Research

Fraunhofer IST researchers develop 3D printing plasma jetting method for bone implants

Researchers at the Fraunhofer Institute for Surface Engineering and Thin Films IST have developed a method using cold plasma to 3D print patient-specific plastic bone implants.

As part of the EU-funded research and innovation project “FAST”, which stands for “Functionally graded Additive Manufacturing (AM) scaffolds by hybrid manufacturing,”  the German research institute as well as seven European partners sought to create a new 3D printing technology which manufactures customized implants to be precisely fitted into a patient’s bone.

“Our goal is for the bone cells to grow into the synthetic structure as quickly as possible and finally replacing the implant which is broken down gradually by the body’s own enzymes,” explained Dr. Jochen Borris, head of the Life Science and Ecology business unit at Fraunhofer IST.

Plasma-jet coating of medical implant scaffolds. Photo via Fraunhofer.
Plasma-jet coating of medical implant scaffolds. Photo via Fraunhofer.

3D printing bone-forming cells

According to Fraunhofer IST, cancerous tumors, infections, and bad fractures commonly prompt for the surgical removal of bones and insertion of implants. The method developed by the partners enables the application of a cell-growth-promoting coating to the interior of additively manufactured layers of bone implants with plasma jetting.

The amino groups within the coating bond the surface and ensures that bone cells find a “convenient substrate.” The process is unique as it combines both 3D printing and coating techniques in one device. Furthermore, this method is said to be cost-effective as no chemical pretreatment with solvents is required for the coating.

The plasma jetting process for manufacturing coated scaffolds. Immediately after extrusion, the scaffold structures are treated with a cold plasma. Image via Fraunhofer.
The plasma jetting process for manufacturing coated scaffolds. Immediately after extrusion, the scaffold structures are treated with a cold plasma. Image via Fraunhofer.

This cold plasma jetting method was created due to the limitations of conventional surface treatments. Within these treatments, which use low-pressure or atmospheric pressure techniques, the researchers found there to be limited penetration into the interior of bone implants.

“We’re currently working on simplifying the process and making it more stable,” added Dr. Borris. “To be able to further pursue development and carry out clinical studies, we’re on the search for industrial partners.”

“With our method, we’re able to control the shape, porosity, mechanical stability, and biomechanical characteristics well and vary them within the implants. This means that we can produce areas with different strengths or porosities, which can also be coated with various functional groups.”

The partners, including Abalonyx, Fundacion Tecnalia Research & Innovation, GeSIM, Maastricht University, PolyVation, Prolabin & Tefarm and University of Padova, believe their method can equip medical professionals with strong, patient-specific, biocompatible implants.

Technical coatings for additive manufacturing

Elsewhere, in a joint project, researchers from Sirris, a non-profit scientific organization in Belgium and the Fraunhofer Institute for Applied Polymer Research IAP have investigated technical coatings for additive manufacturing (TCAM). 

“With the transition from rapid prototyping to industrial production, the demands on AM-manufactured components are growing. Being able to warrant consistent material quality is essential for industry producers. In addition, demands on the surface quality are growing,” said Dr. Andreas Holländer, an expert in surface technology at the Fraunhofer IAP.

As a result of the project, the researchers significantly improved the surface roughness and porosity of 3D printed parts using lacquering and polishing. Moreover, the scientists metalized the smoothed components which improved scratch resistance and antimicrobial properties. Dr. Holländer added:

“It is important that every part of the component’s surface has the required quality. In complicated parts, some surfaces are difficult to reach. With the appropriate surface treatment technology, which in future will even be integrated into the AM machines, we are able to functionalize even complex components completely.”

Complex 3D printed parts dry after their metallization. Photo via Fraunhofer IAP.
Complex 3D printed parts dry after their metallization. Photo via Fraunhofer IAP.

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Featured image shows the plasma-jet coating of medical implant scaffolds. Photo via Fraunhofer.