Animal superglue decrypted
Scientists at the University of Kassel have deciphered the mode of action of a recyclable animal superglue. The secretion of the so-called stump-foot could be the template for the development of new biomaterials for medicine and sustainable industry.
In a study that has now been published in the renowned journal Nature Communications, an international team of researchers led by Prof. Dr. Georg Mayer, head of the zoology department, and his colleague Alexander Bär describe the functioning and structure of a glandular secretion of an Australian colobus. The over 300 million year old stubby feet (onychophores) catch their prey with the help of a quick and extremely sticky slime, which the animals shoot from paired, specialized nozzles on the head.
According to the investigations, the mucus of the stump-footed species Euperipatoides rowelli consists of tiny, uniformly large, spherical fat-protein structures. When the slime is touched, these nano-spheres deform due to shear forces and stiffen into microfibers made of a tensile protein core and a sticky surface. As a result, the secretion adheres strongly and in a matter of seconds to almost all surfaces. However, if the bio-adhesive is exposed to water for a long time, the polymers will dissolve again. Since the original nano-spheres recede, the secretion could be reused.
"To our surprise, we found a kind of reusable animal glue," says Mayer. “Our study provides important information on how recyclable polymers are formed in nature in an unprecedented way. If we understand even better how these physicochemical processes work, this opens up interesting perspectives, especially in the area of operative medicine, but also for sustainable industrial polymer production. ”The researchers' next goal is now to synthetically replicate the bio-superglue.
In their experiments, the mucus of the onychophores was first collected. This was then examined for its structure and composition during microfiber formation. In addition to their experiments, the researchers also used high-speed images.
Scientists from Heinrich Heine University Düsseldorf, the Max Planck Institute for Colloid and Interfacial Research in Potsdam and McGill University in Montreal / Canada also participated in the study, which was mainly funded by the German Research Foundation.
The onychophores, translated as claw carriers, are invertebrates and resemble worm-shaped caterpillars with short legs and paired antennas. From two openings on the so-called mucus papillae next to the mouth, the animals, some of them up to 22 cm in size, expel a strongly adhesive weir secretion, which is used for defense and for catching prey. They live mainly in the southern hemisphere and around the equator. Around 200 species are known and registered so far, but there are probably several thousand. The stubby feet live mainly in dead wood or in the chaff layer of the forest floor. (sb, pm)