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博主胡德良:邢台学院外语系英语教授,中国译协专家会员,河北省译协常务理事,邢台市译协副会长。爱好翻译,内容涉及宇宙探秘、医疗卫生、家庭保健、生命科学、能源科学、地球科学、环境科学、散文小说和纪实文学等领域。所译文章曾见于《光明日报》、《科技日报》、《健康时报》、《健康报》、《英语世界》、《英语知识》、《科技英语学习》、《科学之友》、《科学与文化》、《世界科学》、《生命世界》等全国各大报刊。博客特色:英汉对照、图文并茂,融趣味性、科学性、知识性为一体。

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如何将聚合物的应用推向新领域(图)   

2017-05-21 08:52:45|  分类: 尖端科技 |  标签: |举报 |字号 订阅

  下载LOFTER 我的照片书  |
如何将聚合物的应用推向新领域(图) - 月亮飞船 - 欢迎光临月亮飞船的博客
 供图:尼克·斯宾塞(Nik Spencer/《自然》杂志
如何将聚合物的应用推向新领域(图) - 月亮飞船 - 欢迎光临月亮飞船的博客
 供图:史蒂夫·克施迈斯内尔(Steve Gschmeissner/SPL
化学剥脱术:为了制作2D聚合物薄膜,化学家们首先诱导单体形成3D晶体,然后以蓝光照射,使处于同一平面的单体连接起来,这样他们就能够一次剥下一张了。
The plastics revolution: how chemists are pushing polymers to new limits

如何将聚合物的应用推向新领域

Polymers have infiltrated almost every aspect of modern life. Now researchers are working on next-generation forms.
聚合物已经渗透到现代生活的方方面面。现在,研究人员正在研究下一代聚合物的形式。
胡德良   译

 Hermann Staudinger was a pacifist, but this was one fight he was determined to win. In 1920, the German chemist proposed that polymers — a broad class of compounds that included rubber and cellulose — were made of long chains of identical small molecules linked by strong chemical bonds1. Most of his colleagues thought this was arrant nonsense, and argued that polymers were merely looser aggregations of small molecules. Staudinger refused to back down, sparking feuds that spanned a decade.

 赫尔曼·施陶丁格是一位和平主义者,但是对于这一战他是决心要赢。1920年,这位德国化学家提出:聚合物是包括橡胶和纤维素在内的一大类化合物,是由完全相同的长串小分子组成的,这些小分子由强劲的化学键连接起来。施陶丁格的多数同事们认为,他所说的完全是无稽之谈;他们争辩说,聚合物只不过是小分子比较松散地聚集在一起。施陶丁格不肯让步,引发了一场跨越十年的论战。

 Eventually, laboratory data proved that he was right. He won the 1953 Nobel Prize in Chemistry for his work, and synthetic polymers are now ubiquitous: last year, the world produced about 300 million tonnes of them. The molecular chains that Staudinger hypothesized have entered almost every aspect of modern life, from clothes, paint and packaging to drug delivery, 3D printing and self-healing materials. Polymer-based composites even make up half the weight of Boeing’s most recent passenger aeroplane, the 787 Dreamliner.

 最终,实验室数据证明施陶丁格是正确的。由于出色的研究工作,施陶丁格获得了1953年诺贝尔化学奖。现在,合成聚合物无处不在——去年,全世界生产了大约3亿吨合成聚合物。从服装、油漆和包装材料到3D打印、药物输送和自愈合材料,施陶丁格假设中的分子链几乎已经进入现代生活的方方面面。甚至在波音公司最新客机——878梦幻客机中,有一半的重量是由聚合物基复合材料构成的。

 So where will polymers go next? Some answers will come this week, when a once-per-decade workshop organized by the US National Science Foundation attempts to survey which new areas are emerging.

