Zhang Yanni
,
Han Yong
,
Zhang Lan
材料科学技术（英）
doi:10.1016/j.jmst.2016.06.007
SrTiO3 nanotube films with good adhesion strengths to Ti substrates were fabricated by using a hybrid approach with a modified anodization and a hydrothermal treatment (HT). The effect of Sr2+ concentration in HT solutions on the morphologies and phase components of the nanotubes were investigated, the SrTiO3 nanotubes formation mechanism was explored, and the adhesion strengths, hydrophilicity and apatite-forming ability of the SrTiO3 nanotubes were also evaluated. The results demonstrated that with increasing the incorporation of Sr2+ into the nanotubes, no obvious changes of the lengths and outer diameters of the nanotubes were observed, but the wall thickness and the crystallinity of SrTiO3 in the nanotubes increased. The accumulation of Sr at the inner tube wall indicated that the reaction of Sr2+ with TiO2 mainly occurred in the vicinity of internal surfaces of the closely arranged nanotubes. The formation of the SrTiO3 nanotubes could be attributed to an in situ dissolution-recrystallization process. The SrTiO3 nanotubes exhibited good hydrophilicity and bioactivity, and the induced apatite preferred to nucleate on the nanotubes with higher crystallinity and Sr content, indicating a good bio-adaptability of the SrTiO3 nanotubes for orthopedic application.
关键词:
SrTiO3 nanotubes
,
Modified anodization
,
Hydrothermal treatment
,
Bio-adaptability
Wan Peng
,
Tan Lili
,
Yang Ke
材料科学技术（英）
doi:10.1016/j.jmst.2016.05.003
Magnesium (Mg) and its alloys as a novel kind of biodegradable material have attracted much fundamental research and valuable exploration to develop its clinical application. Mg alloys degrade too fast at the early stage after implantation, thus commonly leading to some problems such as osteolysis, early fast mechanical loss, hydric bubble aggregation, gap formation between the implants and the tissue. Surface modification is one of the effective methods to control the degradation property of Mg alloys to adapt to the need of organism. Some coatings with bioactive elements have been developed, especially for the micro-arc oxidation coating, which has high adhesion strength and can be added with Ca, P, and Sr elements. Chemical deposition coating including bio-mimetic deposition coating, electro-deposition coating and chemical conversion coating can provide good anticorrosion property as well as better bioactivity with higher Ca and P content in the coating. From the biodegradation study, it can be seen that surface coating protected the Mg alloys at the early stage providing the Mg alloy substrate with lower degradation rate. The biocompatibility study showed that the surface modification could provide the cell and tissue stable and weak alkaline surface micro-environment adapting to the cell adhesion and tissue growth. The surface modification also decreased the mechanical loss at the early stage adapting to the load-bearing requirement at this stage. From the interface strength between Mg alloys implants and the surrounding tissue study, it can be seen that the surface modification improved the bio-adhesion of Mg alloys with the surrounding tissue, which is believed to be contributed to the tissue adaptability of the surface modification. Therefore, the surface modification adapts the biodegradable magnesium alloys to the need of biodegradation, biocompatibility and mechanical loss property. For the different clinical application, different surface modification methods can be provided to adapt to the clinical requirements for the Mg alloy implants.
关键词:
Bio-adaptability
,
Coating
,
Biodegradable
,
Magnesium alloys
,
Orthopedic implants
