Biological adhesive force as a model: Researchers have developed a tissue adhesive that mimics the substance with which barnacles adhere to rocks or marine animals. The bio-inspired paste can also seal wounds in the “slippery” interior of the body very quickly and thus stop bleeding, tests show. The medical “barnacle glue” has great potential for use in surgery and emergency medicine, say the scientists.
The blood loss must be stopped, otherwise there is a risk of death: This is a major medical problem that has still not been satisfactorily resolved. Sutures are usually used to close wounds – but this relatively time-consuming procedure is often unsuitable, especially in emergency situations. An alternative is plasters loaded with coagulation factors that can stop bleeding. But their possible uses and the adhesive strength in the area of heavily bleeding wounds still leave a lot to be desired.
For several years now, a team of US researchers headed by the Massachusetts Institute of Technology (MIT) in Cambridge has been devoting itself to the development of new possibilities for wound care and hemostasis. The scientists are inspired by concepts from nature. In the current case, barnacles served as a model. These small crustaceans are known for their ability to attach themselves to the surfaces of rocks, ship hulls, and even animals like whales. The amazing thing is that they manage to do this despite the wet, slippery and dirty conditions. “In the marine environment, these creatures do exactly what we have to do to deal with the complicated bleeding problems in the body,” says first author Hyunwoo Yuk from MIT.
Barnacle glue in the sights
The researchers initially devoted themselves to an analysis of the process used by their biological models. It turned out that the barnacle glue has a clever composition: the sticky protein molecules that help the barnacles attach to surfaces are integrated into an oily substance that displaces water and impurities from the target surface so that they can firmly adhere to it . The team tried to imitate this nifty barnacle glue recipe by adapting a previously developed glue. This sticky material consists of a polymer with an organic compound embedded in it that ensures adhesion and sugar compounds that strengthen the material. For the new formulation, the researchers frozen this adhesive and then ground it into microparticles. They then mixed this powder into a medical silicone oil.
Tests showed that the resulting paste has a similar effect to barnacle glue: on a damp surface, the oil repels liquids such as blood and other substances, so that the adhesive microparticles can network with the surface. The researchers initially demonstrated that this also works specifically for wounds through experiments on wounds in rats. Within 15 to 30 seconds of applying the adhesive, it hardens with light pressure, seals wounds and the bleeding stops, according to the result.
Promising test results
In further studies on pigs, the scientists were able to show that the adhesive was able to stop bleeding in the liver faster and more effectively than conventional hemostatic agents. The system also worked when the pigs were given strong blood thinners such as heparin to prevent their blood from clumping spontaneously. Given that many people use such drugs, it has great significance. “Our data show how the paste achieves rapid hemostasis in a non-clotting manner. The resulting tissue seal can even withstand high arterial pressures, ”sums up co-author Christoph Nabzdyk from the Mayo Clinic in Rochester.
The tests also confirmed the compatibility and, above all, the sufficient resistance of the material: The seal remains intact for several weeks, so that the affected tissue can heal. The adhesive is then broken down by the body – but it can also be removed earlier with a solvent if surgeons still have to repair the wound, the researchers report. As they explain, a great advantage of the new adhesive paste is that it can be used on particularly complicated wounds: “The malleable paste can flow into any irregular shape and thus seal it,” says co-author Jingjing Wu from MIT. “This gives users the freedom to adapt them to irregularly shaped, bleeding wounds of all kinds.”
However, development work is still required before the bio-inspired superglue is available: The researchers are now planning to further explore the potential for use and compatibility. “We are now on the way to solving adhesion problems in the difficult environment of human tissue and trying to translate our results into real products that can save lives,” says senior author Xuanhe Zhao from MIT.
Source: Massachusetts Institute of Technology, Mayo Clinic, article: Nature Biomedical Engineering, doi: 10.1038 / s41551-021-00769-y