Identification of possible sources of nanotoxicity from carbon nanotubes inserted into membrane bilayers using membrane interaction quantitative structure-activity relationship analysis
Identification of possible sources of nanotoxicity from carbon nanotubes inserted into membrane bilayers using membrane interaction quantitative structure-activity relationship analysis
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DOI：
10.1021/tx700392b
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发表时间：
2008-02-01
影响因子：
4.1
通讯作者：
Hopfinger, Anton J.
中科院分区：
文献类型：
--
作者：
Liu, Jianzhong;Hopfinger, Anton J.
采用膜相互作用定量构效关系方法，研究了碳纳米管在DMPC膜双层中的插入对细胞毒性的4种可能来源.比较（i）的膜双层的结构组织，（ii）的膜双层的动力学特征，和（iii）跨膜双层的小极性分子的运输进行，和没有;碳纳米管插入到双层。进行第四项研究以确定溶剂化离子通过插入的纳米管的运输如何可能改变膜双层的结构。由于碳纳米管的插入，双层中发生了两个大的变化。首先，DMPC双层分子的堆积发生变化，其从纳米管延伸至少18埃，并且包括直接围绕纳米管产生相对开放的、未占据的2-4埃厚的圆柱形环。第二，同样的双层结构，经历了结构组织的变化，也变得比没有插入纳米管时更刚性。溶剂化的钙离子被预测优先通过插入的纳米管相比，水合钠离子，但溶剂化的钙离子也产生了改变，因为它通过纳米管的局部双层结构。在插入的纳米管的存在下，乙醇通过膜双层的总扩散系数增加约35%。由于插入的纳米管，尿素和咖啡因也经历了通过双层运输的扩散系数的增加，但这些增加小于乙醇。在纳米管的存在下，三种促渗剂中的每一种也更直接地扩散通过膜双层，特别是咖啡因和尿素。
Four possible sources of cellular toxicity due to the insertion of a carbon nanotube into a dimyristoylphosphatidylcholine (DMPC) membrane bilayer were explored using the membrane interaction quantitative structure-activity relationship methodology. Comparisons of (i) the structural organization of the membrane bilayer, (ii) dynamical features of the membrane bilayer, and (iii) transport of small polar molecules across the membrane bilayer were carried out with, and without; a carbon nanotube inserted into the bilayer. A fourth study was performed to determine how the transport of solvated ions through the inserted nanotube might alter the structure of the membrane bilayer. Two large changes in the bilayer occur due to insertion of the carbon nanotube. First, there is an alteration in the packing of the DMPC bilayer molecules, which extends at least 18 angstrom from the nanotube, and includes the creation of a relatively open, unoccupied cylindrical ring of 2-4 angstrom thickness directly around the nanotube. Second, the same bilayer structure, which undergoes the change in structural organization, also becomes much more rigid than when the nanotube is not inserted. Solvated calcium ions are predicted to preferentially transport through the inserted nanotube as compared to hydrated sodium ions, but the solvated calcium ion also produces an alteration in the local bilayer structure as it passes through the nanotube. The total diffusion coefficient of ethanol through the membrane bilayer increases by about 35% in the presence of the inserted nanotube. Urea and caffeine also undergo increases in their diffusion coefficients for transport through the bilayer, due to the inserted nanotube, but these increases are less than that of ethanol. Each of the three penetrants also diffuses more directly through the membrane bilayer in the presence of the nanotube, especially caffeine and urea.