 那么,聚合物下一步的目标是什么呢?对此,本周将会得到一些答案。美国国家科学基金会将要于本周组织十年一度的专题研讨会,试图调查聚合物将会出现在哪些新的应用领域。

 “The general trend — still continuing — is the expansion of polymers into applications that have not been traditionally theirs,” says Tim Lodge, a polymer chemist at the University of Minnesota in Minneapolis and editor of the journal Macromolecules. That expansion has been driven by advances in every aspect of polymer science, he says. Researchers have developed new methods to synthesize and analyse molecules, improved theoretical models and created mimics of polymers found in nature. At the same time, says Lodge, attitudes to the science have changed. No longer do universities dismiss polymer science as too dirty, practical and industrial for academia. “Just about every chemistry department has someone doing polymer stuff now,” he says, and frontier work on polymers is increasingly interdisciplinary.

 明尼苏达大学明尼阿波利斯分校高分子化学家兼《大分子》杂志社编辑蒂姆·洛奇说:“总的趋势是,聚合物的应用扩展到传统上不属于这个领域的方面,而且这个趋势仍在继续。”洛奇称:这种应用的扩展是由聚合物科学在各个领域的发展所推动的。研究人员开辟了合成和分解分子的新方法,改进了理论模型,创造了天然聚合物的仿制品。洛奇说:人们对待这门科学的态度也发生了改变。大学不再认为,聚合物科学对于学术界来讲太讨厌、太实际、太具产业性。洛奇说:“现在,几乎每个化学部门都有人在研究聚合物材料,而且聚合物领域前沿的研究工作越来越具有跨学科的性质。”

 It will need to be. Researchers have a growing toolbox of techniques with which to craft the chemical architecture of polymer strands, but they are often unable to predict whether the resulting compound will have the particular properties needed for, say, a membrane or a drug-delivery system. Meeting that challenge will demand a much deeper understanding of how the chemical structure of a polymer determines its physical properties, at every scale from nanometres to metres.

 聚合物领域需要跨学科。研究人员的技术工具越来越多,用来创建聚合物链的化学构筑,但是对于形成的化合物,他们常常无法预见是否拥有所需要的特性,比如一张薄膜或一种药物输送机制。要想应对这一挑战,就需要从纳米到米的任何尺度上对于聚合物的化学结构如何决定其物理性质有一个更加深刻的理解。

 Polymers forever

 永远的聚合物

 Polymers are everywhere — and therein lies the problem. “Most polymers we use in everyday life are from petroleum-based products, and although they’re durable in use, they’re also durable in waste,” says Marc Hillmyer, director of the Center for Sustainable Polymers (CSP) at the University of Minnesota. An estimated 86% of all plastic packaging is used only once before it is discarded2, producing a stream of waste that persists in waterways and landfill, releases pollutants and harms wildlife.

 聚合物到处都有——这也是问题所在。明尼苏达大学可持续聚合物研究中心主任马克·希尔姆耶说:“我们日常生活中运用的多数聚合物来自石油产品,尽管这种聚合物经久耐用,但是成为废品后也久久不能降解。”据估计,所有的塑料包装材料中有86%只用一次,然后就被抛弃,产生了大量的废弃物,长久地处于水路和垃圾填埋场中,释放污染成分,危害野生动植物。

 Many biodegradable carriers bags are made from polylactic acid, a polymer derived from plant starch (green).

 许多可生物降解的手提袋是由聚乳酸制成的,聚乳酸是一种来自植物淀粉的绿色聚合物。

 That is why the past decade has seen an explosion of interest in polymers that are made from renewable resources and biodegrade easily and harmlessly. Polymers based on natural starch are already on the market; so too is synthetic polylactide (PLA), which is made from lactide or lactic acid derived from biological sources, and which is found in products from tea bags to medical implants.

 这就是在过去十年中对新型聚合物兴趣大增的原因,这些聚合物是由可再生资源制造的,易于生物降解,不会造成危害。基于天然淀粉的聚合物已经上市,合成聚乳酸(PLA)也已经上市。合成聚乳酸是由来源于生物的丙交酯或乳酸制成的,从茶袋到医疗植入物等产品中都有所应用。

 But sustainable polymers still make up less than 10% of the total plastics market, says Hillmyer. One hurdle is that they cost too much. Another is that the monomer building blocks of natural polymers tend to contain more oxygen atoms than are found in the fossil hydrocarbons of petroleum. This affects the polymers’ properties — stiffening the materials, for example — which can make it difficult for them to directly replace cheap and flexible plastics such as polyethylene and poly?propylene. Turning natural polymers into exact molecular matches for conventional ones takes some sophisticated chemistry.

