加州大学的两名工程师发现了活细菌体内的半导体纳米管，此项发现将有助于开发出一套全新的纳米电子器件。
这是首次发现纳米管可以由生物直接合成，而不需要通过化学的方法。与现行的化学方法相比，这种方法更经济，对环境更为友好。研究成果刊登在了12月9日的Proceedings of the National Academy of Sciences在线版上。
Bourns工程学院的Nosang V. Myung副教授是此项研究的主要研究者，他的博士后研究员Bongyoung Yoo发现了细菌Shewanella会产生由硫化砷组成的纳米管（arsenic-sulfide nanotube）。这种纳米管与化工合成的纳米管相比，有着独特的物理化学性质。
当前，世界上通用的电子器件——从电脑到太阳能电池——都依赖于化工合成。这种方法不仅耗能多，而且还留下了非常严重的环境污染问题。Myung介绍说，寻找一种绿色的半导体管生产工艺是目前科学与工程领域中的一项研究热点。
这种由细菌合成的具有光敏活性的纳米管表现出了金属的一些特性，例如，它具有光电导特性。研究者称这些特性将可能为下一代的纳米和光电子器件提供新的功能。
有一个过程现在还没能研究清楚，Shewanella细菌分泌出了多糖，这些多糖似乎是作为生产纳米管的模板，Myung解释说。如果将来能发现一种可以生产硫化镉或更有优势的半导体材料，那么此项技术的意义将不同凡响。
“这给未来研究指明了方向，我们的工作才刚刚开始，”他最后补充道，“Shewanella的每个物种都有可能为我们的生产工艺带来新的思路。”
原始出处:
Published online before print December 7, 2007
Proc. Natl. Acad. Sci. USA, 10.1073/pnas.0707595104
Biogenic formation of photoactive arsenic-sulfide nanotubes by Shewanella sp. strain HN-41
Ji-Hoon Lee*, Min-Gyu Kim, Bongyoung Yoo, Nosang V. Myung, Jongsun Maeng, Takhee Lee, Alice C. Dohnalkova¶, James K. Fredrickson¶, Michael J. Sadowsky||, and Hor-Gil Hur*,**
*Department of Environmental Science and Engineering and International Environmental Research Center and Department of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 500-712, Republic of Korea; Pohang Accelerator Laboratory, Pohang, Gyeongbuk 790-784, Republic of Korea; Department of Chemical and Environmental Engineering and Center for Nanoscale Science and Engineering, University of California, Riverside, CA 92521; ¶Environmental Molecular Sciences Laboratory and Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352; and ||Department of Soil, Water, and Climate and BioTechnology Institute, University of Minnesota, St. Paul, MN 55108
Edited by James M. Tiedje, Michigan State University, East Lansing, MI, and approved October 23, 2007 (received for review August 11, 2007)
Abstract
Microorganisms facilitate the formation of a wide range of minerals that have unique physical and chemical properties as well as morphologies that are not produced by abiotic processes. Here, we report the production of an extensive extracellular network of filamentous, arsenic-sulfide (As-S) nanotubes (20–100 nm in diameter by 30 µm in length) by the dissimilatory metal-reducing bacterium Shewanella sp. HN-41. The As-S nanotubes, formed via the reduction of As(V) and S2O, were initially amorphous As2S3 but evolved with increasing incubation time toward polycrystalline phases of the chalcogenide minerals realgar (AsS) and duranusite (As4S). Upon maturation, the As-S nanotubes behaved as metals and semiconductors in terms of their electrical and photoconductive properties, respectively. The As-S nanotubes produced by Shewanella may provide useful materials for novel nano- and opto-electronic devices.
