The researchers surrounding Dr. Jeff Karp, Associate Professor of the Brigham and Women’s Hospital, Harvard Medical School, modeled a new type of medical tape that doesn’t stick to the skin, but bores into the skin with hundreds of tiny needles, after the acanthocephalan worm (Pomphorhynchus laevis) that lives in fish intestines. What sounds uncomfortable is said to actually be completely pain free. Once in the skin, the “spikes“ expand, so that the tape adheres strongly to the skin. According to Karp, the catalyst for this invention were burn patients, whose new, transplanted skin grafts are particularly sensitive and where conventional bandages barely adhere to. The researcher’s goal for the future is also to make it possible to administer drugs such as antibiotics via the spikes of the adhesive bandage. It remains to be seen how patients embrace the new adhesive bandage.
Inspiration doesn’t come from nowhere
The notion of “stealing“ an idea from nature generally has little to do with a sudden burst of inspiration and more with a targeted search. Together with his team, Dr. Oliver Schwarz of the Fraunhofer Institute for Manufacturing Engineering and Automation, IPA, has –among other things- developed a medical drill that can drill holes with an angled diameter. They are needed in hip surgery where an endoprosthesis is being inserted. The team has specifically searched for biological inspirations. Schwarz: “We used the top-down principle to find a solution to our problem. The search is made easier because we are dealing with the same biological material as in nature. There are teeth, trunks or masticatory organs that are already reminiscent of surgical drills or tongs. They can serve as an inspiration, but nature doesn’t offer us a blueprint.“
Ultimately, Schwarz and his team found their solution in an unusual area: with horntails or wood wasps. They are part of the hymenoptera family and are able to bore holes up to six centimeters into the wood – without any rotation! They grate through the wood with their ovipositor. The team transferred this principle to a medical drill. “There is no torque with this kind of drilling; you also need only little axial force, because it works itself into the material by itself. We are not limited to round holes in drilling. When we chip away the bone, we could also create cutouts with triangular or polygonal diameter, depending on the situation. With our device, the surgeon is supposed to receive haptic and acoustic feedback via vibration and the grinding sound in case he or she drills outside of the cancellous bone.“
The surgical drill is planned to weigh 1.5 kilograms; broken down into its individual components, it is meant to be easily sterilized. For now, the device only exists on the drawing board, but a prototype is scheduled to follow soon.
In contrast, the tiny swimming bio-bots by Professor Taher Saif of the University of Illinois follow an entirely different approach. Technically, he models them after sperm and water snakes; however, his swimming microrobots that are someday meant to transport drugs in the human body are propelled by beating heart cells – sort of a bionic bio-tech hybrid. By beating, the heart cells make it possible for a plastic tail that is just 7 micrometers wide and one and a half millimeters long to be bent frequently, thus creating a wave motion that propels the tiny bot forward. However, systematic navigation requires several plastic tails. It will be interesting to see whether and when this new technology makes its way into medicine.
One thing is for certain however: nature will still give us many solutions, in part by accident and in part because we are actively searching for them. It will therefore be interesting to see what kind of help nature will give us in other medical technology questions.