根據(jù)美國(guó)布朗大學(xué)(Brown University)研究人員的研究發(fā)現(xiàn)，石墨烯 (grapheme)──這種被譽(yù)為半來半導(dǎo)體材料的新寵── 可能會(huì)破壞活細(xì)胞功能。如果布朗大學(xué)的毒性研究結(jié)果進(jìn)一步經(jīng)過多方研究證實(shí)的話，石墨烯最終可能會(huì)像碳納米管一樣被歸類在有害物質(zhì)范圍。 “石墨烯比碳納米管更容易產(chǎn)生，而且在許多應(yīng)用中都能取代碳納米管，”布朗大學(xué)病理學(xué)和實(shí)驗(yàn)室醫(yī)學(xué)系教授Agnes Kane表示。 石墨烯具有許多獨(dú)特的功能，但最重要的是它經(jīng)常是由天然礦物──石墨制造而來，其方式是經(jīng)由化學(xué)或機(jī)械剝離方式分離碳薄層，形成可能產(chǎn)生吸入暴露的干燥粉末。病理學(xué)家已經(jīng)針對(duì)碳納米管和其他有關(guān)的碳材料展開研究了，但是這是第一次針對(duì)2D納米材料進(jìn)行毒性測(cè)試。 Agnes Kane所主導(dǎo)的布朗大學(xué)研究團(tuán)隊(duì)在展開石墨烯的毒性研究后發(fā)現(xiàn)，就像碳奈米管一樣，石墨烯的確會(huì)破壞活性細(xì)胞功能。為了找出其中的原因，Kane還邀請(qǐng)工程系教授高華健(Huajian Gao)加入這一研究團(tuán)隊(duì)，以期為石墨烯材料與活性細(xì)胞的互動(dòng)關(guān)系建立詳細(xì)的電腦模擬圖。 該研究團(tuán)隊(duì)是在偶然間發(fā)現(xiàn)這樣的結(jié)果，因?yàn)樗麄円婚_始模擬石墨烯與活細(xì)胞間互動(dòng)關(guān)系所顯示的結(jié)果是良性的。然而，Kane的生物小組經(jīng)由過去的毒性實(shí)驗(yàn)結(jié)果已經(jīng)知道石墨碎片事實(shí)上會(huì)干擾到活細(xì)胞的正常功能。后來才發(fā)現(xiàn)，原來第一代模擬過于簡(jiǎn)單，將石墨烯碎片建模為正方形，而現(xiàn)實(shí)世界中的石墨碎片邊緣鋒利邊角尖銳，可穿透細(xì)胞壁并吸附其余的碎片。經(jīng)過高華健教授修改模擬后成功為Kane的毒性實(shí)驗(yàn)重新進(jìn)行建模。

石墨烯(G)碎片邊緣尖銳，易穿透細(xì)胞薄膜
Source：Kane Lab / Brown UniversityzPresmc

經(jīng)過修正模擬后發(fā)現(xiàn)了石墨烯將干擾細(xì)胞正常功能的機(jī)制，布朗大學(xué)病理學(xué)和實(shí)驗(yàn)室醫(yī)學(xué)教授Annette von dem Bussche就能透過顯示細(xì)胞受干擾的詳細(xì)影像，重覆進(jìn)行毒性實(shí)驗(yàn)。后續(xù)的研究將針對(duì)人類的肺、皮膚與免疫細(xì)胞在培養(yǎng)皿中進(jìn)行實(shí)驗(yàn)，以確定石墨烯薄層是否會(huì)穿透活性細(xì)胞并且被吞噬。 所有令人感興趣的納米材料都具有獨(dú)特的性能，因此，盡管宣稱具有危險(xiǎn)性但也不致于影響其材料應(yīng)用，而且也有許多有毒的材料仍成功地用于半導(dǎo)體制造中，例如鉛、汞與鎘等。事實(shí)上，布朗大學(xué)的研究人員們還針對(duì)多種納米材料進(jìn)行毒性研究，以期作為開發(fā)更安全制造與處理方法的先決條件，以便在整個(gè)生命周期都能善加利用。 “納米材料最佳之處在于你可為其進(jìn)行建構(gòu)，使其具有所需的特定性能?！盞anes說，“因此，我們可以透過計(jì)算建模的方式，為這些材料進(jìn)行修改，使其毒性降低?！? 石墨烯一直被視為一種具有發(fā)展前景的新式材料，可望取代硅晶用于未來的半導(dǎo)體中。 本文授權(quán)編譯自EE Times，版權(quán)所有，謝絕轉(zhuǎn)載 編譯：Susan Hong 參考英文原文：Graphene Said to Pose Health Hazard，by R. Colin Johnson

