Institute of Metallic Biomaterials
Human life expectancy is increasing, and more and more people go in for high-risk sports. Against this background, the Institute of Metallic Biomaterials develops novel materials for medical implants based on titanium and magnesium. One target is to improve biocompatibility of permanent titanium implants by developing non-toxic alloys and adapting the materials to the mechanical properties of the bone. Another focus is laid on magnesium alloys that degrade over time in the body. By adding pharmaceutically active elements, such as antimicrobial silver, to the alloys novel regenerative or therapeutic effects are intended to become effective during magnesium degradation. Our work covers the entire process chain, including studies in animal models as well as the intensive utilization of in situ methods.
Successful Completion of DFG Project OAMag: New Insights into Mg Particles in Osteoarthritis Therapy
graphical abstract DFG project OAMag
Osteoarthritis (OA) significantly affects synovial joints, including cartilage and subchondral bone. Biomaterials that can slow OA progression offer a promising alternative or supplement to anti-inflammatory and surgical treatments. As part of the DFG project “OAMag Therapy”, we explored the use of magnesium (Mg) microparticles, known for their bone regeneration potential, in tissue regeneration and OA prevention.
We used in vitro assays with mesenchymal stem cells to evaluate the compatibility and function of Mg microparticles. The biocompatibility tests showed 90% cell viability at concentrations below 10 mM after 3 days. The assays revealed that Mg degradation products help differentiate mesenchymal stem cells. Particularly noteworthy was the reduction in the release of inflammatory markers by the Mg particles. In addition, an induction of the expression of extracellular matrix proteins and indicator proteins of bone formation was observed.
Our study suggests that Mg microparticles have therapeutic potential for OA treatment by supporting bone and cartilage repair, even under inflammatory conditions.
Chathoth et al., J Biomed Mater Res 2025 113: e37862
Metadata for nano-CT images fully semantically annotated
What does this image show?
This question is hard to answer in isolation. Only with the associated metadata can it be recognised as a wire made of Mg-2Ag, 80 µm in diameter, degraded in Simulated Body Fluid for 3.8 hours, and imaged in situ using synchrotron-based nano-CT.
The semantic annotation of the metadata defines terms and illustrates their relationships. This structured approach allows for complex conclusions and enables other researchers to use the data. For our electronic lab book Herbie, we have developed a template that automates the semantic annotations of nano-CT images, based on the metadata schema from the Joint Lab MDMC.
Kirchner et al. 2025 (preprint)
Prof. Dr. Berit Zeller-Plumhoff Appointed Acting Head of the Institute of Metallic Biomaterials
We are pleased to announce that Prof. Dr. Berit Zeller-Plumhoff has taken on the interim leadership of the Institute of Metallic Biomaterials part-time as of January 1, 2025. Prof. Dr. Zeller-Plumhoff, who previously led the department MBS, has since become Professor for Data-driven Analysis and Design of Materials at the Faculty of Mechanical Engineering and Marine Technology at the University of Rostock.
In her new role, Prof. Dr. Zeller-Plumhoff will manage the institute alongside her demanding position in Rostock until Prof. Dr. Regine Willumeit-Römer returns from her position as interim manager of Hereon.
We are confident that Prof. Dr. Zeller-Plumhoff will lead the institute with great success and dedication and look forward to the continued progress and scientific achievements under her leadership.
MB at the German Congress of Orthopaedics and Traumatology 2024
MB exhibition stand at DKOU (from left to right: Dr. Vasyl Haramus, Dr. Heike Helmholz, Dr. Domonkos Tolnai, Dr. Thomas Ebel, Prof. Dr. Norbert Hort)
This year's German Congress for Orthopaedics and Trauma Surgery, by its own account "the most important congress in the field of orthopaedics and trauma surgery in Germany and also the largest in this field in Europe", took place in Berlin from 22 to 25 October. We took the opportunity to present our Mg-based biomaterials and their manufacturing processes to orthopaedic surgeons, medical students and representatives of the implant manufacturing and distribution industry.
In addition to the well-attended trade fair, there were exciting presentations on the treatment and tissue regeneration of bone fractures and joint diseases. New biomaterials were also a topic, as were the consequences of periprosthetic infections and other concomitant diseases. A special industry session was dedicated to the use of Mg implants.
website German Congress of Orthopaedics and Traumatology
Advances in bone healing: progress with Ti-Mg hybrid implants
Electron micrograph of the interface between magnesium (Mg) and titanium (Ti) part, including PEO coating. It can be seen how the coating extends over both materials
Hybrid implants, combining a dissolvable part and a permanent part, show promise for improving bone healing after accidents or illnesses. The permanent part provides stabilization, while the dissolvable part compensates for bone defects and promotes regeneration. Titanium and magnesium are particularly suitable materials for this purpose.
