生物谷报道：美国科学家的一项最新研究表明，单壁碳纳米管能够严重破坏大肠杆菌（E. coli）等细菌的细胞壁，从而将其杀灭。相关论文发表在美国化学学会的《朗缪尔》（Langmuir）杂志上。
在美国化学学会的一项预审中，该项研究被认为“首次找到了碳纳米管具有强大抗菌活性的直接证据，将有助于解决细菌抗药性这一日益突现的问题。”
论文高级作者、美国耶鲁大学化学和环境工程系主任Menachem Elimelech表示，“我们开始这项研究是基于对纳米管在水环境和食物链中潜在毒性的关注。由于碳纳米管只有人类头发丝的千分之一粗细，因此很容易进入细胞。不过，科学家对纳米管如何与人类和环境进行相互作用知之甚少。”
在最新的研究中，研究人员在有碳纳米管存在的情况下培育实验模型——大肠杆菌近一个小时。结果发现，只要病菌与单壁碳纳米管直接接触，就会被彻底杀灭。Elimelech推测，可能是长而细的碳纳米管刺破了细胞，从而产生伤害。同时，研究排除了金属毒性作祟的可能，因为为了避免金属污染，单壁碳纳米管的合成和净化过程都十分严格。
Elimelech小组目前正在研究多壁碳纳米管的毒性，初步的结论是它比单壁碳纳米管的毒性要弱。此外，研究人员也致力于在更广泛的细菌种类中进行类似实验，以期更好地理解碳纳米管破坏细胞的机制。（科学网 任霄鹏/编译）
英文全文:
Langmuir, 23 (17), 8670 -8673, 2007. 10.1021/la701067r S0743-7463(70)01067-3
Web Release Date: July 21, 2007 Copyright © 2007 American Chemical Society
Single-Walled Carbon Nanotubes Exhibit Strong Antimicrobial Activity
Seoktae Kang, Mathieu Pinault, Lisa D. Pfefferle, and Menachem Elimelech*
Department of Chemical Engineering, Yale University, P.O. Box 208286, New Haven, Connecticut 06520-8286
Received April 12, 2007
In Final Form: June 12, 2007
Abstract:
We provide the first direct evidence that highly purified single-walled carbon nanotubes (SWNTs) exhibit strong antimicrobial activity. By using a pristine SWNT with a narrow diameter distribution, we demonstrate that cell membrane damage resulting from direct contact with SWNT aggregates is the likely mechanism leading to bacterial cell death. This finding may be useful in the application of SWNTs as building blocks for antimicrobial materials.
Carbon-based nanomaterials, such as fullerene and carbon nanotubes (CNTs), exhibit unique size- and structure-dependent optical, electronic, magnetic, thermal, chemical, and mechanical properties.1 As a result, it is not surprising that these nanomaterials have been considered for use in numerous applications, including the fabrication of superconductors, optical devices, sensors, energy storage devices, fuel cells, and catalysts.2 However, such extraordinary physical and chemical properties are accompanied by concerns about possible adverse effects of these materials on biological systems. In particular, applications that use single-walled carbon nanotubes (SWNTs) for biosensors,3 drug and vaccine delivery transporters,4,5 and novel biomaterials6 increase the potential for encounters between SWNTs and humans and the ecosystem. Future commercial development of nanotechnology may also lead to the discharge of SWNTs into the environment.
Information concerning the potential toxicity from exposure to SWNTs and their environmental impact is scarce, often debated,7 and focused on human cells.8-11 The toxicity of SWNTs to human cells has been observed to vary with SWNT functionalization and the concentration of the solubilizing agent (i.e., surfactants),12,13 as well as with SWNT physicochemical properties such as structure, diameter, cleanliness (e.g., % metal), and defect level.14 In these studies, however, commercial SWNTs were used, and characterization was not well defined. Furthermore, for these SWNTs, factors such as mean diameter, diameter distribution, metal content, and defect level cannot be independently varied because of limitations of the SWNT synthesis, cleaning, and separation processes. Commercial SWNTs have generally been treated with strong acids and contain on average 4.5-15% metal and other impurities.15 Only a handful of groups can produce SWNTs with a narrow diameter distribution.16
