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Magnesium-based composites with improved in vitro surface biocompatibility.

Huan Z, Leeflang S, Zhou J, Duszczyk J - J Mater Sci Mater Med (2010)

Bottom Line: In this study, bioactive glass (BG, 45S5) particles were added to a biodegradable magnesium alloy (ZK30) through a semi-solid high-pressure casting process in order to improve the surface biocompatibility of the biomaterial and potentially its bioactivity.SEM, EDX and EPMA showed the retention of the morphological characteristics and composition of BG particles in the as-cast composite materials.In vitro tests in a cell culture medium confirmed that the composites indeed possessed an enhanced ability to induce the deposition of a bone-like apatite layer on the surface, indicating an improved surface biocompatibility as compared with the matrix alloy.

View Article: PubMed Central - PubMed

Affiliation: Department of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, 2628 CD, Delft, The Netherlands.

ABSTRACT
In this study, bioactive glass (BG, 45S5) particles were added to a biodegradable magnesium alloy (ZK30) through a semi-solid high-pressure casting process in order to improve the surface biocompatibility of the biomaterial and potentially its bioactivity. The observation of the as-cast microstructures of ZK30-BG composites indicated homogeneous dispersion of BG particles in the matrix. SEM, EDX and EPMA showed the retention of the morphological characteristics and composition of BG particles in the as-cast composite materials. In vitro tests in a cell culture medium confirmed that the composites indeed possessed an enhanced ability to induce the deposition of a bone-like apatite layer on the surface, indicating an improved surface biocompatibility as compared with the matrix alloy.

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Distribution of Si in the composite as determined by EPMA. The analysis area on a ZK30-BG MMC sample is indicated by the square in the Backscattered Electron Image (BEI). The intensity of the Si Kα in the framed area is represented by the gray scale (or a jet-like colour scheme in the online version). Here black represents a low signal and light gray-white higher intensity signals (pinkish-white the highest intensity in the online version)
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Fig4: Distribution of Si in the composite as determined by EPMA. The analysis area on a ZK30-BG MMC sample is indicated by the square in the Backscattered Electron Image (BEI). The intensity of the Si Kα in the framed area is represented by the gray scale (or a jet-like colour scheme in the online version). Here black represents a low signal and light gray-white higher intensity signals (pinkish-white the highest intensity in the online version)

Mentions: Since the biomedical property of a bioactive ceramic material is closely related to its chemical composition, it is of utmost importance to keep the compositional characteristics of BG particles in the composite unchanged [18]. In general, it is rather difficult to ascertain the retention of the chemical composition of BG particles due to their amorphous structure. In the present study, EDX analysis was performed to confirm the compositional retention of BG particles in the composites. As can be seen from Fig. 3a, only Mg, Zn and a small amount of element O were detected by EDX, and the mass ratio of Mg and Zn was close to that of the designed ZK30 composition, which means that the matrix composition was well preserved after the casting procedure. As to the BG particles in the composites, EDX analysis revealed the presence of Ca, Si, Na, O and a small amount of Mg (Fig. 3b). The presence of Mg could be attributed to the magnesium surrounding the BG particles or to mild reactions at the interfaces between the matrix and BG particles. For a clearer comparison, the weight percents of Ca, Si, Na and O of the analyzed particles as determined by EDX are listed in Table 2 and compared with those of the theoretical elemental composition of BG particles. It can be seen that the discrepancies between the as-measured and theoretical composition data were not marked, suggesting the retention of BG particles in the composites. It is of particular importance to note the high Si concentration in the BG particles, which is necessary for the excellent bioactivity of a bioactive glass [18]. EPMA analysis indeed revealed the silicon element with enhanced intensities scattered all over the matrix, which corresponded to the locations of BG particles (Fig. 4). It was thus clear that the basic chemical composition of BG particles remained largely intact during semi-solid high pressure casting, which would be essential for the preservation of their bioactivity. In other words, semi-solid high pressure casting appeared to be a viable method to fabricate ZK30-BG composites. Fig. 3


Magnesium-based composites with improved in vitro surface biocompatibility.

