Charge-signal multiplication mediated by urea wires inside Y-shaped carbon nanotubes.
Charge-signal multiplication mediated by urea wires inside Y-shaped carbon nanotubes.
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DOI：
10.1063/1.4890725
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发表时间：
2014-07
期刊：
影响因子：
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通讯作者：
Meisel Lv;Bing He;Zengrong Liu;P. Xiu;Y. Tu
中科院分区：
文献类型：
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作者：
Meisel Lv;Bing He;Zengrong Liu;P. Xiu;Y. Tu
在以前的研究中，我们报道了分子动力学（MD）模拟，表明限制在Y形单壁碳纳米管（Y-SWNTs）内的单行水线具有强大和鲁棒的转换和倍增电荷信号的能力[Y. S. Tu，P. Xiu，R. Z. Wan，J. Hu，R. H. Zhou和H. P. Fang，Proc. Natl. Acad. Sci. U.S.A. 106，18120（2009）; Y. Tu，H. Lu，Y. Zhang，T. Huynh和R. Zhou，J.Chem.Phys.138，015104（2013）]。观察信号倍增是否可以通过具有更大偶极矩的其他种类的极性分子实现（这使得实验实现更容易）是有趣的。在这篇文章中，我们使用分子动力学模拟来研究尿素介导的信号转换和倍增与Y-单壁碳纳米管。我们观察到，当Y-SWNT与外部电荷的幅度1.0 e（在单电子水平的信号的模型）溶剂化在1 M尿素溶液中，尿素可以诱导干燥的Y-SWNT和填充其内部的单行，形成Y形尿素线。外部电荷可以有效地控制尿素丝在主通道内的偶极取向（即，该信号可以容易地转换），并且通过调节Y-SWNT的分叉分支通道中的尿素线的偶极取向，该信号可以进一步倍增为2个（或更多个）输出信号。这种显着的信号传导能力源于极端限制下尿素线的强偶极诱导有序性。我们还讨论了尿素与水相比在信号倍增方面的优势，以及我们的研究结果的鲁棒性和生物学意义。这项研究提供了通过使用尿素分子（或其他极性有机分子）与Y形纳米通道倍增信号的可能性，也可能有助于理解物理和生物系统中信号传导背后的机制。
In previous studies, we reported molecular dynamics (MD) simulations showing that single-file water wires confined inside Y-shaped single-walled carbon nanotubes (Y-SWNTs) held strong and robust capability to convert and multiply charge signals [Y. S. Tu, P. Xiu, R. Z. Wan, J. Hu, R. H. Zhou, and H. P. Fang, Proc. Natl. Acad. Sci. U.S.A. 106, 18120 (2009); Y. Tu, H. Lu, Y. Zhang, T. Huynh, and R. Zhou, J. Chem. Phys. 138, 015104 (2013)]. It is fascinating to see whether the signal multiplication can be realized by other kinds of polar molecules with larger dipole moments (which make the experimental realization easier). In this article, we use MD simulations to study the urea-mediated signal conversion and multiplication with Y-SWNTs. We observe that when a Y-SWNT with an external charge of magnitude 1.0 e (the model of a signal at the single-electron level) is solvated in 1 M urea solutions, urea can induce drying of the Y-SWNT and fill its interiors in single-file, forming Y-shaped urea wires. The external charge can effectively control the dipole orientation of the urea wire inside the main channel (i.e., the signal can be readily converted), and this signal can further be multiplied into 2 (or more) output signals by modulating dipole orientations of urea wires in bifurcated branch channels of the Y-SWNT. This remarkable signal transduction capability arises from the strong dipole-induced ordering of urea wires under extreme confinement. We also discuss the advantage of urea as compared with water in the signal multiplication, as well as the robustness and biological implications of our findings. This study provides the possibility for multiplying signals by using urea molecules (or other polar organic molecules) with Y-shaped nanochannels and might also help understand the mechanism behind signal conduction in both physical and biological systems.