The Toughest Fiber in the World Spider Silk with Graphene

The silks showed enhanced mechanical properties compared to reference silks collected from the same spiders, with significant increases in the strength, toughness and elasticity of the biocomposite silk threads. The strongest silk threads had a fracture strength of up to 5.4 GPa, over 3 times as strong as the unmodified silks, as well as a tenfold increase of toughness modulus up to 2.1 GPa.

This study opens up new potentials for tailoring the properties of biological materials to enhance their properties for use in novel applications. For example, these artificially modified silks could find use in high-performance or biodegradable textiles such as parachutes or medical dressings.

“Humans have used silkworm silks widely for thousands of years, but recently research has focussed on spider silk, as it has promising mechanical properties. It is among the best spun polymer fibres in terms of tensile strength, ultimate strain, and especially toughness, even when compared to synthetic fibres such as Kevlar,” said Nicola Pugno, of the University of Trento.

“We already know that there are biominerals present in the protein matrices and hard tissues of insects, which gives them high strength and hardness in their jaws, mandibles and teeth, for example. So our study looked at whether spider silk’s properties could be ‘enhanced’ by artificially incorporating various different nanomaterials into the silk’s biological protein structures,” said Pugno.

“This is the highest fibre toughness reported to date, and a strength comparable to that of the strongest carbon fibres or limpet teeth,” said Pugno. “These are still early days, but our results are a proof of concept that paves the way to exploiting the naturally efficient spider spinning process to produce reinforced bionic silk fibres, thus further improving one of the most promising strong materials.”

Sophia Lloyd