Researchers at Tufts University have developed a new technology making Spider-Man’s web-slinging a reality.
The device can shoot a fluid, which instantly turns into a solid string. This string can stick to objects and even lift them. The idea is inspired by the silk used by spiders and moths to create webs.
Silk-based technology
The invention, developed in the Silklab at Tufts University, uses silk from moth cocoons. Researchers break down the cocoons into a protein called fibroin. This liquid silk is pushed through thin needles, and when exposed to air, it turns into a solid fiber.
The process mimics how insects like spiders, ants, and moths produce silk for webs, cocoons, and egg protection.
The team at Silklab has also used silk to create useful materials, such as strong glues, sensors that stick to surfaces, and coatings that help keep fruits and vegetables fresh. They are even exploring ways to improve solar panel efficiency with silk.
Accidental discovery of web-like material
One of the breakthroughs in this research was actually coincidental. Marco Lo Presti, a research assistant professor at Tufts, discovered it while cleaning glassware with acetone. He noticed a web-like material forming at the bottom of a glass.
Normally, silk fibroin turns into a gel slowly when exposed to solvents such as ethanol or acetone. When dopamine, a substance used in making adhesives, was added, the process became much faster. This quick solidification allowed the silk solution to immediately create strong and sticky fibers.
Improving the fibers
The next step was to spin the fibers in the air. By adding dopamine to the silk solution, researchers sped up the shift from liquid to solid by drawing water out of the silk. They then pushed the solution through a special needle surrounded by acetone. As the acetone evaporated, it left behind a solid fiber that stuck to any surface it touched.
To further improve the fibers, the team added chitosan, a material from insect shells. This made the fibers up to 200 times stronger. They also used a borate buffer, which made the fibers 18 times stickier. The size of these fibers could be adjusted from the width of a human hair to about half a millimeter, depending on the needle size.
The device can shoot fibers that lift objects more than 80 times their own weight. Researchers demonstrated this by lifting a cocoon, steel bolt, floating lab tube, a scalpel buried in sand and a wood block from about 12 centimeters away.
Lo Presti explained that, while spiders can’t shoot webs, they spin silk and pull it to create their structures. In contrast, this new technology shoots fibers and sticks them to objects from a distance.