Dr. Moritz, 3D printing is no longer unique. Now you have developed a new process to print medical components. What is new about this?
Tassilo Moritz: What makes it so unique is the material class. Commercialized 3D printing involves polymers and metal parts. We are working with ceramic products and things are very different in this area. So far, there is only one commercialized manufacturing process for dense ceramic parts, which is lithography-based ceramic manufacturing. However, the method we are currently developing is thermoplastic 3D printing. We are focusing on a suspension-based additive manufacturing method to produce ceramic components. Unlike powder bed printing, the benefit of suspension-based manufacturing is the higher homogeneous particle density within a suspension. This method allows us to create very dense components; the density we are able to achieve is above 99 percent.
For which medical technology areas is this process particularly well suited?
Moritz: Personalized, customized implants for knee joints for example, but also implants in the jaw area are conceivable applications. You can also produce medical instruments using this process. Within the EU ”CerAMfacturing“ project, for example, we started to make personalized microsurgical parts such as grippers and pincers from ceramic that play a role in laparoscopic or keyhole surgery. Surgeons often want adapted instruments to be able to better adjust to the physical requirements of patients. Having said that, one could also consider custom grips for surgeons that allow for a better fit of the tool in the surgeon’s hand.
Section through an additively manufactured ceramic microreactor: The complex ducting and the fluidic connections at the top were printed with the component; & Copy; Photo Fraunhofer
You also printed a microreactor using additive manufacturing technology. What exactly is that?
Moritz: The advantage of microreaction technology is that you are able to work with very expensive or dangerous chemicals on a very small scale; I am referring to a microliter scale here. This opens up brand-new opportunities in the area of research and development. However, using a micromixer, our vision is to be able to administer a medication combination that’s tailored to patients at the hospital bed and that patients are able to “control” by themselves. That means, measurements such as blood pressure, blood sugar or heart rate are taken to automatically administer the appropriate medicine if necessary. It would be mixed in the micromixer based on the measured values.
The condyles of the knee can be printed accurately modeled. This creates personalized prostheses; & Copy; Photo Fraunhofer
In other words, you would be able to prepare the applicable medication combination tailored to a patient’s current state. The advantage of this type of ceramic system is that you can also pour in even chemically aggressive substances and that the component can be sterilized. There is no problem placing the component into a 400 °C oven after use and be able to subsequently reuse it again. What’s more, it is very small, about the size of a two euro coin. Ceramic microreactors or micromixers can generally be used for various types of fluid-based chemical reactions.
How big or how small are you presently able to print?
Moritz: The limitation is currently dictated by the size of the available space. In the case of thermoplastic additive manufacturing, the current dimension limits are approximately 20 by 20 by 10 up to 20 centimeters. We achieve a minimum resolution of approximately 300 micrometers.