Replace cartilage with bio-ink


EUR 10 million grant from the Werner Siemens Foundation for the tissue replacement of the future from Aachen, Germany

Growth and replacement of damaged cartilage tissue with the help of a ground-breaking 4D printing technology: This is what a team of scientists from the DWI – Leibniz Institute for Interactive Materials in Aachen is striving for. It is receiving a five-year grant of around 10 million euros from the Werner Siemens Foundation to develop a so-called bio-ink with special properties in the "TriggerINK" project.

The human body is made up of an abundance of differently structured and sometimes very complex tissues. If they are damaged, medicine faces major challenges in restoring their function. Although there are procedures to repair cartilage in the knee, such interventions do not lead to a long term solution to replace the damaged tissue and regain its function. In addition, several interventions are often necessary as the treatments do not lead to stable, healthy and functional cartilage.

4D printing - potential for the cartilage replacement of tomorrow

An interdisciplinary team from the DWI Leibniz Institute for Interactive Materials and the RWTH Aachen University aims to develop an alternative technology for tissue replacement in the TriggerINK project. It is led by Laura De Laporte, Professor of Advanced Materials and Biomedicine. TriggerINK uses the innovative principle of 4D printing, for which a special bio-ink is being designed. 4D printing is a further development of 3D printing technology: in standard 3D printing, layer by layer of a material is often applied on top of each other, creating a three-dimensional structure - like a cube. "The additional factor that also gives 4D printing its name is 'time': we incorporate special components into the ink that react to external stimuli at very specific times. For example, when staying with the cube, movement of the printed material is possible with light and bioactive components can be released on demand with ultrasound," explains the chemical engineer.

The team now wants to use TriggerINK to develop a new method for replacing damaged tissue: By means of direct printing of 4D structures into the affected wound. To test the technology, the researchers have selected cartilage in the knee joint. "We face a variety of challenges in regrowing healthy tissue in damaged areas. For example, the printed material must have a very specific structure comparable to its natural counterpart. It therefore contains pores and aligned structures, which are very important to direct infiltrating cells to form tissue that is able to fulfil its function and - in the case of the knee joint - withstand pressure or frictional stress," explains chemical engineer Matthias Wessling. His research focuses, among other things, on the process engineering requirements for printing of ordered structures.

Bundled knowledge as the key to success

TriggerINK is a prime example of how innovative science projects can be organized: They combine the knowledge of a wide range of disciplines. With Laura De Laporte and her expertise in developing biomedical materials, a total of four leading experts in their respective fields combine their skills: Professor colleagues Stefan Hecht (3D printing by light), Andreas Herrmann (drug release by ultrasound) and Matthias Wessling (chemical engineering) complete the team. "It is a real specialty and privilege that we have such diverse knowledge under one roof at the institute. Because of this home advantage and the special organizational form with a start-up-like structure of the project, we are confident that we will be able to drive this development forward in big steps," explains chemist Stefan Hecht. But it doesn't stop with this group of people: "We are striving to develop a medical product - which means that the perspective of users from the clinic is also indispensable for us. For this reason, we are also accompanied and advised by high-ranking colleagues from the fields of medicine and molecular cell biology," he adds.

One ink, many properties

The idea of TriggerINK involves steps that smoothly flow into one another during the printing process. In the process, the various properties of the bio-ink come to light: "The aim is to print the bio-ink layercontinuously into the wound. It contains various ingredients that react to irradiation with light, for example. In this way, cross-links are created during the printing process that form a support framework and pores," explains Stefan Hecht, in whose laboratories such special light-sensitive building blocks are developed. What also happens during printing: guiding elements are instructed in which direction they should be aligned by using a low magnetic field. "The ink contains small gel rods with tiny magnetic particles. Therefore, the orientation of the guiding elements and ultimately the directional growth of the tissue can be controlled. The orientation direction inside the crosslinked bio-ink remains even when the magnetic field is removed again," adds Laura De Laporte. For the ink, the team will make use of a technology that Laura De Laporte has developed and patented: the so-called ANISOGEL for guided growth of nerve cells. Furthermore, the bio-ink will contain encapsulated growth factors and immune-modulating agents. "These can be released on demand at different times when required by ultrasound, and are thus designed to support the healing process," explains Andreas Herrmann. He is specialized in alternative systems for drug release and delivery. It is an ambitious and fascinating project that is entirely in line with the mission of the Leibniz Institute in Aachen, he concludes: to develop materials for a better life.


External partners and advisors


About the Werner Siemens Foundation (WSS)

The Werner Siemens Foundation (WSS) was founded in Schaffhausen in 1923 by Charlotte von Buxhoeveden and Marie von Graevenitz, née Siemens, the daughters of Carl von Siemens, who together with his brother Werner von Siemens had built up the later Siemens Group. The two founders were later joined by other family members as benefactors. The Werner Siemens Foundation, based in Switzerland, promotes outstanding innovations and talented young people in technology and the natural sciences in its philanthropic section.

Further information:


Further information
Member of the Scientific Board

Prof. Dr.-Ing. Laura De Laporte

+49 241 80-23309
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Portraitfoto Prof. Dr.-Ing. Laura De Laporte

Want to develop an alternative for replacing body tissues with TriggerINK (from left): Stefan Hecht, Laura De Laporte, Matthias Wessling and Andreas Herrmann

Stefanie Ratzke/DWI - Leibniz-Institut für Interaktive Materialien