Spider silk beats steel, but we're stumped

This super-strong spider fiber is tougher than steel, yet we can't replicate it

By Smartasaurus· 1 min read Curious

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The short version

This super-strong spider fiber is tougher than steel, yet we can't replicate it
We have known the rough chemistry for decades.
We invented Kevlar in 1965.

If you scaled a spider's dragline silk up to the thickness of a pencil, it could stop a Boeing 747 in flight.

That is not a metaphor. It is the math. Dragline silk has a tensile strength comparable to high-grade steel and a toughness — the energy it can absorb before breaking — that exceeds Kevlar. It is biodegradable. It is produced at room temperature, in water, from a paste of protein. Our best industrial fibres require furnaces, solvents, and a lot of regret.

A spider makes it inside a gland about the size of a sesame seed. Liquid silk protein enters one end as a sort of structured goo. As it travels through a narrowing duct, water is pulled out, salts are swapped, the pH drops, and the molecules align under shear stress. By the time it exits the spinneret, the protein has assembled itself into one of the strongest materials biology has ever evolved.

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