Page 36 - Biomimetics: Technology Imitates Nature

Biomimetics: Technology Imitates Nature

100 nm • It can stretch up to four
diameter
2μm 50 nm times its own length.
• It is also so light that
enough thread to stretch clear
20 Å
1 cm around the planet would
weigh only 320 grams.
50 Å
These individual charac-
Matrix teristics may be found in var-
Contains polyalanine crystals
20 Å ious other materials, but it is a
NPL crystal
Contains polyalanine crystals most exceptional situation for
them all to come together at
once. It’s not easy to find a
material that’s both strong
Gly Gly Gly Ala Gly Other ß sheet and elastic. Strong steel cable,
Ala Gly
Tyr Pro Pro
Ala X1 for instance, is not as elastic
Gly Gly Gly Ala Gly
Pro Gly Gln Ala Gly 10 Å as rubber and can deform
Gly Tyr Gln Ala X2
Matrix NPL crystal over time. And while rubber
Spider silk, possessing an exceedingly complex cables don’t easily deform,
structure, is but one example of God’s incom-
they aren’t strong enough to
parable art and infinite wisdom.
bear heavy loads.
How can the thread
spun by such a tiny creature have properties vastly superior to rubber and
steel, product of centuries of accumulated human knowledge?
Spider silk’s superiority is hidden in its chemical structure. Its raw
material is a protein called keratin, which consists of helical chains of
amino acids cross-linked to one another. Keratin is the building block for
such widely different natural substances as hair, nails, feathers and skin.
In all the substances it comprises, its protective property is especially im-
portant. Furthermore, that keratin consists of amino acids bound by loose
hydrogen links makes it very elastic, as described in the American maga-

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