加州大學(xué)的兩名工程師發(fā)現(xiàn)了活細(xì)菌體內(nèi)的半導(dǎo)體納米管,，此項(xiàng)發(fā)現(xiàn)將有助于開發(fā)出一套全新的納米電子器件。
這是首次發(fā)現(xiàn)納米管可以由生物直接合成,，而不需要通過(guò)化學(xué)的方法,。與現(xiàn)行的化學(xué)方法相比，這種方法更經(jīng)濟(jì),，對(duì)環(huán)境更為友好,。研究成果刊登在了12月9日的Proceedings of the National Academy of Sciences在線版上。
Bourns工程學(xué)院的Nosang V. Myung副教授是此項(xiàng)研究的主要研究者,，他的博士后研究員Bongyoung Yoo發(fā)現(xiàn)了細(xì)菌Shewanella會(huì)產(chǎn)生由硫化砷組成的納米管（arsenic-sulfide nanotube）,。這種納米管與化工合成的納米管相比，有著獨(dú)特的物理化學(xué)性質(zhì),。
當(dāng)前,，世界上通用的電子器件——從電腦到太陽(yáng)能電池——都依賴于化工合成。這種方法不僅耗能多,，而且還留下了非常嚴(yán)重的環(huán)境污染問(wèn)題,。Myung介紹說(shuō)，尋找一種綠色的半導(dǎo)體管生產(chǎn)工藝是目前科學(xué)與工程領(lǐng)域中的一項(xiàng)研究熱點(diǎn),。
這種由細(xì)菌合成的具有光敏活性的納米管表現(xiàn)出了金屬的一些特性,，例如，它具有光電導(dǎo)特性,。研究者稱這些特性將可能為下一代的納米和光電子器件提供新的功能,。
有一個(gè)過(guò)程現(xiàn)在還沒(méi)能研究清楚，Shewanella細(xì)菌分泌出了多糖,，這些多糖似乎是作為生產(chǎn)納米管的模板,，Myung解釋說(shuō)。如果將來(lái)能發(fā)現(xiàn)一種可以生產(chǎn)硫化鎘或更有優(yōu)勢(shì)的半導(dǎo)體材料,，那么此項(xiàng)技術(shù)的意義將不同凡響,。
“這給未來(lái)研究指明了方向，我們的工作才剛剛開始,，”他最后補(bǔ)充道,，“Shewanella的每個(gè)物種都有可能為我們的生產(chǎn)工藝帶來(lái)新的思路,。”
原始出處:
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.
