新发现的牙釉质结构，可能最终解释了其奇异的强度

新发现的牙釉质结构，可能最终解释了其奇异的强度

A new, first-of-its-kind glimpse at the nanostructure of tooth enamel helps to explain why the hardest substance in the human body is so incredibly resilient.

对牙釉质纳米结构的首次研究,有助于解释为什么人体内最坚硬的物质具有如此难以置信的弹性。

Tooth enamel looks like bone, but it's not actually living tissue. This outer layer of the tooth – which encases and protects other tissue inside the tooth – forms when we are young, and once teeth are developed, it has no natural ability to self-repair or regrow.

牙釉质看起来像骨头，但实际上不是活组织。牙齿的外层——包围和保护牙齿内部的其他组织——是在我们年轻的时候形成的，一旦牙齿长出来，它就没有自我修复或再生的自然能力。

Luckily, the mineralisation process that produces tooth enamel creates an incredibly tough substance that is harder than steel, and new research reveals a never-before-seen mechanism that helps make its exceptional resilience possible.

幸运的是，产生牙釉质的矿化过程产生了一种难以置信的坚韧物质，这种物质比钢还硬。新的研究揭示了一种前所未见的机制，帮助牙釉质变得异常坚韧。

We apply huge pressure on tooth enamel every time we chew, hundreds of times a day, says biophysicist Pupa Gilbert from the University of Wisconsin-Madison.

来自威斯康星大学麦迪逊分校的生物物理学家Pupa Gilbert说:“我们每天咀嚼几百次，每次都对牙釉质产生巨大的压力。”

Tooth enamel is unique in that it has to last our entire lifetime. How does it prevent catastrophic failure?

“牙釉质是独一无二的，因为它要持续我们的一生。如何防止灾难性的失败?”

The answer lies in what the researchers call the "hidden structure" of tooth enamel: an infinitesimal structural arrangement of the nanocrystals that make up our outer layer of teeth.

答案在于研究人员所称的牙釉质的“隐藏结构”:构成我们牙齿外层的纳米晶体的一种极其微小的结构安排。

These extremely tiny crystals are made of a kind of calcium apatite called hydroxyapatite. The same mineral substance is found in the teeth of other creatures too, and the crystals really are small, measuring less than one thousandth the thickness of a human hair.

这些极其微小的晶体是由一种叫做羟基磷灰石的钙磷灰石构成的。在其他生物的牙齿中也发现了同样的矿物质，而且晶体确实很小，实际测量不到人类头发厚度的千分之一。

They're so small in fact, it's been difficult to get a good look at them before now.

它们实在太小了，以前很难看清它们。

Prior to this study, we just didn't have the methods to look at the structure of enamel, Gilbert says.

“在这项研究之前，我们只是没有方法来观察牙釉质的结构，”吉尔伯特说。

But with a technique that I previously invented, called polarisation-dependent imaging contrast (PIC) mapping, you can measure and visualise in colour the orientation of individual nanocrystals and see many millions of them at once.

“但有了我之前发明的一种技术，偏振相关成像对比度(PIC)映射，你可以用颜色来测量和显示单个纳米晶体的方向，同时可以看到数百万个纳米晶体。”

This electron microscopy method, Gilbert says, makes the architecture of complex biominerals "immediately visible to the naked eye", and in doing so, revealed something scientists had never seen before.

吉尔伯特说，这种电子显微镜的方法使复杂的生物矿物结构“立即可以用肉眼看到”，并在此过程中揭示了一些科学家以前从未见过的东西。

When using the PIC mapping technique on human teeth, the researchers observed that the hydroxyapatite nanocrystals were not oriented in the way that researchers had previously assumed.

当在人类牙齿上使用PIC映射技术时，研究人员观察到羟基磷灰石纳米晶体并没有按照之前研究人员设想的那样定向。