Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada.
J Colloid Interface Sci. 2012 Aug 15;380(1):25-33. doi: 10.1016/j.jcis.2012.04.061. Epub 2012 May 10.
A model for a carbon nanotube (CNT)-DNA hybrid embedded in an electrolyte solution is developed. The DNA charges are smeared out uniformly onto a cylindrical surface covering the CNT and the response of the CNT to the DNA charges is captured using the one-dimensional density of states (1D DOS) proposed by Mintmire et al. Coupled with the Debye-Hückel equation for the electrolyte, the expressions for the electric potential of the hybrid are obtained for both metallic and semiconducting CNT cores. For the surface charge density of the cylinder corresponding to the physically measured wrapping angles of a single-stranded DNA around a CNT, the developed model predicts that the induced charges on a semiconducting CNT are about one order of magnitude smaller than the DNA charges, while the induced charges on a metallic CNT can be comparable in magnitude to the DNA charges. Because of this, the magnitude of the electric potential for a metallic CNT-DNA hybrid can be as much as approximately equal 30% smaller than that for a semiconducting one. This result can be used to explain the experiments on DNA-assisted CNT separation using ion exchange chromatography.
建立了一种嵌入在电解质溶液中的碳纳米管（CNT）-DNA 杂化模型。DNA 电荷被均匀地涂抹在覆盖 CNT 的圆柱面上，并用 Mintmire 等人提出的一维态密度（1D DOS）来捕捉 CNT 对 DNA 电荷的响应。结合电解质的 Debye-Hückel 方程，得到了金属和半导体 CNT 核的杂化电势表达式。对于与单链 DNA 围绕 CNT 的物理测量缠绕角相对应的圆柱面的表面电荷密度，所开发的模型预测，半导体 CNT 上的感应电荷比 DNA 电荷小一个数量级，而金属 CNT 上的感应电荷可以与 DNA 电荷相当。因此，金属 CNT-DNA 杂化的电势幅度可以比半导体 CNT-DNA 杂化的电势幅度小约 30%。这个结果可以用来解释使用离子交换色谱法进行 DNA 辅助 CNT 分离的实验。
