“For this study, we created a solution of water and nanomaterials, carbon nanotubes, and graphene,” Pugno told Digital Trends. “We then sprayed this solution into a box of spiders, where it would likely be ingested. When the spiders spin their webs, we saw that the silk contained the nanomaterials. When we tested this silk with a nano-tensile testing machine, we found that it was stronger and tougher than regular silk.”
The silk produced as part of the study has a fracture strength up to 5.4 gigapascals, and a toughness modulus up to 1,570 joules per gram. By comparison, regular spider silk has a failure strength of around 1.5 gigapascals, and a toughness modulus of just 150 joules per gram.
Spider silk is of interest to engineers and material scientists because of its unique properties — including strength that’s equivalent to steel, toughness that’s superior to Kevlar, and an impressive amount of flexibility. Other varied spider-silk-based projects we’ve covered recently include extreme shock-absorbing spider silk, and the use of it as a biomedical material in repairing extensive nerve injuries. In the case of Pugno’s research, it’s too early to talk specific use cases, although strengthened spider silk would likely be greatly appreciated by researchers working on a broad range of applications.
Pugno said that he was not surprised by the findings of the experiment, since previous studies have shown that diet can play a role in the properties of silk. This has been most widely studied among silkworms, most notably in a 2013 study that found silkworms fed on mulberry leaves that had been sprayed with fabric dyes went on to produce colored silk.
A paper describing the research was recently published in the academic journal 2D Materials.
