Zn-(0-1.6)Mg (in wt.%) alloys were prepared by hot extrusion at 300 °C. The structure, mechanical properties and in vitro biocompatibility of the alloys were investigated. The hot-extruded magnesium-based WE43 alloy was used as a control. Mechanical properties were evaluated by hardness, compressive and tensile testing. The cytotoxicity, genotoxicity (comet assay) and mutagenicity (Ames test) of the alloy extracts and ZnCl2 solutions were evaluated with the use of murine fibroblasts L929 and human osteosarcoma cell line U-2 OS. The microstructure of the Zn alloys consisted of recrystallized Zn grains of 12 μm in size and fine Mg2Zn11 particles arranged parallel to the hot extrusion direction. Mechanical tests revealed that the hardness and strength increased with increasing Mg concentration. The Zn-0.8 Mg alloys showed the best combination of tensile mechanical properties (tensile yield strength of 203 MPa, ultimate tensile strength of 301 MPa and elongation of 15%). At higher Mg concentrations the plasticity of Zn-Mg alloys was deteriorated. Cytotoxicity tests with alloy extracts and ZnCl2 solutions proved the maximum safe Zn(2+) concentrations of 120 μM and 80 μM for the U-2 OS and L929 cell lines, respectively. Ames test with extracts of alloys indicated that the extracts were not mutagenic. The comet assay demonstrated that 1-day extracts of alloys were not genotoxic for U-2 OS and L929 cell lines after 1-day incubation.
- MeSH
- biokompatibilní materiály chemie toxicita MeSH
- hořčík chemie toxicita MeSH
- kultivované buňky MeSH
- lidé MeSH
- myši MeSH
- nádorové buněčné linie MeSH
- poškození DNA účinky léků MeSH
- slitiny chemie toxicita MeSH
- viabilita buněk účinky léků MeSH
- zinek chemie toxicita MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
There has recently been an increased demand for porous magnesium materials in many applications, especially in the medical field. Powder metallurgy appears to be a promising approach for the preparation of such materials. Many works have dealt with the preparation of porous magnesium; however, the effect of sintering conditions on material properties has rarely been investigated. In this work, we investigated porous magnesium samples that were prepared by powder metallurgy using ammonium bicarbonate spacer particles. The effects of the purity of the argon atmosphere and sintering time on the microstructure (SEM, EDX and XRD) and mechanical behaviour (universal loading machine and Vickers hardness tester) of porous magnesium were studied. The porosities of the prepared samples ranged from 24 to 29 vol.% depending on the sintering conditions. The purity of atmosphere played a significant role when the sintering time exceeded 6h. Under a gettered argon atmosphere, a prolonged sintering time enhanced diffusion connections between magnesium particles and improved the mechanical properties of the samples, whereas under a technical argon atmosphere, oxidation at the particle surfaces caused deterioration in the mechanical properties of the samples. These results suggest that a refined atmosphere is required to improve the mechanical properties of porous magnesium.
- MeSH
- biokompatibilní materiály chemie MeSH
- difuze MeSH
- hořčík chemie MeSH
- hutnictví metody MeSH
- kovové nanočástice chemie ultrastruktura MeSH
- pevnost v tlaku MeSH
- plazmové plyny chemie MeSH
- poréznost MeSH
- povrchové vlastnosti MeSH
- prášky, zásypy, pudry MeSH
- testování materiálů MeSH
- tvrdost MeSH
- vysoká teplota MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The demand for porous biodegradable load-bearing implants has been increasing recently. Based on investigations of biodegradable stents, porous iron may be a suitable material for such applications. In this study, we prepared porous iron samples with porosities of 34-51 vol.% by powder metallurgy using ammonium bicarbonate as a space-holder material. We studied sample microstructure (SEM-EDX and XRD), flexural and compressive behaviors (universal loading machine) and hardness HV5 (hardness tester) of the prepared samples. Sample porosity increased with the amount of spacer in the initial mixtures. Only the pore surfaces had insignificant oxidation and no other contamination was observed. Increasing porosity decreased the mechanical properties of the samples; although, the properties were still comparable with human bone and higher than those of porous non-metallic biomaterials and porous magnesium prepared in a similar way. Based on these results, powder metallurgy appears to be a suitable method for the preparation of porous iron for orthopedic applications.
Porous magnesium-based materials are biodegradable and promising for use in orthopaedic applications, but their applications are hampered by their difficult fabrication. This work reports the preparation of porous magnesium materials by a powder metallurgy technique using ammonium bicarbonate as spacer particles. The porosity of the materials depended on the amount of ammonium bicarbonate and was found to have strong negative effects on flexural strength and corrosion behaviour. However, the flexural strength of materials with porosities of up to 28 vol.% was higher than the flexural strength of non-metallic biomaterials and comparable with that of natural bone.
- MeSH
- hořčík chemie MeSH
- hutnictví metody MeSH
- hydrogenuhličitany chemie MeSH
- koncentrace vodíkových iontů MeSH
- koroze MeSH
- mikroskopie elektronová rastrovací MeSH
- poréznost MeSH
- prášky, zásypy, pudry MeSH
- spektrometrie rentgenová emisní MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
As-cast Mg-Sn, Mg-Ga and Mg-In alloys containing 1-7 wt.% of alloying elements were studied in this work. Structural and chemical analysis of the alloys was performed by using light and scanning electron microscopy, energy dispersive spectrometry, x-ray diffraction, x-ray photoelectron spectroscopy and glow discharge spectrometry. Mechanical properties were determined by Vickers hardness measurements and tensile testing. Corrosion behavior in a simulated physiological solution (9 g/l NaCl) was studied by immersion tests and potentiodynamic measurements. The cytotoxicity effect of the alloys on human osteosarcoma cells (U-2 OS) was determined by an indirect contact assay. Structural investigation revealed the dendritic morphology of the as-cast alloys with the presence of secondary eutectic phases in the Mg-Sn and Mg-Ga alloys. All the alloying elements showed hardening and strengthening effects on magnesium. This effect was the most pronounced in the case of Ga. All the alloying elements at low concentrations of approximately 1 wt.% were also shown to positively affect the corrosion resistance of Mg. But at higher concentrations of Ga and Sn the corrosion resistance worsened due to galvanic effects of secondary phases. Cytotoxicity tests indicated that Ga had the lowest toxicity, followed by Sn. The most severe toxicity was observed in the case of In.
- MeSH
- biokompatibilní materiály chemie farmakologie MeSH
- buněčná smrt účinky léků MeSH
- fotoelektronová spektroskopie MeSH
- koroze MeSH
- kovy farmakologie MeSH
- lidé MeSH
- mechanické jevy účinky léků MeSH
- mikroskopie elektronová rastrovací MeSH
- nádorové buněčné linie MeSH
- pevnost v tahu účinky léků MeSH
- potenciometrie MeSH
- slitiny chemie farmakologie MeSH
- testování materiálů * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