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{pagination} Graphene Said to Pose Health Hazard R. Colin Johnson PORTLAND, Ore. — A team of researchers at Brown University has concluded that graphene -- the darling material of semiconductor futurists -- disrupts functions of living cells. If the results of the Brown toxicity study are confirmed by others, graphene could end up in the same hazardous-material category as its cylindrical relatives, carbon nanotubes. "Graphene is easier to produce than carbon nanotubes and can replace them in many applications," Agnes Kane, a professor at Brown, told me: Graphene has many unique features, but most important is that it is often manufactured from graphite -- a naturally occurring mineral -- by chemical or mechanical exfoliation, which separates the carbon layers, resulting in dry powders with the potential for inhalation exposure. As a pathologist, we have studied nanotubes and other related carbon materials, but this is the first two-dimensional nanomaterial we've tested for toxicity. The Brown research team led by Kane, chair of the school's Department of Pathology and Laboratory Medicine, began with toxicity studies of graphene, which showed that indeed it did disrupt cell functions as nanotubes do. To discover why, Kane recruited a colleague in engineering for her team, professor Huajian Gao, who created atomically detailed computer simulations of the graphene material interacting with a living cell. The mechanism discovered by the team was unexpected, since initial simulations of graphene interacting with living cells indicated it was benign. However, Kane's biology group knew from toxicity experiments that graphene fragments did, in fact, interfere with normal functions in living cells. It turned out that first-generation simulations were too simple, modeling graphene fragments as squares, whereas real-world graphene fragments have sharp, pointy edges that can penetrate cell walls drawing the rest of the fragment inside after it. Gao's revised simulations successfully modeled Kane's toxicity experiments. The sharp bottom corner of a piece of graphene (G) penetrating a cell membrane due to its nanoscale rough edges and sharp corners (scale bar is two microns). (Source: Kane Lab / Brown University) After the simulations revealed the mechanism by which graphene was interfering with normal cell function, Annette von dem Bussche, a professor of pathology and laboratory medicine, was able to repeat the toxicity experiments with detailed images that showed how the cells were being disrupted (see photo). The follow-up studies were performed on human lung, skin, and immune cells in Petri dishes, and confirmed that graphene sheets as large as 10 microns can pierce and be swallowed up by living cells. All interesting nanomaterials have peculiar properties, and being declared hazardous does not doom a material, since many hazardous materials are already successfully used in semiconductor manufacturing, including lead, mercury, and cadmium. In fact, the Brown researchers are investigating a variety of nanomaterials for toxicity, as a prelude to developing safer methods of manufacturing, handling, and utilizing them throughout their lifecycles. "The great thing about nanomaterials is that you can engineer them to have specific desirable properties," said Kane. "Using computational modeling, we hope to modify these materials to make them less toxic." Graphene is considered a promising candidate to replace silicon in future semiconductors. Funding for the Brown research was provided by the National Science Foundation and the National Institute of Environmental Health Sciences. Robert Hurt, a professor of engineering, and doctoral candidates Yinfeng Li (now a professor at Shanghai Jiao Tong University), Hongyan Yuan, and Megan Creighton also contributed to the work.