 但是,希尔姆耶称:在市场中,可持续聚合物在整个塑料产品中只占不到10%。一个障碍就是,代价太高。另一个障碍是,天然聚合物的单体基础材料所包含的氧原子比石油中的化石碳氢化合物更多。这就影响了聚合物的属性,例如:会使这种材料变硬,因此使其难以直接替代像聚乙烯和聚丙烯这样既便宜又柔软塑料产品。要使天然聚合物在分子上完全匹配传统聚合物,还需要一些复杂的化学变化。

 One alternative approach is to beef up sustainable polymers such as PLA by blending them with conventional polymers. This route typically has downsides, such as rendering some plastics less transparent. But CSP researchers have got around that problem by adding just 5% by weight of a low-cost, petroleum-derived polymer that contains some sections that are hydrophobic — water-insoluble — and others that are hydrophilic, or water-soluble. These additives cluster together to create spherical structures, which render PLA substantially tougher without reducing its transparency.

 一个可替代的办法就是,掺进传统的聚合物,提高合成聚乳酸等可持续聚合物的质量。这种办法通常会有不足之处:如,使一些塑料变得透明度较差。但是,可持续聚合物研究中心的研究人员避免了这个问题:按重量计算,仅仅加入5%来自石油的廉价聚合物便可,其中有些部分是疏水的,具有水不溶性,其余部分是亲水的,具有水溶性。这些添加剂聚集在一起,产生了球形结构,在不降低透明度的情况下使合成聚乳酸的韧性大大提高。

 Hillmyer’s team has also made a partially recyclable form of polyurethane foam, which is found in a host of products, including insulation, seat cushions and gaskets. The recipe for this polyurethane includes a low-cost poly?mer called poly(β-methyl-δ-valerolactone) (PMVL), based on monomers made by modified bacteria. Heating the foam to above 200?°C breaks down the polyurethane so that the monomers can be extracted and used again.

 从某种程度上说,希尔姆耶的团队还制造了一种可回收利用的聚氨酯泡沫,这种泡沫可用于大量的产品中,包括隔热产品、坐垫和密封垫。这种聚氨酯的配方中包括一种叫做聚(β-甲基-δ-戊内酯)(PMVL)的廉价聚合物,该聚合物是以改性细菌制成的单体为基础的。将这种泡沫加热至200?°C以上,分解掉聚氨酯,这样其中的单体就可以提取出来,再次利用。

 It remains to be seen whether these sustainable polymers can be commercialized. “Often the biggest challenge is to do it at scale, which requires favourable economics,” says Hillmyer. He thinks the field needs to establish general design rules that predict how a monomer’s chemical structure affects the rate, temperature and yield of polymerization reactions, and how the resulting polymers will interact with other materials. His team has developed such guidelines for PMVL’s constituents, and last year formed a spin-off company at the CSP called Valerian Materials to exploit these principles.

 能否将这些可持续聚合物加以商业化推广呢?这一点仍有待观察。希尔姆耶称:“通常情况下,最大的挑战就是进行大规模地生产,但是要想做到这一点就需要具有良好的经济状况。”他认为,这个领域需要建立一套通用的设计规则,用以预测一个单体的化学结构如何影响聚合反应的速度、温度和发生,预测形成的聚合物将会如何跟其他材料发生相互作用。希尔姆耶的研究小组为PMVL的委托方创建了设计指导原则,为了开发利用这些原则,研究小组去年在可持续聚合物研究中心成立了一家衍生公司,名为瓦勒良材料公司

 Some researchers are pursuing another trick: rather than stringing together bioderived monomers, they are learning to use natural polymers directly. Cellulose, for example, consists of glucose molecules strung together into chains, which in turn line up to form strong fibres, or fibrils, that make up the stiff cell walls of plants. In many places, the cellulose chains form crystalline chunks that are up to 20?nanometres wide and hundreds of nano?metres long, and that can be chemically extracted from cellulose pulp. Proponents say that these crystals could be used for applications such as strengthening composites, forming insulating foams, delivering drugs and providing a scaffold for tissue repair.

