The hybrid functionally graded materials(FGM) of hydroxyapatite(HA), stainless steel 316L(SS316L) and carbon nanotubes(CNT) were synthesized for biomedical implants. Three different types of FGM were produced by the c...The hybrid functionally graded materials(FGM) of hydroxyapatite(HA), stainless steel 316L(SS316L) and carbon nanotubes(CNT) were synthesized for biomedical implants. Three different types of FGM were produced by the combination of SS316 L and CNT to reinforce HA in discrete layers of FGM. In the first type of FGM, concentration of SS316 L was varied from 10% to 40%(mass fraction) with an increment of 10% to reinforce micro HA. In the second type of FGM, 0.5%(mass fraction) functionalized CNT was added by maintaining the rest of composition as that of the first type of FGM. In the third type of FGM, mixture of micro and nano HA(mass ratio1:1) was used, keeping rest of composition similar to the second type of FGM. All types of FGM were subjected to uniaxial compaction and sintered by pressureless sintering technique at similar compaction and sintering parameters. The results show that the densification is enhanced with the addition of CNT and nanocrystalline HA in the FGM. Hardness and fracture toughness increase in both FGM reinforced with CNT, but the increase of the hardness and fracture toughness are more pronounced in FGM with micro and nanocrystalline HA.展开更多
Magnesium alloys show promise for application in orthopedic implants, owing to their biodegradability and biocompatibility. In the present study, ternary Mg-(3.5,6.5 wt%) Li-(0.2, 0.5, 1.0 wt%) Ca alloys were develope...Magnesium alloys show promise for application in orthopedic implants, owing to their biodegradability and biocompatibility. In the present study, ternary Mg-(3.5,6.5 wt%) Li-(0.2, 0.5, 1.0 wt%) Ca alloys were developed. Their mechanical strength, corrosion behavior and cytocompatibility were studied. These alloys showed improved mechanical strength than pure Mg and exhibited suitable corrosion resistance. Furthermore, Mg-3.5Li-0.5Ca alloys with the best in vitro performance were implanted intramedullary into the femurs of mice for 2 and 8 weeks. In vivo results revealed a significant increase in cortical bone thickness around the Mg-3.5Li-0.5Ca alloy rods, without causing any adverse effects.Western blotting and immunofluorescence staining of β-catenin illustrated that Mg-3.5Li-0.5Ca alloy extracts induced osteogenic differentiation of human bone marrow-derived mesenchymal stem cells(hBMMSCs) through the canonical Wnt/β-catenin pathway. Our studies demonstrate that Mg-3.5Li-0.5Ca alloys hold much promise as candidates for the facilitation of bone implant application.展开更多
基金GIK Institute for financial assistance and providing research facilitiessupported by the Basic Research program through the National Research Foundation of Korea (NRF) funded by Ministry, Science and Technology (MEST) (2011-0030058)
文摘The hybrid functionally graded materials(FGM) of hydroxyapatite(HA), stainless steel 316L(SS316L) and carbon nanotubes(CNT) were synthesized for biomedical implants. Three different types of FGM were produced by the combination of SS316 L and CNT to reinforce HA in discrete layers of FGM. In the first type of FGM, concentration of SS316 L was varied from 10% to 40%(mass fraction) with an increment of 10% to reinforce micro HA. In the second type of FGM, 0.5%(mass fraction) functionalized CNT was added by maintaining the rest of composition as that of the first type of FGM. In the third type of FGM, mixture of micro and nano HA(mass ratio1:1) was used, keeping rest of composition similar to the second type of FGM. All types of FGM were subjected to uniaxial compaction and sintered by pressureless sintering technique at similar compaction and sintering parameters. The results show that the densification is enhanced with the addition of CNT and nanocrystalline HA in the FGM. Hardness and fracture toughness increase in both FGM reinforced with CNT, but the increase of the hardness and fracture toughness are more pronounced in FGM with micro and nanocrystalline HA.
基金supported by the National Key Research and Development Program of China (2016YFC1102900 and 2016YFC1102402)the National Natural Science Foundation of China (81771039, 81470769 and 51431002)+2 种基金the Project for Culturing Leading Talents in Scientific and Technological Innovation of Beijing, China (Z171100001117169)the NSFC-RFBR Cooperation Project (51611130054)the NSFC/RGC Joint Research Scheme (51361165101 and 5161101031)
文摘Magnesium alloys show promise for application in orthopedic implants, owing to their biodegradability and biocompatibility. In the present study, ternary Mg-(3.5,6.5 wt%) Li-(0.2, 0.5, 1.0 wt%) Ca alloys were developed. Their mechanical strength, corrosion behavior and cytocompatibility were studied. These alloys showed improved mechanical strength than pure Mg and exhibited suitable corrosion resistance. Furthermore, Mg-3.5Li-0.5Ca alloys with the best in vitro performance were implanted intramedullary into the femurs of mice for 2 and 8 weeks. In vivo results revealed a significant increase in cortical bone thickness around the Mg-3.5Li-0.5Ca alloy rods, without causing any adverse effects.Western blotting and immunofluorescence staining of β-catenin illustrated that Mg-3.5Li-0.5Ca alloy extracts induced osteogenic differentiation of human bone marrow-derived mesenchymal stem cells(hBMMSCs) through the canonical Wnt/β-catenin pathway. Our studies demonstrate that Mg-3.5Li-0.5Ca alloys hold much promise as candidates for the facilitation of bone implant application.
