We assembled 1, 4, or 20 doxorubicin (DOX) molecules on the surface of (9, 9) carbon nanotubes (CNTs) as well as 1, 4, 12, or 24 DOX molecules on the surface of –COOH functionalized (9, 9) CNTs (f-CNT) by the density functional tight binding method. The stable assembled structural properties and the interaction energies, such as the total interaction energy, the interaction energy between the CNT/f-CNT and DOX, and the interaction energy between DOX molecules, were analyzed in detail for the complexes. We found that the complex become more stable as the number of DOX molecules increased; the high density adsorption of DOX molecules on the surface of the CNT/f-CNT is more advantageous. To further understand the interactions, the hydrogen bonds, the highest occupied molecular orbitals and the lowest unoccupied molecular orbitals were analyzed. We further investigated the stability and thermodynamic characteristics of the 20DOX/CNT and 24DOX/f-CNT complexes at room temperature via molecular dynamic simulations. The root mean squared displacement and the total energy variations were studied. This work offers a new strategy to assemble a high density of DOX molecules on the surfaces of CNTs.

我们在 (9, 9) 碳纳米管 (CNT) 表面组装了 1、4 或 20 个阿霉素 (DOX) 分子，并在 –COOH 功能化 (9, 9) CNTs (f-CNT) 通过密度泛函紧密结合方法。详细分析了复合物的稳定组装结构特性和相互作用能，如总相互作用能、CNT/f-CNT 与 DOX 之间的相互作用能以及 DOX 分子之间的相互作用能。我们发现复合物随着 DOX 分子数量的增加而变得更加稳定；DOX分子在CNT/f-CNT表面的高密度吸附更有优势。为了进一步了解相互作用，氢键，最高占据分析了分子轨道和最低未占分子轨道。我们通过分子动力学模拟进一步研究了 20DOX/CNT 和 24DOX/f-CNT 复合物在室温下的稳定性和热力学特性。研究了均方根位移和总能量变化。这项工作提供了一种在碳纳米管表面组装高密度 DOX 分子的新策略。