Previous experiments at the Institute have demonstrated that sintering techniques effectively join these materials. However, the accelerated degradation of magnesium due to its bond with titanium remains a challenge. In collaboration with the Institutes of Surface Science and Materials Physics, a potential solution has been identified: applying a plasma electrolytic oxidation (PEO) layer to a sintered Mg-Ti specimen. This coating evenly covers and protects both parts, significantly reducing degradation without completely preventing dissolution. High-resolution synchrotron tomography revealed that the PEO layer's internal structure depends on the underlying material.
Further experiments are needed, but these promising results represent a step towards hybrid implants.
Fazel et al., Journal of Magnesium and Alloys 2024 12(8):3142-3158
CAU, Hereon and UKSH agree on cooperation for digital implant research
Kiel University (CAU), the Helmholtz Centre Hereon and the University Medical Centre Schleswig-Holstein (UKSH) are joining forces in the field of digital implant research. The aim of this interdisciplinary project is to take implant development to a new level by combining biomaterial research, data science, AI and medical research.
Confident and full of anticipation after the successful founding symposium on 10 June 2024 in Kiel: The members of the founding team (from left to right) Prof. Cyron, Prof. Checa, Prof. Jansen, Prof. Saalfeld, Prof. Deuschl, Prof. Willumeit-Römer and Prof. Quandt. Further founding team members (not pictured): Prof. Tomforde and Prof. Popp.
Prof. Dr. Regine Willumeit-Römer, co-initiator of the collaboration and Director of the Institute for Metallic Biomaterials at Hereon: "The future of implant development lies in the use of computer simulation models and artificial intelligence, which map the complicated development cycle from material to tissue regeneration and ultimately flow into the authorisation process. In this way, existing implants can be improved and further developed into personalised implants based on individual, molecular body characteristics." The research centres on digital twins that depict physiological and material science conditions in computer models.
With the help of these digital twins, new implants are no longer developed at the workbench, but on a high-performance computer and are no longer heuristically acceptable, but comprehensively optimised to meet medical needs.
The contribution of the Institute of Metallic Biomaterials lies in the provision of data on Mg-based and thus degradable implants in a biological environment, the realisation of corresponding experiments and simulations. Prof Willumeit-Römer also acts as project coordinator.
DAAD Rise scholarship holder Janice Xie at MBB
Janice Xie (Photo: Heike Helmholz)
Janice Xie is a student at Northwestern University in Illinois, USA, studying materials science and engineering with a focus on biomaterials. During her time with us, she researches the foreign body reaction on Mg-Li alloys.
more (Intranet Hereon)
Successful 3D printing of bone regeneration structures made of magnesium
Open lattice structures made of magnesium using sinter-based 3D printing. The experimentally measured mechanical compressive strength agrees with simulation calculations.
The use of open lattice structures can be useful for the treatment of bone defects caused by illness or accidents. They immediately stabilize the surrounding tissue and serve as a support for new bone formation during the healing process, similar to a trellis in a plant bed. The combination of degrading magnesium with the possibilities of 3D printing enables the patient-specific production of temporary implants adapted to the defect. Ideally, pure, healthy bone will replace the defect once the lattice has dissolved. In addition, 3D printing allows the mechanical properties to be precisely adapted to the required load-bearing capacity at the defect site through the choice of structure in order to further promote bone healing.
In this study, such a structure was successfully produced for the first time using sinter-based 3D printing (Fused Granular Fabrication) from a magnesium-gadolinium alloy. The experimentally determined mechanical properties were compared with the results of a computer simulation (finite element model) and showed good agreement. This provides the basis for geometrically and mechanically adapted bone regeneration materials.
Wolff et al., JMA 2023 11(8):2750-2762
Bridging the gap between in vitro and in vivo degradation rates for Mg-xGd implants
The degradation rate calculated using the surrogate model in comparison to the experimental data. Volume renderings are inserted for samples after 4 and 8 weeks of degradation
Is it possible to predict in vivo degradation of magnesium implants based on their in vitro degradation? In our recent publication “Utilizing Computational Modelling to Bridge the Gap between In Vitro and In Vivo Degradation Rates for Mg-xGd Implants”, we built a surrogate model that is trained on a more computationally expensive computer model. By calibrating the surrogate model to datasets from in vitro and in vivo degradation of magnesium-based screws, we have been able to find a parameter with which we can map one to the other. In this case, we can link the diffusion rates of Mg2+ ions in the different systems. In the future, it may become possible to estimate degradation rates in vivo by leveraging such links between diffusion rates derived from in vitro and in vivo experiments through surrogate models. This enables to draw conclusions about in vivo degradation rates solely from in vitro experiments.