Huan Z, Leeflang S, Zhou J, Duszczyk J - J Mater Sci Mater Med (2010)

Distribution of Si in the composite as determined by EPMA. The analysis area on a ZK30-BG MMC sample is indicated by the square in the Backscattered Electron Image (BEI). The intensity of the Si Kα in the framed area is represented by the gray scale (or a jet-like colour scheme in the online version). Here black represents a low signal and light gray-white higher intensity signals (pinkish-white the highest intensity in the online version)
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Related In: Results  -  Collection

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Fig4: Distribution of Si in the composite as determined by EPMA. The analysis area on a ZK30-BG MMC sample is indicated by the square in the Backscattered Electron Image (BEI). The intensity of the Si Kα in the framed area is represented by the gray scale (or a jet-like colour scheme in the online version). Here black represents a low signal and light gray-white higher intensity signals (pinkish-white the highest intensity in the online version)
Mentions: Since the biomedical property of a bioactive ceramic material is closely related to its chemical composition, it is of utmost importance to keep the compositional characteristics of BG particles in the composite unchanged [18]. In general, it is rather difficult to ascertain the retention of the chemical composition of BG particles due to their amorphous structure. In the present study, EDX analysis was performed to confirm the compositional retention of BG particles in the composites. As can be seen from Fig. 3a, only Mg, Zn and a small amount of element O were detected by EDX, and the mass ratio of Mg and Zn was close to that of the designed ZK30 composition, which means that the matrix composition was well preserved after the casting procedure. As to the BG particles in the composites, EDX analysis revealed the presence of Ca, Si, Na, O and a small amount of Mg (Fig. 3b). The presence of Mg could be attributed to the magnesium surrounding the BG particles or to mild reactions at the interfaces between the matrix and BG particles. For a clearer comparison, the weight percents of Ca, Si, Na and O of the analyzed particles as determined by EDX are listed in Table 2 and compared with those of the theoretical elemental composition of BG particles. It can be seen that the discrepancies between the as-measured and theoretical composition data were not marked, suggesting the retention of BG particles in the composites. It is of particular importance to note the high Si concentration in the BG particles, which is necessary for the excellent bioactivity of a bioactive glass [18]. EPMA analysis indeed revealed the silicon element with enhanced intensities scattered all over the matrix, which corresponded to the locations of BG particles (Fig. 4). It was thus clear that the basic chemical composition of BG particles remained largely intact during semi-solid high pressure casting, which would be essential for the preservation of their bioactivity. In other words, semi-solid high pressure casting appeared to be a viable method to fabricate ZK30-BG composites. Fig. 3

Bottom Line: In this study, bioactive glass (BG, 45S5) particles were added to a biodegradable magnesium alloy (ZK30) through a semi-solid high-pressure casting process in order to improve the surface biocompatibility of the biomaterial and potentially its bioactivity.SEM, EDX and EPMA showed the retention of the morphological characteristics and composition of BG particles in the as-cast composite materials.In vitro tests in a cell culture medium confirmed that the composites indeed possessed an enhanced ability to induce the deposition of a bone-like apatite layer on the surface, indicating an improved surface biocompatibility as compared with the matrix alloy.

View Article: PubMed Central - PubMed

Affiliation: Department of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, 2628 CD, Delft, The Netherlands.

ABSTRACT
In this study, bioactive glass (BG, 45S5) particles were added to a biodegradable magnesium alloy (ZK30) through a semi-solid high-pressure casting process in order to improve the surface biocompatibility of the biomaterial and potentially its bioactivity. The observation of the as-cast microstructures of ZK30-BG composites indicated homogeneous dispersion of BG particles in the matrix. SEM, EDX and EPMA showed the retention of the morphological characteristics and composition of BG particles in the as-cast composite materials. In vitro tests in a cell culture medium confirmed that the composites indeed possessed an enhanced ability to induce the deposition of a bone-like apatite layer on the surface, indicating an improved surface biocompatibility as compared with the matrix alloy.

Show MeSH
Related in: MedlinePlus