Epidermis-Honeycomb-Water Cube 表皮-蜂巢-水立方
130 years ago, Lord Kelvin asked how space might be partitioned into cells of fixed equal volume with minimum surface area [1]? Although his work was dismissed as “a pure waste of time” by his colleagues, he worked out through intensive calculation and proposed a fourteen-face shape (tetradecahedron) that when positioned together formed a beautiful honeycomb like structure.
The outermost layer of our skin is called epidermis which is made up of between fifty and one hundred layers of keratinocytes. Scientists [2,3] discovered that our keratinocytes adopt this unique fourteen-face shape structures. So even though our skin cells are always on the move before flaking off, the surface contacts between cells and so tight and ordered that water still can not get through. It turns out that our skin is the ideal waterproof foam.
Keratinocytes creata a fine but formidable outer defence, protecting the trillions of cells inside our body. Coated in antimicrobial molecules and acids, our outer defences of the epidermis are chemically and physically designed to keep out unwanted visitors, from insects, bacterial, virus to irritants, and to keep in moisture.
Do you not know?
Have you not heard?
The Lord is the everlasting God,
the Creator of the ends of the earth.
He will not grow tired or weary,
and his understanding no one can fathom.
— Isaiah 40:28 NIV
130年前，开尔文男爵威廉·汤姆森问了一个几何问题，如何将空间分割为具有界面表面积最小并且有固定相等体积的单元[1]？尽管他的工作被同行们视为“浪费时间”，但他通过大量的计算得出了结论，并提出了一个十四面体形状，当放置在一起时会形成漂亮的蜂窝状结构。
我们皮肤的最外层称为表皮epidermis，由五十到一百层角质形成细胞keratinocyte组成。科学家发现[2,3]我们的角质形成细胞采用了这种独特的十四面形状结构。因此，即使我们的皮肤细胞在剥落前始终处于向外层运动状态，细胞之间的表面接触仍是如此紧密和有序，以至于水都无法通过。事实证明，我们的皮肤是理想的防水泡沫。
角质细胞keratinocyte创建了细微但强大的外部防御层，保护我们体内的数万亿个细胞。表皮的外部防御层还有抗菌分子和酸，在化学和物理上均经过精心设计，以阻止有害的访客进入，从昆虫，细菌，病毒到刺激物，并保持体内水分。
你岂不曾知道吗？ 你岂不曾听见吗？
永在的上帝耶和华，创造地极的主， 并不疲乏，也不困倦；
他的智慧无法测度。
— 以赛亚书 40:28
Reference:
- Thomson, W. (1887) On the division of space with minimal partitional area. Philosophical Magazine. 24: 503
- Mariko Yokouchi, Toru Atsugi, Mark van Logtestijn etc. Epidermal cell turnover across tight junctions based on Kelvin’s tetrakaidecahedron cell shape. eLife 2016;5:e19593 DOI: 10.7554/eLife.19593
- Mariko Yokouchi Akiharu Kubo. Maintenance of tight junction barrier integrity in cell turnover and skin diseases. Experimental Dermatology, August 2018. Volume 27, Issue 8, Pages 876-883
