¾Ã²Ý¸£Àû

Magnesium, a remarkable metal! 

Unlike traditional implants such as titanium and stainless steel, magnesium offers distinct advantages. Its lower elastic modulus prevents stress shielding, reducing the risk of implant loosening. Another significant issue with the permanent metallic implants is the necessity of secondary surgery due to complications such as pain and patient demands. In children, permanent metallic implants remain close to the growing skeleton causing damage and constraints and it is generally believed that implants should be removed to prevent impairing the child’s bone growth.Yet, it's these limitations of permanent metallic implants that make magnesium truly stand out, owing to its exceptional biodegradable nature. Magnesium can degrade in our bodies over time, releasing essential magnesium ions necessary for human metabolism.

However, magnesium's rapid degradation can be a double-edged sword. Magnesium degrades too quickly, often leading to implant failure before complete bone healing. This project aims to harness the potential of CaP ceramic-based coatings to slow down degradation, enhance biocompatibility, and improve bone integration.

Developing magnesium-based orthopedic implants could eliminate the need for costly second surgeries to remove implants, reducing stress for both patients and doctors and significantly lowering the risk of infection. It's a groundbreaking step towards better orthopedic care.

Magnesium (Mg) and its alloys have been identified as a new generation of biodegradable metallic implants, attracting much attention due to their favourable biocompatibility, biodegradability, osteoconductivity, and mechanical properties. Biodegradable Mg implants have found their way into the clinics but are still not widely used. 

The uncontrollable corrosion of Mg alloys leads to a rapid reduction in mechanical integrity which limits their clinical application. Surface modification through the application of bioactive coatings has been proposed as an efficient and cost-effective route to reducing the corrosion rate, and hence the degradation rate, of Mg-based medical implants. The relationships between constituent chemicals, processing conditions, digestion time and immersion cycles were investigated to optimise the phase composition, coating thickness and mechanical integrity to Mg substrate. Subsequently, the corrosion behaviour was evaluated using potentiodynamic polarisation methods, gravimetric analysis, ion release, and hydrogen evolution rate as a function of CaP coating. Biological studies were also conducted to assess the biocompatibility and osteoconductive properties. The electrochemical measurements indicated that the dual-layer CaP coating reduced the corrosion rate of uncoated Mg by eight-fold. The corrosion rate calculated by gravimetric analysis and hydrogen evolution also showed that DCPD-OCP-coated Mg specimens exhibited the lowest tendency towards corrosion.

Taken together the results demonstrate that the proposed CaP coating technology could provide many opportunities for the more widespread use of Mg-based medical implants for orthopaedic applications.

Great to see this research project progressing to an important result for clinical benefit in the area of Trauma and Orthopaedics. Fixing compromised bone fractures is an ever increasing problem for surgeons today and advanced material combinations that work with the patients built in healing mechanisms is the key to success. At @PBC Biomed we are currently developing a number of advanced bone replacement therapies and look forward to bringing this one to the clinic soon.

Dr. Gerard Insley

Chief Science Officer, PBC Biomed

This project encompasses two key strategies with significant implications for patient outcomes and the orthopedic industry. The implementation of Additive Manufacturing (AM) for magnesium (Mg) scaffold fabrication offers the potential to create customized interconnected porous metal scaffolds with vastly improved mechanical and biological properties compared to conventional methods. A distinctive feature of this approach is the ability to design personalized implants tailored to anatomical geometries, leading to enhanced results and reduced treatment costs. Furthermore, the streamlined production process, with the elimination of multiple stages of conventional machining, makes batch processing not only feasible but also economically advantageous.

The second strategy involves the use of bioactive calcium phosphate coatings to enhance the corrosion resistance of Mg. This significantly extends the longevity of orthopedic implants, resulting in a reduced need for implant replacements and associated surgeries. This translates to cost savings for healthcare providers and a markedly improved quality of life for patients. By reducing the corrosion rate of Mg-based orthopedic implants, their range of applications is substantially broadened, affording new possibilities for patient care in a wider array of clinical scenarios, thereby benefiting individuals who may have previously faced limitations in their treatment options.

Biography

Tina is a PhD researcher at Dublin City University, specializing in the development of magnesium-based medical implants for orthopedic applications. She earned her master's degree in Biomedical Engineering from Islamic Azad University Science and Research Branch, Iran. Before commencing her doctoral studies, Tina served as an engineer at a Research Centre for Science and Technology in Medicine, affiliated with Tehran University of Medical Sciences (TUMS). During this period, she focused on designing patient-specific instruments (PSI) for osteotomy and total knee replacement surgery, tailored for specific implant use.

In 2021, Tina embarked on her PhD journey at Dublin City University within the Advanced Metallic Centre for Doctoral Training PhD program. Her primary research interests revolve around the utilization of metals in orthopedic applications.