➤ By Elliott Kennerson
➤ Source: npr health news
➤ Compiler: Wensi Zhang, a student at the American Fortress Military Academy
To replace needles and threads and screws, doctors are tinkering with a new generation of medical adhesives, glues, and tapes.
Where did they get their inspiration? Aquatic oysters, marine worms and stone moths, an insect that inhabits the crevices of streams across the United States and is often used as bait for fishing.
Nowadays, the medical adhesives used by doctors are very well used outside the body, attaching waterproof bandages to dry skin and lasting for a period of time, and certain brands of liquid adhesive substances, such as "Super Glue" and "Crazy Glue", which contain so-called cyanoacrylate compounds, can enhance the corrosion resistance in water.
The real challenge for medical engineers, however, is to produce adhesives that ensure that they remain firmly attached to objects in the water.
"Typically, the adhesives we make are stable underwater." Nicholas Ashton said he was a PhD student in bioengineering at the University of Utah, "but we can't keep the form of the binder." ”
60% of the human body is made up of water, and the inside of our body is like a flowing fish tank, and due to the hostility of chemical binders, doctors have traditionally used mechanical means to repair bones and suture internal tissues.
"When you walk into the human body for the second time, he will completely change the rules of the game." Ashton said.
In the recent world of stone moths, this insect that inhabits streams secretes a waterproof slime to build a nest, and in its larval stage, this industrious architect will use pebbles and their double-sided glue-like slime to build a small tubular nest. It's all happening underwater. This tape-like mucus is a silky substance secreted by a pair of glands in their jaws.
Thanks to this silky substance, the nest is not only waterproof but also strong enough to withstand the body weight of the larvae and multiple shocks.
"It's a wonderful kind of tape." Russell Stewart said he is an engineer majoring in materials science at the University of Utah and is currently studying the viscous filaments secreted by stone moths.
This nest-building process begins as soon as the stone moth hatches.
"And when they build nests, they are selective." Gusse Mendes said he is an environmental entomologist at the University of California, Berkeley.
"After carefully selecting the first pebble (also known as the cornerstone) as its nest, the stone moth carefully glued the individual stones together to make the nest take shape step by step."
California is home to stone moths, with about four hundred species, and more than fifteen thousand species of stone moths distributed around the world, all using similar filamentous mucus.
Any mucus, including this one of stone moths, has two basic components, and the scientists explain that one is a smooth banded layer, or dorsal layer. The other layer is a slimy glue layer, and from the material point of view, the mucus of the stone moth is prominent in both parts.
Although its mechanism is still unknown, the glue layer is partly composed of complex polymer bonding, which is physically and chemically connected. This adhesive will replace water as a contact surface for the stone and allow the two substances to combine.
Interestingly, unlike most glues, which are used on dry and smooth surfaces, stone moth glue adheres better on silt-filled surfaces that have been corroded by running water and bacteria.
Scientists say the moth's adhesion system, unlike other deeply studied binder producers such as sea cucumbers and shellfish, will give researchers an unusual direction of underwater adhesive research.
The sticky filament of the banded part of the stone moth is elastic, like a rubber band. The adhesive thread can be lengthened by twice its original length and returned to its original shape. But unlike rubber bands, the stone moth's sticky filaments are slow to return to their original shape. This filamentous fiber can absorb the enormous force that arises when another stone vibrates, Stewart explains.
Given the challenging living environment of the larvae, this adhesive "mortar" enhances the robustness of the cobblestone nest. Stewart uses an earthquake example metaphor, "If you consider building a house made of bricks and stones, it will be fragile." "You don't want to live in a stone house in California where it would collapse and collapse if an earthquake came, but if the mortar that bonded the house was elastic, it wouldn't collapse." ”
In comparison, the cobweb is tougher, but it is not durable. If an insect breaks a spider's web, it has to re-weave a web. (Spider silk also loses its elasticity underwater.)
Research to mimic stone moths to make viscous filaments is still in its infancy, and with the help of chemical models, Stewart and his colleagues were able to reverse engineer the primary version of glue adapted to water that solidifies and remains tough. One day, a similar synthetic may be used inside the human body to repair soft tissues, such as organs and tendons, or even hard tissues such as teeth or bones.
Eventually, the larvae of the stone moth seal the top of its nest with a pebble called the "hat stone" and reinforce its interior with additional adhesive,
Like butterflies and moths, relatives who parted ways with their land surface 250 million years ago, the stone moth larvae later underwent a metamorphosis to become winged adults.
This process often occupies people's imagination.
This article and video is provided by deep look, KQED and PBS Digital Studios in a series of wild life films, with a report contributed by Lisa Potter.