 一些研究人员正在研究另一种技术:他们并不是把生物衍生的单体连接起来,而是学会直接利用天然聚合物。例如,纤维素是由连接成链的葡萄糖分子组成的,这些链又排列起来形成强有力的纤维,这种纤维构成了植物的坚硬细胞壁。在许多情况下,纤维素链形成的结晶块达20纳米宽,数百纳米长,可以通过化学手段从纤维素浆粕中提取。支持这一技术的人员说:这些晶体可以应用在诸如强化复合材料、形成隔热泡沫、输送药物、为组织修复提供支架等领域。

 Cellulose nanocrystals and longer nano?fibrils are now produced on a commercial scale, but the commercial applications do not yet go much beyond stiffening paper or thickening fluids. Christoph Weder, director of the Adolphe Merkle Institute for nanoscience at the University of Fribourg in Switzerland, says that it will take a lot more work to reduce costs and demonstrate unique advantages for sustainable polymers. “We really need a road map for biobased polymers,” he says.

 纤维素纳米晶体和较长的纳米纤维现在已经投入了商业规模的生产,但是其商业应用还没有大大超出使纸张变硬和使流体变稠的范围。瑞士弗里堡大学阿道夫默克尔研究所纳米科学部主任克里斯托夫·韦德称:为了降低成本,并展示可持续聚合物的独特优势,我们还需要进行更多的研究工作。他说:“对于生物基聚合物,我们迫切需要一种方向性的引导。”

 Skin in the game

 利益共享

 In a mixed-up world, polymers can restore some order. Polymer membranes already serve asmolecular sieves for separating gases, de?salinating seawater and keeping molecules apart inside fuel cells. But they could have a much bigger impact in the future, says Lodge. “There are so many problems that could be solved by better membranes.”

 在一个物质混杂的世界中,聚合物在某种程度上可以使其恢复条理性。聚合物薄膜已经被用作分子筛,来分离气体、淡化海水、保持燃料电池内部的分子处于分离状态。但是,洛奇说:聚合物薄膜对未来的影响可能要大得多,“许多问题都有可能通过质量更好的薄膜来解决。”

 Separating mixtures with membranes takes a lot less energy than does distillation, in which a liquid is heated to evaporate its components at different temperatures. It also requires much less space than using scrubbers, devices in which pollutants are trapped by chemical reactions. Membranes made from polymers are not only cheap to make at large scale, but can cover large areas without acquiring structural defects that let the wrong molecules pass through.

 跟蒸馏相比,利用薄膜来分离混合物耗费的能量要少得多。蒸馏就是给一种液体加热,利用不同的温度将不同的成分蒸发。跟利用洗涤器相比,利用薄膜所占用的空间也要小得多,况且洗涤器中往往会由于化学反应而积聚污染物。通过聚合物制造的薄膜不仅便宜,适于大规模生产,而且覆盖面积大,不会产生放过错误分子的结构缺陷。

 Gas-separation membranes are already used industrially to tease hydrogen and carbon dioxide from natural gas. But improved membranes could tackle harder tasks, such as distinguishing between the very similar hydrocarbons propane and propene. Tougher, chemically robust membranes could operate at higher temperatures to remove carbon dioxide from hot flue gases.

 在工业上,气体分离薄膜已经被用来将氢和二氧化碳从大气中分离出来。但是,改良的薄膜或许能够解决更加艰难的任务,例如:把极为相似的烃类气体——丙烷和丙烯分离。更加艰难的是,化学性质稳定的薄膜也许能够在较高的温度下运行,将二氧化碳从热烟道气中提取出来。

 Membrane chemist Benny Freeman of the University of Texas at Austin is hoping to improve the treatment of waste water from gas fracking operations, in which water is forced into rock to split it open and release natural gas. After use, the water is so dirty that standard filtration membranes quickly get clogged, so the water must be put under high pressure to push it through, and the membranes must be cleaned with chemicals that shorten their lifespan. But Freeman has found a way to sidestep that problem by giving the membranes a gossamer-thin coating of polydopamine, which mimics the waterproof glue used by mussels to cling onto rocks. Piloted at a fracking water-treatment facility near Fort Worth, Texas, the polydopamine coating halved the pressure needed to push water through the membrane, which could result in smaller, more efficient treatment systems7. The team has already used these membranes to build units for the US Navy, so that ships can purify oily bilge water before dumping it.

