新高级阅读前（双语）47（1128）

PASSAGE FORTY-SEVEN

Drug injury

1.Medical drugs sometimes cause more damage than they cure. One solution to this problem is to put the drugs inside a capsule, protecting them from the body—and the body from them—until they can be released at just the right spot.

2.There are lots of ways to trigger this release, including changing temperature, acidity, and so on.

3.But triggers can come with their own risks—burns, for example. Now, researchers in California have designed what could be a harmless trigger to date: shining near-infrared light (NIR) on the drug in the capsule.

4.The idea of using light to liberate the drug in the capsule isn’t new. Researchers around the globe have developed polymers and other materials that begin to break down when they absorb either ultraviolet (UV) or visible light.

5.But tissues also readily absorb UV and visible light, which means the drug release can be triggered only near the skin, where the light can reach the capsule.

6.NIR light largely passes through tissues, so researchers have tried to use it as a trigger. But few compounds absorb NIR well and go through chemical changes.

7.That changed last year when Adah Almutairi, a chemist at the University of California, San Diego, reported that she and her colleagues had designed a polymer that breaks down when it absorbs NIR light.

8.Their polymer used a commercially available NIR-absorbing group called o-nitrobenzyl (ONB).

9.When they catch the light, ONB groups fall off the polymer, leading to its breakdown. But ONB is only a so-so NIR absorber, and it could be poisonous to cells when it separates from the polymer.

10.So Almutairi and her colleagues reported creating a new material for capsules that’s even better. This one consists of a long chain of compounds called cresol groups linked in a polymer.

11.Cresol contains reactive components that make it highly unstable in its polymeric form, a feature Almutairi and her colleagues use to their advantage.

12.After polymerizing the cresols, they cap each reactive component with a light-absorbing compound called Bhc. When the Bhc absorb NIR light, the reactive groups are exposed and break the long polymer into two short chains.

13.Shining additional light continues this breakdown, potentially releasing any drugs in the capsule.

14.What’s more, Almutairi says, Bhc is 10 times better at absorbing NIR than is ONB and is not poisonous to cells.

第四十七篇

药物伤害

1.药物有时造成的伤害比治愈的还要多。解决这个问题的一个办法是把药物放在胶囊里，保护它们不被身体接触，也保护身体不被它们接触，直到它们能在合适的位置释放出来。

2.触发这种释放的方法有很多，包括改变温度、酸度等。

3.但触发因素也会带来风险，比如燃烧风险。现在，加利福尼亚的研究人员已经设计出一种迄今为止无害的触发方法:用近红外光(NIR)照射胶囊中的药物。

4.利用光来释放胶囊中的药物的想法并不新鲜。世界各地的研究人员已经开发出聚合物和其他材料，当它们吸收紫外线或可见光时就会开始分解。

5.但组织也很容易吸收紫外线和可见光，这意味着药物释放只能在皮肤附近触发，在那里光线可以到达胶囊。

6.近红外光主要穿过组织，因此研究人员试图将其作为触发因素。但很少有化合物能很好地吸收近红外并发生化学变化。

7.去年，加州大学圣地亚哥分校的化学家阿达·阿尔穆塔瑞报告说，她和她的同事设计了一种聚合物，这种聚合物在吸收近红外光时会分解。

8.他们的聚合物使用了一种市售的nir吸收基团，邻硝基苄基(ONB)。

9.当它们捕捉到光时，ONB基团从聚合物上脱落，导致其分解。但是ONB只是一个一般的近红外吸收剂，当它从聚合物中分离出来时可能对细胞有毒。

10.因此，阿尔穆塔瑞和她的同事报告说，他们创造了一种更好的胶囊新材料。它由一长链化合物组成，叫做甲酚基团，它们以聚合物的形式连接在一起。

11.甲酚含有活性成分，使其在聚合形式下非常不稳定，阿尔穆塔瑞和她的同事利用了这一特点。

12.在甲酚聚合后，他们用一种叫做Bhc的吸光化合物覆盖每个反应成分。当Bhc吸收近红外光时，反应基团暴露并将长聚合物分解成两条短链。

13.照射额外的光线会继续这种分解，可能会释放胶囊中的任何药物。

        14.更重要的是，阿尔穆塔瑞说，Bhc吸收近红外光谱的能力是ONB的10倍，而且对细胞无毒。