Whereas conventional surface treatments using low-pressure or atmospheric pressure techniques have a limited penetration into the interior of bone implants, this new method makes it possible to apply a cell-growth-promoting coating to the interior of the implants using a plasma jet. The amino groups bond with the surface and ensure that bone cells find a convenient substrate to which they can adhere. A unique feature of the technique is that the 3D printing and coating processes go hand in hand and are combined in one device. Because no chemical pre-treatment with solvents is required for the coating, it is not only cost-effective, but also environmentally friendly.
The scaffold around which the implant is built is made from a special copolymer that is modelled on the natural bone. The 3D printing technique permits individual, precisely fitting design and stability.
Dr Jochen Borris, who heads up the Life Science and Ecology business unit at Fraunhofer IST, explains: “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.”
The mechanical stability of the implant can be controlled not only via the density of the printed scaffold structure, but also via special fillers that are added to the copolymer: the higher the filler concentration, the greater the stability.
Dr Thomas Neubert, manager of the EU project at Fraunhofer IST, added: “This development by our project partners from Maastricht University makes it possible to individually vary the stability inside the implant. Like natural bones, implants can now have areas with different strengths.”
Moreover, active drug ingredients such as antibiotics can be incorporated in the filler to reduce the risk of infection.
The project is currently at laboratory stage, but the team plans to modify the technique and bring it to maturity in the near future.