 得克萨斯大学奥斯汀分校薄膜化学家班尼·弗里曼希望能够提高水平,处理来自气体压裂作业的废水。在气体压裂过程中,为水施压,让水进入岩石中,致其开裂,然后释放出天然气。水用过之后变得很脏,标准的过滤膜很快就会堵塞,因此必须对水施以高压来推进水的通过,可是这种薄膜必须要用化学药品来进行清洁,而化学药品会缩短薄膜的寿命。但是,弗里曼发现了避免这一问题的办法:为这些薄膜涂上薄薄的一层聚多巴胺,这样聚多巴胺就模仿了紧贴在岩石上的蚌类所利用的防水胶。在德克萨斯州沃思堡附近一套压裂水处理设施中做试验时,聚多巴胺涂层将水通过薄膜时所需的压力减半,这样就可以制造出体积更小、更加高效的处理系统。该研究小组已经利用这些薄膜为海军部队制造设备,使船舶能够将含油舱底水净化之后再放进海洋中。

 In December 2015, the US presidential administration launched a ‘moonshot for water’ to boost water sustainability, and as part of that effort the US Department of Energy plans to establish a desalination-research hub in 2017. Polymer membranes will have a big role in that effort, says Freeman. “We’re slated to see a huge increase in efforts to expand the use of polymers in that space.”

 201512月,美国总统政府推出了一项“登月寻水”计划,以促进水资源的可持续发展。作为该计划的一部分,美国能源部计划在2017年建立一个海水淡化研究中心。弗里曼说:在这一计划中,聚合物薄膜将会起到重大的作用,“在努力推进聚合物应用于太空的过程中,我们定会发现聚合物大有用武之地。”

 To design better desalination membranes, researchers will need to be able to predict how factors such as the distribution of charged chemical groups in a polymer affects its permeability to ions. Earlier this year, Freeman and his colleagues published what he believes is the first model to do just that, which could enable chemists to build particular properties into a membrane by tailoring its chemical substituents and cross-linking the molecules. “I’m on a mission to get people to ask these kinds of questions about structure–property relations, which could really guide synthesis,” he says.

 为了设计出性能更好的脱盐薄膜,研究人员要能够预测一种聚合物中带电化学基团的分布等因素如何影响该聚合物对离子的渗透性。今年早些时候,弗里曼及同事发布了一项成果,弗里曼认为这项成果就是能够进行上述预测的首个模型,该模型能够使化学家们通过调整化学取代基并通过交联分子将特定的性能融入一种薄膜中。弗里曼说:“我的任务是,让人们对有关结构与性能关系的这些问题感到好奇,这种关系对合成材料能够真正地起到指导作用。”

 The ultimate separation membrane could be just one molecule thick. These 2D polymers are surfing the wave of enthusiasm for single-layer materials that followed the isolation of graphene just over a decade ago.

 最终的分离薄膜可能只有一个分子的厚度。分离出石墨烯之后刚刚过了十年,这些2D聚合物就在追求单层材料的热潮中诞生了。

 The flat polymers are not just very thin films of ordinary, linear polymers. Instead, they have an intrinsically 2D chemical structure that looks like a fishing net, with a regular, repeating mesh full of molecule-size openings. They can also carry a wide variety of chemical decorations on their surfaces, so that each opening can be precisely engineered to allow certain molecules through and bar others.

 这些平整的聚合物不仅仅是非常薄的普通层叠状线型聚合物,相反,它们从本质上来讲是一种二维化学结构,看起来像渔网,有着规则的、重复的网孔状区域,网孔状区域中充满了分子大小的开口。这种聚合物表面可以携带各种各样的化学修饰,使每个开口都可以得到精确设计,以便允许某些分子通过,而阻拦其余的分子。

 But creating 2D polymers is tough. If just one of the holes in the growing mesh closes up in the wrong way, the membrane could buckle into a 3D mess. Polymer chemist Dieter Schlüter of the Swiss Federal Institute of Technology in Zurich worked on this problem for more than a decade before achieving success in 2014.

