A group of researchers from Silklab at the Tufts University recently created an extraordinary material: a viscous, silk-based substance that, when expelled from a needle, instantly solidifies into a strong fiber capable of lifting objects up to 80 times its weight. This discovery, inspired by the superhero Spider-Manis getting closer and closer to the possibility of having technology similar to the famous spider web launched by the comic book character.
How the silk-based “Spider-Man” fiber was born
The idea of developing this fiber was born almost by chance. Marco Lo Prestilead author of the study and associate professor at Tufts University, was working on creating powerful adhesives using silk fibroin, a protein produced by silkworms. During one experiment, Lo Presti noticed that the substance formed a web-like structure at the bottom of a glass container cleaned with acetone. This discovery prompted the team to experiment further: they mixed fibroin with acetone, resulting in a semi-solid hydrogel. By adding dopamine to the mixture, the liquid compound solidifies almost immediately, turning into a sticky and very resistant fiber.
Not satisfied, the researchers then integrated another substance, chitosan, a natural biopolymer derived from crustacean shells. This further improved fiber adhesion and strength, increasing by 18% and 200% respectively. The team then built a device capable of shooting the liquid towards objects, demonstrating the ability to lift steel bolts about 12cm away and weighing 80 times that of the fiber itself.
Why not use spider silk?
Although spider silk is considered one of the strongest natural substances, with properties superior even to steel in proportion to weight, the researchers chose to work with silk fibroin produced by silkworms. Spider silk is much more complex to reproduce artificially and the characteristics can vary greatly between species, making practical and controlled use difficult.
In contrast, silkworm silk is easy to produce and modify in the lab, allowing researchers to tailor its strength and adhesiveness as needed, making it useful in many applications, from soft robots to drug delivery to biodegradable sensors.
