Scientists have enhanced silkworm silk to make it one of the strongest materials ever – stronger that spider’s silk. But how? 

New Scientist magazine reports in October 2022 on recent research in which standard silkworm silk has been made stronger than spider’s silk, one of the toughest materials on Earth. 

Scientists bathed silkworm silk with metals and re-spun it. They dissolved silkworm silk and re-made it in a solution of sugar, zinc, and iron metal ions. This is called metal-enriched silk.

Scientists have been trying to improve on spider silk for a long time. They want a super strong substance because collecting spider silk is difficult. They used silkworm silk because it is more easily produced and collected than the silk spun by spiders. But silkworm silk is not as strong as spider silk. 

At Tianjin University in China, scientist Lin Zhi and his colleagues developed a method to strengthen silkworm silk by first dissolving it in sodium carbonate or papain (an enzyme from papaya fruit) and then re-spinning it in a bath of sugar, ethanol, zinc and iron metal ions.

Lin Zhi said that the technique opens up ways to produce profitable high-performance artificial silks that are stronger than natural silks. The properties of stiffness and strength are better than natural spider silk. 

However, there is one spider that has silk even stronger than the metal-enriched artificial silk. That is the Golden Silk Orb-Weaver Spider (Nephila calvipes). If this silk is properly collected, it is stronger than metal-enriched silk, with a tensile strength of up to 2.9 gigapascals (GPa). Most spiders have silk with a strength of 0.9 to 1.4 GPa, whereas metal-enriched silk has a strength of 2.0 GPa. 

Journal reference: Matter, DOI: 10.1016/j.matt.2022.08.028

Photographer: Martina Nicolls

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