Scientists at Tufts University are inspired by the abilities of the comic book superhero Spider-Man by developing a fluid that transforms into strong, sticky fibers that can lift objects several times their weight. Great progress has been made.
For years, researchers have sought inspiration from the silk secreted by various insects, including moths and spiders, to create durable fibers that act as tethers.
However, replicating the stiffness, elasticity, and adhesive properties of spider silk has so far proven difficult.
According to a study published in Advanced functional materialsResearchers have discovered that when a silkworm protein known as fibroin is fortified with certain additives, it can be shot through a thin needle to form tough, sticky fibers.
“I was working on a project using silk fibroin to make a very strong adhesive, and as I was cleaning glassware with acetone, I noticed that a cobweb-like substance had formed on the bottom of the glass. “I realized that,” said Marco Lo Presti, co-author of Silk Fibroin. the study.
When researchers initially tried to replicate spider silk, they discovered that the fibroin solution turned into a semi-solid gel when exposed to chemicals such as ethanol or acetone for more than a few hours.
However, the introduction of dopamine accelerated the coagulation process and produced high-tension, sticky fibers almost instantly.
The scientists explained that the dopamine mixture accelerates the liquid-to-solid transition by extracting water from silk proteins.
Remarkably, they observed that a thin stream of silk solution wrapped in a layer of acetone solidified into sticky fibers when injected through a specially designed needle. Once the acetone evaporated, the fibers stuck to any object they touched.
Adding chitosan, a protein found in insect exoskeletons, increased the tensile strength of the fibers by up to 200 times, and chemicals such as borate buffers increased adhesion by about 18 times.
The fiber diameter can be adjusted from the thickness of a human hair to approximately 0.5 mm depending on the needle hole.
The newly developed fiber has demonstrated the ability to lift objects weighing more than 80 times its own weight.
During the experiment, they were able to pick up various objects from a distance of about 12 centimeters, including a steel bolt, a floating test tube, a scalpel partially buried in sand, and a block of wood.
Spider silk is still about 1,000 times stronger, but researchers believe new fibers can be purified for a variety of uses.
“This process can be fine-tuned to achieve controlled production of adhesive hydrogel fibers that form instantaneously,” added Dr. Lo Presti. “This is really superhero-inspired material.”
