Slime mucus has extremely useful properties
Can the slime of a common snail be used as a kind of medical glue in the future? Researchers have now found that a new bio-adhesive from the slime of a slug is incredibly strong, adapts to body movements and also adheres to wet or damp surfaces. Physicians have even managed to seal a hole in a pig's heart with the help of the adhesive.
The scientists at the internationally recognized Harvard University have now succeeded in developing a special bio-adhesive based on the slime of a snail. This adhesive could be used in medicine in the future, for example to close wounds, the experts report in a press release on the results of their study.
Normal plasters adhere poorly to wet tissue
If you've ever tried sticking a patch on damp skin, for example, you should know how frustrating this process can be. Wet skin is not the only challenge for medical adhesives. The treatment of various internal injuries can also be complicated because the human body is full of blood and other fluids, the researchers explain.
New adhesive has two special properties
Many of the adhesive products used today are toxic to the cells, and they become inflexible as soon as they dry. The main feature of our material is the combination of a very strong adhesive force and the ability to transfer and dissipate stress, says author Dr. Dave Mooney. So far it has not been possible to combine these properties in a single adhesive.
Arion subfuscus exudes special mucus
When the researchers thought about how to improve medical adhesives, they found the solution in a snail. The brown slug (Arion subfuscus) is a type of slug that is widespread in Europe and parts of the United States. In the event of danger, the snail exudes a special mucus that should stick to it on the spot. This makes it difficult for other animals to remove the snail from the surface, the experts explain. The mucus is interspersed with positively charged proteins. The researchers were inspired by the mucus to develop a special hydrogel. This consists of a so-called alginate-polyacrylamide matrix, which has an adhesive layer with positively charged polymers.
Why is the new adhesive so strong?
These polymers bind to biological tissue through various mechanisms: electrostatic attraction on negatively charged cell surfaces and covalent bonds between neighboring atoms and physical penetration, the scientists explain. These mechanisms make the adhesive extremely strong. Most material designs to date have focused only on the interface between the fabric and the adhesive. The new adhesive is able to dissipate energy through its matrix layer. This enables him to deform much more, the researchers further explain.
The adhesive can absorb a large amount of energy
The team's design for the matrix layer includes calcium ions that are bound to the alginate hydrogel via ionic bonds. When the adhesive is subjected to stress, these ion bonds break first. This allows the matrix to absorb a large amount of energy before its structure is compromised, the authors say. Experimental trials required more than three times the energy to interfere with the adhesion of the hard adhesive compared to other medical adhesives. When the adhesive finally broke, it affected the hydrogel, but not the bond between the adhesive and the tissue. The experts explain an unprecedented level of simultaneous high adhesive strength and matrix toughness.
Trials of new glue have been very successful
The researchers tested their adhesives on a variety of dry and moist pig tissues, including skin, cartilage, heart, artery, and liver. They found that the bond was significantly stronger with all tissues than with other medical adhesives. Even two weeks after an implantation in rats or to seal a hole in a pig's heart, the adhesive maintained its stability and binding, say the doctors. In addition, the adhesive did not cause tissue damage or adhesions to the surrounding tissue when used in mouse bleeding.
Adhesives have numerous uses in the medical field
Such a high-performance material has numerous uses in the medical field. Either as a patch or as an injectable solution for deeper injuries. It can also be used to attach medical devices to their target structures, such as an actuator to support cardiac function.
The author Dr. Adam Celiz continues: “We can make these adhesives from biodegradable materials so that they decompose as soon as they have served their purpose. We could even combine this technology with soft robotics to form sticky robots, or with drugs to create a new vehicle for drug delivery. ”(As)