Last year, scientists at Tufts University, in Boston, USA developed a Spider-Man-inspired web shooter capable of transforming liquid silk into sticky fibres. This remarkable innovation recreates the web slinging technology once confined to the realm of comic books.
The research team, led by Marco Lo Presti at Tufts University’s Silklab, created a hydrogel silk solution derived from Bombyx mori silkworm cocoons. When extruded through a specialized needle device, this solution transforms into sticky fibres upon contact with air. While cleaning glassware with acetone, Lo Presti’s eureka moment came unexpectedly: “I noticed web-like material forming at the bottom,” an observation that later informed the creation of the hydrogel silk solution.
By mimicking these natural processes, the Tufts team has created a material that bridges biology and engineering, highlighting the possibilities of biomimetic design. Fiorenzo Omenetto, the director of Silklab, remarked, “We can be inspired by nature. We can be inspired by comics and science fiction. In this case, we wanted to reverse engineer our silk material to behave the way nature originally designed it, and comic book writers imagined it.”
Nature has continuously inspired advancements in silk-based technologies, with spider silk serving as a prime example of biomimetic innovation. Spiders are well-known for their web-spinning abilities, as “they usually spin their silk out of their gland, physically contact a surface, and draw out lines to construct their web,” as articulated by Lo Presti. However, unlike Spider-man, “spiders cannot shoot their web,” he adds.
To mimic this superhero’s unique web shooting ability, the researchers created an innovative technology combining silk fibroin and dopamine. Dopamine, a hormone in the brain responsible for pleasure and motivation, is also used to enhance the strength of adhesives. Silk fibroin usually takes hours to solidify when exposed to solvents. By adding dopamine and chitosan (derivative of insect exoskeleton), the process is accelerated, allowing the silk to solidify instantly upon ejection. This chemical synergy increases the tensile strength (the maximum amount of stress the silk can withstand before snapping) of the fibres by an astounding 200 times and enhances their stickiness 18-fold.
This enables the web to lift objects more than 80 times its own weight. It has successfully retrieved items such as cocoons, steel bolts, and even a scalpel buried in sand. “We are demonstrating a way to shoot a fibre from a device, then adhere to and pick up an object from a distance,” Lo Presti emphasised, highlighting the potential for real-world applications. In fact, in an experiment, the silk was able to lift a 5g wood block from a distance of 12 centimetres.
The versatility of the technology is further demonstrated by its adjustable fibre diameter, which can range from the width of a human hair to half a millimetre, depending on the needle bore used. While natural spider silk is about 1,000 times stronger than these synthetic fibres, this comparison highlights the gap researchers are striving to close. Ongoing engineering advancements could lead to more robust and versatile materials in the future.
As research continues, this Spider-Man-inspired web-slinging technology opens up possibilities for various applications, including remote object manipulation, adhesive applications in industries, and potential advancements in materials science. This shows how nature-inspired designs can address scientific challenges.