation theory we analysed mechanism of AFM visualisation of an atomic (molecular) structure of a flat surface. We tested technique of immobilisation on a substrate for free single-stranded RNA molecules in an extended state. Using AFM we visualised stages of processes of RNA release from protein coat of tobacco mosaic virus particles. The asymmetry of this process regarding two ends of a macromolecule was confirmed. The dynamics of compaction for DNA T4 molecules was traced using AFM in real time regime. The partially compacted macromolecules were clearly resolved. We detected that the partially compacted structures consisted of toroidal parts formed by different macromolecular strands. The real geometry of the compacted structures was reconstructed on the basis of systematic AFM measurements. That allowed us to calculate the amount of molecules combining each condensed DNA particle. We demonstrated clear benefits of horizontal deposition method for formation of LB films. Using AFM we achieved molecular resolution for some thin film coating and detected lattice parameters with the precision determined by the errors within a few percent. We demonstrated that the structure of the film is determined by the concurrence of several factors: by the closest packing principle for hydrocarbon tails, by the values of surface areas of polar heads at water subphase as well as by the substrate influence.
First-principles Study of Physisorption of Nucleic Acid Bases on Small-Diameter Carbon Nanotube
我们报告了我们基于密度泛函理论对核酸碱基分子腺嘌呤（A）、胞嘧啶（C）、鸟嘌呤（G）、胸腺嘧啶（T）和尿嘧啶（U）与单壁碳纳米管（CNT）相互作用的第一性原理研究结果。具体而言，重点是物理吸附的基础分子上的外壁（5，0）金属CNT拥有一个最小的直径可能。与大直径的碳纳米管相比，发现在高曲率的情况下，物理吸附能降低。基础分子表现出显着不同的相互作用强度，和计算的结合能遵循的层次G > A > T > C > U，这似乎是独立的管曲率。基础分子和CNT之间的相互作用中的稳定因素由分子极化率主导，该分子极化率允许在它们之间诱导弱吸引分散力。本研究提供了一个更好的理解脱氧核糖核酸（DNA）或核糖核酸（RNA）中的碱基序列对它们与不同直径的碳纳米管的相互作用的作用。