 然而,创造2D聚合物是艰难的——如果变化中的网状区域只有一个开口闭合的方式有误,那么薄膜就会扭曲成一团糟。瑞士联邦理工学院高分子化学家迪特尔·施律特研究这个问题十多年,于2014年获得成功。

 His approach relies on coaxing carefully designed monomers to form a crystal. A blast of blue light then triggers a chemical reaction between monomers in the same plane, creating a new crystal made up of stacked polymer layers. These can be peeled off to give individual 2D sheets just one monomer thick (see ‘Chemical peel’).

 施律特的方法靠的是,诱导精心设计的单体,使其形成晶体。然后,用一束蓝光致使同一平面内的单体之间发生化学反应,形成一种由层叠状聚合物层构成的新晶体。这些聚合物层可以被剥离成单张的二维膜片,厚度只有1纳米(见上图:化学剥脱术)。

 Using the same approach, Schlüter and Benjamin King, head of the chemistry department at the University of Nevada, Reno, have independently produced different types of 2D polymer910. Now collaborators, the two researchers hope that they will soon be able to make these sheets in kilogram batches, easily enough to distribute samples to research groups around the world.

 利用同样的方法,施律特和内华达大学里诺分校化学系主任本杰明·金各自独立创造出不同类型的2D聚合物。现在,这两位研究人员成为合作伙伴,他们希望不久能够利用这样的方法制成一公斤一组的膜片,很容易地将样品分发到世界各地的研究团体中。

 Schlüter admits that he has faced scepticism about whether 2D polymers will flourish. “But that’s healthy,” he says. “And I’m very stubborn — I will not give up, I’m convinced of the great potential this development has.”

 施律特承认,在2D聚合物是否能够蓬勃发展起来这个问题上,有人对他持有怀疑态度。“但这是没有问题的。”他说,“我这个人非常固执——我不会放弃的,我相信这个领域的发展有着巨大的潜力。”

 Boutique polymers

 精品聚合物

 Widely used polymers such as polystyrene and polyethylene are spectacularly boring in one sense: they repeat the same monomer over and over again. Their one-note tune is especially monotonous when compared with the quadraphonic symphony of DNA, which encodes an entire genome with 4 monomers; or the baroque masterpiece of a protein, drawing from 23 amino acids to build a complex 3D structure.

 从某种意义上来说,像聚苯乙烯和聚乙烯之类广泛应用的聚合物是非常单调的:它们一遍又一遍地重复着相同的单体。它们犹如单音符曲调,跟相当于四声道交响曲的DNA相比或者跟像巴洛克杰作一样的蛋白质相比,显得尤为单调。DNA利用四个单体编制成一个完整的基因组;蛋白质通过23个氨基酸构建成一个复杂的三维结构。

 One of the most challenging frontiers of polymer research is to tailor synthetic polymers with the same precision, so that chemists can fine-tune the electronic and physical properties of their products. “It’s become very fashionable in the past five years,” says Jean-Fran?ois Lutz, a macromolecular chemist at the University of Strasbourg in France. Sequence-controlled polymers would contain monomers in a predetermined order, forming strands of a very specific length.

 聚合物研究最具挑战性的问题之一是以同样的精度定制合成聚合物,使化学家们能够对产品的电子特性和物理特性进行微调。法国斯特拉斯堡大学大分子化学家让-弗朗索瓦·鲁兹说:“在过去的五年中,这一领域的研究变得非常时尚。”顺序控制的聚合物中包含的单体是按预定顺序排列的,所形成的链具有非常具体的长度。

 Last year, a team led by Jeremiah Johnson, a chemist at the Massachusetts Institute of Technology in Cambridge, showed11 that they could achieve that kind of control through iterative exponential growth — first uniting two different monomers to make a dimer, then connecting two dimers to make a tetramer, and so on. Modifying each monomer’s chemical side-chains between cycles adds complexity, and a semi-automated system can make the process less laborious.

