新發(fā)現(xiàn)的牙釉質(zhì)結(jié)構(gòu)，可能最終解釋了其奇異的強(qiáng)度

新發(fā)現(xiàn)的牙釉質(zhì)結(jié)構(gòu)，可能最終解釋了其奇異的強(qiáng)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.

對(duì)牙釉質(zhì)納米結(jié)構(gòu)的首次研究,有助于解釋為什么人體內(nèi)最堅(jiān)硬的物質(zhì)具有如此難以置信的彈性。

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.

牙釉質(zhì)看起來(lái)像骨頭，但實(shí)際上不是活組織。牙齒的外層——包圍和保護(hù)牙齒內(nèi)部的其他組織——是在我們年輕的時(shí)候形成的，一旦牙齒長(zhǎng)出來(lái)，它就沒(méi)有自我修復(fù)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.

幸運(yùn)的是，產(chǎn)生牙釉質(zhì)的礦化過(guò)程產(chǎn)生了一種難以置信的堅(jiān)韌物質(zhì)，這種物質(zhì)比鋼還硬。新的研究揭示了一種前所未見(jiàn)的機(jī)制，幫助牙釉質(zhì)變得異常堅(jiān)韌。

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.

來(lái)自威斯康星大學(xué)麥迪遜分校的生物物理學(xué)家Pupa Gilbert說(shuō):“我們每天咀嚼幾百次，每次都對(duì)牙釉質(zhì)產(chǎn)生巨大的壓力。”

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

“牙釉質(zhì)是獨(dú)一無(wú)二的，因?yàn)樗掷m(xù)我們的一生。如何防止災(zāi)難性的失敗?”

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.

答案在于研究人員所稱(chēng)的牙釉質(zhì)的“隱藏結(jié)構(gòu)”:構(gòu)成我們牙齒外層的納米晶體的一種極其微小的結(jié)構(gòu)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.

這些極其微小的晶體是由一種叫做羥基磷灰石的鈣磷灰石構(gòu)成的。在其他生物的牙齒中也發(fā)現(xiàn)了同樣的礦物質(zhì)，而且晶體確實(shí)很小，實(shí)際測(cè)量不到人類(lèi)頭發(fā)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.

它們實(shí)在太小了，以前很難看清它們。

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

“在這項(xiàng)研究之前，我們只是沒(méi)有方法來(lái)觀察牙釉質(zhì)的結(jié)構(gòu)，”吉爾伯特說(shuō)。

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.

“但有了我之前發(fā)明的一種技術(shù)，偏振相關(guān)成像對(duì)比度(PIC)映射，你可以用顏色來(lái)測(cè)量和顯示單個(gè)納米晶體的方向，同時(shí)可以看到數(shù)百萬(wàn)個(gè)納米晶體。”

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.

吉爾伯特說(shuō)，這種電子顯微鏡的方法使復(fù)雜的生物礦物結(jié)構(gòu)“立即可以用肉眼看到”，并在此過(guò)程中揭示了一些科學(xué)家以前從未見(jiàn)過(guò)的東西。

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.

當(dāng)在人類(lèi)牙齒上使用PIC映射技術(shù)時(shí)，研究人員觀察到羥基磷灰石納米晶體并沒(méi)有按照之前研究人員設(shè)想的那樣定向。