Al Baraghtheh et al., Corros. Mater. Degrad. 2023 4(2):274-283
Progress in Application-Oriented Sintering Simulation
Simulation of the sintering of a powder cube. The new model realistically describes the coalescence of the powder particles, which leads to a change in the size of the cube (left: initial configuration, t = 0s, right: final configuration, t = 5000s)
Sintering is the central process in the manufacturing techniques used at the institute to produce a solid, ready-to-use implant from loose metal powders. The powder particles grow together at high temperatures and an almost dense material is created. The alloy, powder form, powder size, temperature and time play a critical role in the properties of the final implant. Today, even in industry, optimized process parameters are often determined in complex test series that cost time and money. There is therefore great interest in using computer simulations to reduce this effort and calculate optimum sintering parameters to achieve the desired implant properties without the need for experimental test series.
Together with the Institute for Material Systems Modeling, such an application-oriented sintering model is being developed. In a recent study, a decisive step was taken to perform physically accurate calculations in an acceptable computing time. In particular, a problem inherent in many existing sintering models was eliminated, namely that the component does not shrink in the simulations, which it does in reality. A new approach combines a “7DOF” (7 degrees of freedom) model developed at Hereon with a discrete element method model. While the former calculates the material movements between the various powder particles with little computational effort, the latter models the forces that occur and the associated change in shape. Comparisons with experimental data showed good agreement.
Ivannikov et al., Comp. Part. Mech. 2023 10:185–207
Publication selected as Editor’s Choice: In Situ Synchrotron Diffraction Study of Compression of AZ91 Composites Reinforced with Recycled Carbon Fibres
Macroscopic true strain (left), strain on lattice planes (centre), and intensity (right) against true stress for AZ91/C100/5f in as extruded state
Sustainability is an important consideration for manufacturers. One approach to improve on sustainability in the automotive and aerospace industries is to improve fuel efficiency by using lightweight materials. Magnesium is a promising candidate for these applications as it is lightweight, has a high specific strength, good machinability and castability. Alloying additions can further improve these properties as well as improving corrosion resistance and ductility. Metal-matrix composites (MMCs) using an Mg alloy matrix offer improved mechanical properties, whilst retaining Mg alloys’ light mass. Sustainability can also be considered when choosing the reinforcing addition. Recycled carbon fibres (rCFs) recovered from carbon-fibre-reinforced polymers maintain many of the mechanical properties of virgin CFs, but are cheaper and less energy intensive to produce. Finding uses for rCFs will also encourage more commercial recycling of carbon fibre reinforced composite materials. The colleagues of our Institute, with partners from the Institute of Material and Process Design and the University of Cambridge, utilized synchrotron radiation diffraction to understand how the heat treatments and CF reinforcement affect the active deformation mechanisms during to develop high-performance, sustainable composite materials. The corresponding publication has been selected as an Editor’s Choice Article in Crystals.
Mance et al., Crystals 2022 12(11):1502
Helmholtz Imaging Best Scientific Image Contest 2023: 1st Place in the category participants choice award
Magnesium Watercolour Whirl by Sarkis Gavras (Hereon)
Sarkis Gavras won the first place of Best Scientific Image Contest 2023 in the category “Participants’ Choice Award” with his image of a Magnesium Watercolour Whirl. This polarized light optical image shows a magnesium alloy with a colorful array of small grains, which have formed along the edge of a swirl shaped pore.
Best Scientific Image 2023
Structure and Mechanics of Bone Depend on Implant Materials
How do we study the behavior of bone implants under load in a realistic environment that responds to the implanted material? In our recent publication “On the material dependency of peri-implant morphology and stability in healing bone” the imaging capabilities of the beamlines operated by Hereon at DESY were combined with a miniaturized loading cell and high-performance digital volume correlation software to answer such questions with 4D imaging.
We were able to visualize the strains in the bone surrounding several screw implants experimentally on the micrometer scale. The study demonstrates that these strains and the morphological parameters that are relevant to the expected implant stability depend on the biomaterial deployed. Thus, we expect that the choice of material for the bone implant of the future will not just be a choice between one or two materials but depend heavily on the shape of the fracture and patient bone health.
Bruns et al., Bioactive Materials 2023 28:155-166
Rendering of bone deformation determined from a push-out sequence. Color indicates the deformation magnitude.
Magnesium: Solutions in Medicine
videos and further links
Press release 12.10.2021
MgSafe was an EU project in which 15 doctoral students in eight different countries were working on developing and improving imaging techniques for biodegradable magnesium implants.
MgSafe - X-ray vision in 360°