A Stinger of a Bee and an Elephant’s Trunk serve as Inspiration -- COMPAMED Trade Fair

A Stinger of a Bee and an Elephant’s Trunk serve as Inspiration

How can you design a product or make it better? What kind of questions do I need to ask to find the solution to a problem and what can I use as a role model? These questions don’t just keep modern science busy, but have already challenged many inventors centuries ago. One method that proved successful was using living nature as a model.

Leonardo da Vinci or the Wright brothers already studied birds to build flying machines that were intended to carry humans through the air. Today we speak of Bionics when we talk about such technical implementations, borrowed from nature. Unlike the early beginnings, scientists today – thanks to modern technology – take a very close look. After all, the uniqueness of many designs by Mother Nature is in their detail.

It all depends on the question

At first you need to be clear about the question though. Professor Werner Baumgartner, Chair of the Department of Cellular Neurobionics at the Rhenish Westphalian Technical University Aachen (RWTH) sums it up like this: ”There are two approaches, the top-down and the bottom-up approach. Top-down approach means an engineer has a precise problem. He wants to achieve an increase in efficiency for instance or create a new form of circulation on a surface. That’s why he asks the biologist: Is there something along these lines in nature? Has nature already faced this type of problem and solved it during the course of evolution? In the bottom-up process on the other hand, biological fundamental research is being conducted. One asks for example why an animal or a plant does one thing or another. At first that’s just done to gain the knowledge. The scientist of course keeps the question in mind and whether it’s possible to develop an interesting product from this. “

Particularly interesting are those things, that don’t immediately attract attention through an obvious connection. That’s because Bionics does not copy nature: “Bionics certainly does not mean to copy something exactly as it is, but rather to develop something for a corresponding application”, says Baumgartner. Even though some connections appear to be obvious, like for instance when one thinks about the injection needle of a syringe and the stinger of a bee. But the expert points out: “The bee for instance is not made to where it could inject a drug into a human being in the most sterile and pain-free way possible. It does something similar instead and has accomplished an optimization for its own use. In Bionics you adopt the principle. “



An elephant trunk in rehabilitation

Using this principle, researchers of the Fraunhofer Institute for Manufacturing Engineering and Automation IPA won the German Future Prize 2010 on December 1 for developing a bionic arm that was built after the model of an elephant’s trunk and is also labeled as a Bionic Handling Assistant. The Bionic arm can be used in industry as well as in rehabilitation or household applications. The individual components of the Bionic arm were generatively manufactured and – similar to an accordion- are moved by pressurized air. At the end of the trunk is a “gripper“ with three fingers.

And even though it can gently grip things like an elephant’s trunk can, it yet is based on an entirely different principle: a trout’s tail fin. Just like the fin, the fingers are not buckling down if they touch an object, but instead clasp it. A successful combination of different technologies therefore, that’s typical in Bionics. Professor Antonia Kesel, Head of the International degree course Bionics (ISB) at the University of Bremen: “Theoretically, you can envision all combinations. There are about 20 million species, not counting bacteria. And each of these species comes with characteristics that might be potentially interesting to Bionics. If you have a multicomponent problem for instance for which you seek possible solutions, you can fall back on the most varied of species – this can make for a colorful bunch of model organisms. “



Wanted: The perfect material

Important for the implementation of a Bionic vision besides the initial idea is of course also the material you work with. Today hip endoprosthesis for instance in many cases are made of surgical steel or titanium. Both materials are convincing due to their special physical endurance. Yet there is one problem: the body identifies them as foreign objects. That’s why they don’t grow in properly in some cases and are then not able to serve their purpose. Scientists therefore want to find a way to make endoprostheses biocompatible. Baumgartner explains: “If it’s at all possible, the body should not identify an endoprosthesis as foreign, because cells should grow on the surface. That’s why we also look at what nature offers in that regard. We ask: How does nature cover surfaces for instance, so tissue can grow there and something can adhere, meaning tissue adheres to the surface.“ If for example there was a way to coat the surface of a prosthesis to where the surrounding tissue “likes“ it, the life of implants could certainly still be further increased. Baumgartner also sees many research opportunities in this area: “Particularly at the interfaces between human being and technical surface there is still lots to be done and a lot of research takes place.“

Unfortunately, beyond that it takes some time before research results find their way into company production – if it actually happens, because many a great idea can not be as well implemented than originally hoped. Exciting research topics in the field of endoprosthetics currently pertain to biomaterials. They are more similar to our body tissues than titanium for instance and should therefore harmonize better with our body’s own tissue.

Mother-of-pearl coatings for knee joint- or hip prostheses are also being researched right now. Since mother-of-pearl is similar in construction to a brick wall, the material would also ensure a longer life of the implant. A long crack, like the ones that occur in conventional prosthesis, is rarely possible anymore with mother-of-pearl due to its layered structure. Since 2008 scientists at the Hannover Medical School are working on the implementation.

Simone Ernst

(Translated by Elena O'Meara)