本文音频及原文摘自杂志The Economist 2016年第35期，Science and Technology版块。

Medical batteries

A bodily pigment may have industrial uses

Aug 27th 2016

SINCE their invention two centuries ago, batteries have been made from many things. The first were of copper and zinc[1铜锌(原电池)]. Today, lithium[锂] is preferred for a lot of applications. Lead[铅], nickel[镍], silver[银] and a host of other materials have also been used. Until recently though, no one had tried melanin[黑色素], the pigment[色素;颜料] that darkens skin and protects it against ultraviolet light[紫外线]. But, as he reported this week at a meeting of the American Chemical Society in Philadelphia[费城(美国宾夕法尼亚州东南部港市)], Christopher Bettinger of Carnegie Mellon University[卡耐基梅隆大学], in Pittsburgh[匹兹堡], has now done just that. His purpose is to create a battery safe for use in the human body.

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Melanin is not, at first sight, an obvious battery ingredient. It is a complicated molecule[分子;微小颗粒,微粒] composed of carbon[碳], oxygen[氧], nitrogen[氮] and hydrogen[氢]. To synthesise[2] it on an industrial scale[工业生产/工业规模] would surely require biotechnology rather than conventional chemistry. But it does have the ability to capture and release positively charged ions[正电离子], known as cations[阳离子]. Batteries depend on the movement of ions, so this property is a good start. On top of that, being a normal ingredient of bodies, melanin is not toxic[有毒的;中毒的]. This is in contrast to many conventional battery ingredients, including most of those listed above. If melanin were to leak out of[溢出] an implanted medical device[植入式医疗装置], it would simply be mopped up[3] by enzymes['enzaɪmz][酶类;酵素].

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The battery Dr Bettinger has come up with has a melanin[黑色素] cathode[(原电池的)正极;(电解池的)负极], an anode[(电解池的)正极;(原电池的)负极] of sodium titanium phosphate[磷酸钛钠], which is also non-toxic, and an aqueous electrolyte[含水电解质;水系电解液] that can be charged with any soluble cation[阳离子] desired. He has experimented with ions of sodium[钠], potassium[钾], rubidium[铷], caesium[铯], magnesium[镁], aluminium[铝] and iron[铁]. Most of the resulting batteries had modest voltages (between 0.5 and 0.7 volts) but stored enough energy to power one-shot ingestible devices[一次性可吸收装置] such as capsule endoscopes[胶囊内镜] (pill-shaped machines which can look at parts of the alimentary canal[消化道] that conventional endoscopy[常规内镜] cannot reach) or drug-delivery systems[给药系统;投药系统] designed to release their payloads[有效负载;酬载] at a particular place in the gut[消化道;肠道;肠].

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Intriguingly[in'tri:giŋli][有趣地;有魅力地], though the uses Dr Bettinger has in mind do not need a rechargeable battery[可再充电的电池], one of the experimental models his team produced—that containing magnesium[镁]—could be recharged. This goes against conventional wisdom[传统观点;世俗认知], for previous attempts to make a rechargeable magnesium battery have failed. Given the abundance and cheapness of magnesium, that may be useful information for battery engineers seeking to outdo[超过;胜过] modern lithium-ion[锂离子] batteries. If so, then melanin or something like it might find itself in very heavy demand indeed.

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[1]copper and zinc 铜锌(原电池)

想起了高中化学，上个图怀念一下...

[2]synthesize ['sɪnθəsaɪz]

to produce a substance by a chemical reaction in plants or animals 合成

There are many vitamins that the body cannot synthesize itself.

有很多维生素是人体自身无法合成的。

[3]mop up

1）If you mop up something that you think is undesirable or dangerous, you remove it or deal with it so that it is no longer a problem. 清除 (不合意或危险的事物)

2）to use a piece of cloth or a mop to remove liquid from the surface of something （用布或拖把）吸干净；用拖把擦去

There's milk on the floor over there - could you get a cloth and mop it up?

那边地板上有牛奶——你能拿块布把它擦干净吗？

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以上言论不代表本人立场。

原文摘自The economist，仅外语学习之用。

其中生词解释来源于Cambridge Dictionaries

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