Robotic Research Laboratory, Center of Excellence in Experimental Solid Mechanics and Dynamics, School of Mechanical Engineering, Iran University of Science and Technology, Narmak, Tehran, Iran.
Robotic Research Laboratory, Center of Excellence in Experimental Solid Mechanics and Dynamics, School of Mechanical Engineering, Iran University of Science and Technology, Narmak, Tehran, Iran.
Colloids Surf B Biointerfaces. 2017 Oct 1;158:102-111. doi: 10.1016/j.colsurfb.2017.06.017. Epub 2017 Jun 24.
Nanocarriers are useful tools in biological and medical research fields. In nanomanipulation, a nondestructive and successful process can be achieved by using nanocarriers. In this paper, a nonclassical multiscale approach has been presented for modeling a single strand DNA (ssDNA) manipulation based on AFM. To achieve a nondestructive nanomanipulation process, carbon nanotube (CNT) has been used as a nanocarrier. AFM setup has been separated into a Micro field (MF) and a Nano field (NF). The governing equations of the MF have been derived based on Kirchhoff plate model and a modified couple stress theory. The NF has been modeled by molecular dynamics (MD) method. A set of nanomanipulations has been performed for the free ssDNA and the ssDNA inside the nanocarrier (shielded ssDNA) on three types of substrates. The exerted forces on the free ssDNA and the shielded ssDNA have been compared for manipulation on various substrates. The results show that using the nanocarrier reduces the manipulation force considerably. The results of RMSD as a general geometrical criterion have illustrated that the maximum damage occurs on the golden substrate for free ssDNA. Elongation and curvature criteria have been presented to investigate the ssDNA deformation in detail. The elongation and curvature criteria have been shown that using a nanocarrier is a good approach for a successful and nondestructive nanomanipulation. Finally it can be concluded that the manipulation process of free ssDNA on silicon substrate is successful as well as the manipulation process of the shielded ssDNA on all three types of substrates.
纳米载体在生物和医学研究领域是非常有用的工具。在纳米操作中，通过使用纳米载体可以实现非破坏性和成功的过程。在本文中，提出了一种非经典多尺度方法，用于基于原子力显微镜（AFM）对单链 DNA（ssDNA）操作进行建模。为了实现非破坏性的纳米操作过程，使用了碳纳米管（CNT）作为纳米载体。将 AFM 装置分为微场（MF）和纳米场（NF）。基于 Kirchhoff 板模型和修正的偶应力理论推导出了 MF 的控制方程。NF 通过分子动力学（MD）方法进行建模。对三种类型的衬底上的自由 ssDNA 和纳米载体内部的 ssDNA（屏蔽 ssDNA）进行了一组纳米操作。比较了在各种衬底上对自由 ssDNA 和屏蔽 ssDNA 施加的力，以进行操作。结果表明，使用纳米载体可以大大降低操作力。均方根偏差（RMSD）作为一般几何标准的结果表明，对于自由 ssDNA，最大损伤发生在金衬底上。提出了伸长率和曲率标准，以详细研究 ssDNA 的变形。伸长率和曲率标准表明，使用纳米载体是成功且非破坏性的纳米操作的一种好方法。最后可以得出结论，在硅衬底上对自由 ssDNA 的操作过程是成功的，而在三种类型的衬底上对屏蔽 ssDNA 的操作过程也是成功的。
