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The increasing incidence of trauma in medicine brings with it new demands on the materials used for the surgical treatment of bone fractures. Titanium, its alloys, and steel are used worldwide in the treatment of skeletal injuries. These metallic materials, although inert, are often removed after the injured bone has healed. The second-stage procedure-the removal of the plates and screws-can overwhelm patients and overload healthcare systems. The development of suitable absorbable metallic materials would help us to overcome these issues. In this experimental study, we analyzed an extruded Zn-0.8Mg-0.2Sr (wt.%) alloy on a rabbit model. From this alloy we developed screws which were implanted into the rabbit tibia. After 120, 240, and 360 days, we tested the toxicity at the site of implantation and also within the vital organs: the liver, kidneys, and brain. The results were compared with a control group, implanted with a Ti-based screw and sacrificed after 360 days. The samples were analyzed using X-ray, micro-CT, and a scanning electron microscope. Chemical analysis revealed only small concentrations of zinc, strontium, and magnesium in the liver, kidneys, and brain. Histologically, the alloy was verified to possess very good biocompatibility after 360 days, without any signs of toxicity at the site of implantation. We did not observe raised levels of Sr, Zn, or Mg in any of the vital organs when compared with the Ti group at 360 days. The material was found to slowly degrade in vivo, forming solid corrosion products on its surface.
- MeSH
- fraktury tibie * metabolismus chirurgie MeSH
- hořčík chemie farmakokinetika farmakologie MeSH
- králíci MeSH
- lidé MeSH
- slitiny * chemie farmakokinetika farmakologie MeSH
- stroncium chemie farmakokinetika farmakologie MeSH
- testování materiálů * MeSH
- tibie metabolismus patologie MeSH
- vstřebatelné implantáty * MeSH
- zinek chemie farmakokinetika farmakologie MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Magnesium alloys show a good strength to weight ratio making them of interest for engineering applications in automotive and aerospace industry. However, the chemical reactivity of magnesium alloys causes problems with their corrosion and appropriate protective coatings should be applied on Mg components. On the other hand, the chemical reactivity of magnesium is desirable for biodegradable implants and for hydrogen storage. Magnesium alloys are considered as very promising materials in both of these areas. Advantages of Mg-based biodegradable implants, like fractured bone fixations, are good mechanical strength, corrodibility in the human environment, low toxicity and good compatibility with natural bone. Corrosion of magnesium in the human fluids produces hydrogen gas and alkalization of the surrounding environment. Neither of these products can be formed too fast, because it would slow down the healing process. Therefore, Mg-based alloys whose corrosion is slow in the human body are extensively investigated. Until now, both commercial engineering and qualitatively new alloys have been studied in the context of biodegradable implants. These alloys should not contain toxic, carcinogenic and allergic elements. Among the most promising biodegradable materials for bone fixations, Mg-Zn-Ca-(Y-RE) alloys were proposed recently. Magnesium hydride contains 7.6 wt.% of hydrogen, therefore, magnesium is also promising material for hydrogen storage. The main problem is in a high thermodynamic stability, i.e., in a high decomposition temperature, of the binary MgH2 hydride. Various attempts have been done to destabilize this phase. These include nano-crystalline structure, additions of transitions elements and catalysts. Hydrides based on Mg can be synthesized by the classical elemental synthesis or by a novel electrochemical hydriding
