The Pomphorhynchuslaevis is a parasitic worm that if often found in certain freshwater amphipods like the Gammaruspulex, which serves as the host for the worms to get proper nutrients. The parasitic worms would often live in the gut wall of the amphipods and will stick on the surface using the tiny hooks that are in their mouths. These tiny hooks allow the worm to remain in place and digest bile that goes through the gut wall, thus being able to be supplied with nutrients. While this species of worms are considered parasitic to amphipods, one of their functions is actually beneficial for humans. So, how do humans benefit from these parasitic worms? Let us find out as we take a look at the amazing origins of the biomimetic skin graft adhesive.
Origins of the Biomimetic Skin Graft Adhesive
In order for us to understand how the mysterious skin graft adhesive works, we must first learn the life cycle of the Pomphorhynchuslaevis and see how they developed the feature that will be used for the biomimetic invention. For the parasitic worm to survive, it would need multiple host species, which means that it wouldn’t just stay on the Gammaruspulex to get nutrients. At the start of the parasite’s life cycle, the female worm would release eggs in water, and then these eggs would later be consumed by an amphipod, particularly the Gammaruspulex. The worms would then hatch from the eggs and will start sticking to the amphipod’s gut wall using their mouths, which features tiny hooks at its surface. These tiny hooks allow the worms to penetrate the gut wall and create tiny perforations where their mouths would remain. In these perforations, the worms will successfully be able to capture bile going through the gut wall and consume it.
Afterward, they will manipulate the behavior of their intermediate host to let it be consumed by its predator, which are usually small fishes like the Leuciscuscephalus or chub. The Gammaruspulex is known to hide away from light, as it is in its instincts to hide from it in order to avoid predators. However, if they are infected by the Pomphorhynchuslaevis, the worms would manipulate the amphipod to seek light, thus being more susceptible to getting preyed upon by chubs. Once the amphipod is consumed, the parasitic worms would then move on to the intestine of the fish to get nutrients. The female worms would then be ready to give birth to eggs, and the cycle of life for the parasites would repeat at the beginning.
The tiny hooks found in the parasitic worm’s mouth is what inspired the research team led by Brigham and Women’s Hospital (BWH) Division of Biomedical Engineering’s head Jeffrey Karp, who began their research on the Pomphorhynchuslaevis in 2012. According to the team, the mouth of the worm, which would penetrate the gut wall of the host using the tiny hooks and make the perforation bigger using a balloon-shaped body part located at the bottom of its mouth, could be a useful feature that can be utilized in adhesives to make their ability to stick to tissues or muscles even better. They were able to replicate the penetrating features of the worm’s mouth and utilize it to create a special microneedle adhesive that penetrates the tissue and swells when exposed to water.
To better explain how the microneedle adhesive works, let us imagine that a surgeon is trying to apply a skin graft to exposed tissue near the skin. The surgeon would use a skin graft that is filled with the microneedle adhesives below it, and once the skin graft is attached to the tissues’ surface, the needles would pierce the surface but only with minimal force. Once the needles are exposed to the moisture or water found in the tissues, they will start to swell up at the bottom, thus further strengthening the adhesive abilities of the skin graft.
The research team at BWH hopes that their newly-developed skin graft adhesive would act as a replacement for medical sutures and staples in the future, as they believe that their invention’s adhesion is better and more durable. It is known in the world of medicine that sutures and staples, while being reliable at allowing skin grafts to stay in place while it sticks to normal skin tissues, are prone to damaging the tissues and causing infections. With the microneedle adhesives, the skin graft will be able to stick to better while also not damaging the tissues where the skin graft will be placed. In addition, since the microneedle adhesives can still stick to surfaces even if they are wet, the research team stated that their invention might also be utilized not only in skin grafts but also surgeries on the internal organs of the human body.