 去年,剑桥市麻省理工学院化学家耶利米·约翰逊领导的一个团队证实:通过迭代指数增长,他们能够获得顺序控制——首先将两种不同的单体联合成二聚体,然后将两个二聚体连接成四聚体,以此类推。修改循环周期之间每个单体的化学侧链就会增加复杂性,一种半自动系统能够使这个过程更加省力。

 Johnson is now studying how his sequence-controlled polymers might be used in drug delivery. A dozen drugs approved by the US Food and Drug Administration use a polymer called polyethylene glycol to shield them from the body’s immune system, improve their solubility or prolong their time in the body. Johnson says that a sequence-controlled polymer could provide a more predictable biological effect, because every strand would be the same length and shape, and its chemistry could be carefully designed to assist its drug cargo in the most useful way.

 目前,约翰逊正在研究他的顺序控制聚合物如何用来输送药物。美国食品和药物管理局审批通过的十几种药物利用一种叫做聚乙二醇的聚合物来保护药物不受身体免疫系统的影响,提高药物的溶解度或延长药物留在体内的时间。约翰逊说:一种顺序控制的聚合物能够提供更具可预测性的生物效果,因为每个链的长度和形状都是一样的,其化学性质可以经过精心设计,以最为有益的方式协助药物发挥作用。

 Sequence-controlled polymers could also store data in a more compact and inexpensive form than can conventional semiconductor technology, with each monomer representing a single bit of information. Last year, Lutz demonstrated a key step towards that goal. He used two types of monomer to represent digital 1s or 0s, and a third to act as a spacer between them. The monomers contained chemical groups that allowed them to connect only to the growing polymer, rather than reacting with each other randomly. The string of 1s and 0s could be read by watching how the polymer broke apart inside a mass spectrometer.

 跟传统的半导体技术相比,顺序控制的聚合物也可以以更加轻便的方式存储数据,成本也会更低,每个单体代表信息的一个比特。去年,鲁兹证明了实现该目标的一个关键环节。他利用两种单体分别代表数字1和数字0,利用第三种单体充当两者之间的间隔段,间隔段仅仅用来连接不断增加的单体,而不是随意地在相互之间发生反应。通过观察这种聚合物在质谱仪里的分裂方式,就可以读取这一连串的10

 Earlier this month, Lutz showed that a library of different polymer strands could encode a 32-bit message. That pales by comparison with the 1.6?gigabits that have been stored in artificial DNA molecules (see go.nature.com/2b2ve0u). But momentum is growing for polymer data storage. In April, the Intelligence Advanced Research Projects Activity (IARPA), a US agency that funds high-risk research for the intelligence community, drew representatives from the biotechnology, semiconductor and software industries to a workshop on the subject. “There’s a vibrant and growing community of researchers working on this,” says David Markowitz, a technical adviser at IARPA who helped to organize the workshop.

 本月早些时候,鲁兹证明了一组不同的聚合物链可以编制一条32比特的信息。跟人工DNA分子中存储1.6吉比特的信息相比,还是相形见绌的。但是,聚合物数据存储的势头与日俱增。4月份,美国行政机构——情报高级研究计划局(IARPA)为情报界的高风险研究提供资助,吸引了来自生物技术、半导体、软件行业的代表参加了有关该主题的一个研讨会。IARPA技术顾问大卫·马科维茨为组织研讨会提供了帮助,他说:“研究这个主题的研究人员充满活力,所涉及的学术界范围也越来越广。”

 But the approach still faces enormous technical challenges: current synthetic techniques are much too slow and expensive. The key to cracking the data-storage problem — and many other problems at the polymer frontier — will be to develop better ways to predict the properties of polymers and fine-tune their production. That will require a concerted effort. “We need to establish collaborations with physicists, materials scientists, theoretical chemists,” says Lutz. “We need to build a new field.

 但是,这种存储方法仍然面临着严峻的技术挑战:目前,合成技术过于缓慢、过于昂贵。解决数据存储问题以及聚合物前沿领域许多其他问题的关键将是,找出更好的办法来预测聚合物的特性,并对聚合物的生产过程进行微调。这就需要共同努力。“我们需要跟物理学家、材料科学家、理论化学家建立合作关系。”鲁兹说,“我们需要创建一个新的领域。”

   
译自:英国《自然》杂志官网(17 August 2016
原著:Mark Peplow(马克·佩普洛)
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