Production technologies for medical engineering

For the development of new medical products, more and more novel technologies are applied, complementing the conventional production processes. The Fraunhofer IPT is developing manufacturing technologies and process chains for medical engineering applications, e.g. the production of surgical instruments and implants.

Customized implant production using machining processes

Each human being is different – this applies not only to character and personality but also to individual body parts and bones. The technologies used to manufacture the customized implants which permit treatment matching the specific requirements of the patient, need to be flexible and efficient. The Fraunhofer IPT provides support in designing and implementing flexible, high-performance machining processes. We work with our clients to develop flexible process technology platforms, which permit the production of tailored implants such as tooth structures, bone plates as well as hip and knee implants reproducibly and swiftly. Adapting the process technology to suit new materials such as titanium-based alloys or cobalt-chromium steel is one of the main elements in our work.

Bioprinted 3D-scaffolds to support osseointegration of implants

© Fraunhofer CMI

Beyond the mechanical cues provided by engineered surfaces, the body also requires biological cues that appropriately trigger healing and new growth. While several tissues in the human body can self-repair small wounds, there is an urgent need for materials that can replace large defects and for implants that thoroughly integrate seamlessly into the tissue. Our partners at Fraunhofer CMI in Boston, USA have developed a bioprinter that can precisely deposit biomimetic hydrogels into 3D architectures that address these needs. The bioprinter is multi-scale and multi-material, allowing the user the versatility of up to five simultaneous bioink lines. The printing lines and environment are temperature controlled enabling bioprinting of viable cells within the fabricated support material. This application allows for accurate printing of such tissues as blood vessel models in which human endothelial cells are printed along the inner layer of a mesenchymal cell cylinder. Additional applications are generating special coatings for titanium implants in which the bioprinted scaffold signals migrating bone-producing cells (osteoblasts) to deposit new mineral and potential new bone growth. These osseoinductive scaffolds can be bioprinted and grafted directly onto the titanium architectures manufactured by Fraunhofer IPT. Together, these technologies work in tandem to give the cells the molecular and mechanical cues needed to form a tight adhesive bond between bone and implant.

Biocompatible implants and prostheses

Components made of fiber-reinforced plastics are prized in MRI for their freedom from artefacts, and for their x-ray transparency, autoclavability, biocompatibility and excellent mechanical characteristics in a diverse range of medical engineering sectors. Examples of their uses include implants, operating instruments and spring elements for prostheses. We are developing both fiber-reinforced composite parts and components made of hybrid material composites for use in medical products. In years of experience in the application of fiber composite components for medical engineering, we have built up the expertise required to conduct thorough feasibility analyses for new applications and to deal effectively with special requirements relating to innovative medical products. To this end, we develop innovative production processes, capable of processing all fiber and matrix materials in common use, including high-performance polymers such as PA and PEEK. In addition to component design and production, our services include the application of a wide range of testing methods to qualify part qualities.

Minimally invasive MR-compatible and customized instruments

Rapid advances in imaging methods have resulted in a sharp increase in the number of minimally invasive medical procedures in recent years. On-going miniaturization in conjunction with the integration and the combination of additional functions in specialized instruments are important areas of development. Nevertheless, the range of operating tools available is frequently very limited and includes only standard tools. These must be adapted to match as closely as possible the specific requirements of the operating surgeon if they are to impact positively on the success of operations. The Fraunhofer IPT has developed new production process chains which help to close the gap between the efficient manufacture of wholly standardized medical products and customized ones. We can support your company in developing the concept, designing, producing, testing and licensing of new, minimally invasive medical products. Our strengths lie in the miniaturization of components, particularly those made of fiber composite materials and in the integration of optical components such as sensor technology and laser systems.

Surface structuring and functionalization

Surface characteristics play a significant role in numerous applications in medical engineering: Targeted functionalization can prevent the growth of germs, improve the engraftment of implants or modify the wettability of the surfaces. At the Fraunhofer IPT we have extensive expertise in a diverse range of surface structuring and production processes for 2D and 3D structures in the micro and nanometer ranges:

Diamond cutting

The micro- and nanotopographies of a surface influence a number of its characteristics, such as rheology (flow behavior), tribology (friction) or adhesion (bonding). We modify the flow properties of a micro-fluidic system or increase the efficiency of cell cultivation, for example, by using diamond tools to give surfaces precisely defined structures. Similarly, the optical characteristics of a material can be modified for analysis purposes by directing light through microprisms, for instance.  When discreet surface structures are applied to components or die inserts, surface roughness (Ra), can be in the low, single-digit nanometer range, depending on the production process involved. Any surface geometry, from a flat surface to a highly curved, three-dimensional surface can be produced using diamond cutting processes.

Laser structuring

At the Fraunhofer IPT, we also deploy laser structuring as a flexible means of functionalizing surfaces: micro- and nanostructures can be incorporated into a virtually unlimited range of materials, thereby optimizing wettability properties, for example. Lateral structure sizes in excess of 10 µm can be achieved via direct laser structuring. Even smaller, periodic structures with dimensions as small as 100 nm can be achieved via self-organizing structuring. Parts with complex shapes can be processed in a fully digital, laser structuring process chain, using a 5+4-axis machine.

Two-photon polymerization

Two-photon polymerization is a generative process for the production of three-dimensional plastic structures with sub-micrometer resolution. The high degree of freedom means that there are no restrictions on the structural design. Consequently, highly complex, individual geometries can be created which would be inconceivable if cutting and conventional lithographical processes were used. The resolution of the process is 150 nm laterally and approx. 400 nm axially. Speeds in excess of 10,000 µm/s are achieved using a galvanometer scanner.