The objective of this work was to fabricate a rigid,resorbable and osteoconductive scaffold by mimicking the hierarchical structure of the cortical bone.Aligned peptide-functionalize nanofiber microsheets were generat...The objective of this work was to fabricate a rigid,resorbable and osteoconductive scaffold by mimicking the hierarchical structure of the cortical bone.Aligned peptide-functionalize nanofiber microsheets were generated with calcium phosphate(CaP)content similar to that of the natural cortical bone.Next,the CaP-rich fibrous microsheets were wrapped around a microneedle to form a laminated microtube mimicking the structure of an osteon.Then,a set of the osteon-mimetic microtubes were assembled around a solid rod and the assembly was annealed to fuse the microtubes and form a shell.Next,an array of circular microholes were drilled on the outer surface of the shell to generate a cortical bone-like scaffold with an interconnected network of Haversian-and Volkmann-like microcanals.The CaP content,porosity and density of the bone-mimetic microsheets were 240 wt%,8%and 1.9 g/ml,respectively,which were close to that of natural cortical bone.The interconnected network of microcanals in the fused microtubes increased permeability of a model protein in the scaffold.The cortical scaffold induced osteogenesis and vasculogenesis in the absence of bone morphogenetic proteins upon seeding with human mesenchymal stem cells and endothelial colony-forming cells.The localized and timed-release of morphogenetic factors significantly increased the extent of osteogenic and vasculogenic differentiation of human mesenchymal stem cells and endothelial colony-forming cells in the cortical scaffold.The cortical bonemimetic nature of the cellular construct provided balanced rigidity,resorption rate,osteoconductivity and nutrient diffusivity to support vascularization and osteogenesis.展开更多
Octavinyl polyhedral oligomeric silsesquioxane (POSS) was polymerized on the surface of Fe3O4 nanoparticles (NPs) and then the NPs were functionalized with carboxylic acid groups using thiol-ene click reactions with t...Octavinyl polyhedral oligomeric silsesquioxane (POSS) was polymerized on the surface of Fe3O4 nanoparticles (NPs) and then the NPs were functionalized with carboxylic acid groups using thiol-ene click reactions with thioglycolic acid.The as-prepared Fe3O4@POSS-COOH magnetic hybrid NPs had mesoporous structures with an average particle diameter of 15 nm and a relatively high specific surface area of 447 m^2· g^-1.Experimental results showed that 4 mg of Fe3O4@POSS-COOH NPs efficiently adsorbed and removed methylene blue from water at 5 min.This is due to the presence of both carboxylic acid and pendant vinyl groups on the Fe3O4@POSS-COOH NPs.These NPs could be easily withdrawn from water within a few seconds under moderate magnetic field and showed high stability in acid and alkaline aqueous mediums.展开更多
基金supported by research grants to E.Jabbari from the National Science Foundation under Award Numbers CBET1403545 and IIP150024 and the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health under Award Number AR063745.
文摘The objective of this work was to fabricate a rigid,resorbable and osteoconductive scaffold by mimicking the hierarchical structure of the cortical bone.Aligned peptide-functionalize nanofiber microsheets were generated with calcium phosphate(CaP)content similar to that of the natural cortical bone.Next,the CaP-rich fibrous microsheets were wrapped around a microneedle to form a laminated microtube mimicking the structure of an osteon.Then,a set of the osteon-mimetic microtubes were assembled around a solid rod and the assembly was annealed to fuse the microtubes and form a shell.Next,an array of circular microholes were drilled on the outer surface of the shell to generate a cortical bone-like scaffold with an interconnected network of Haversian-and Volkmann-like microcanals.The CaP content,porosity and density of the bone-mimetic microsheets were 240 wt%,8%and 1.9 g/ml,respectively,which were close to that of natural cortical bone.The interconnected network of microcanals in the fused microtubes increased permeability of a model protein in the scaffold.The cortical scaffold induced osteogenesis and vasculogenesis in the absence of bone morphogenetic proteins upon seeding with human mesenchymal stem cells and endothelial colony-forming cells.The localized and timed-release of morphogenetic factors significantly increased the extent of osteogenic and vasculogenic differentiation of human mesenchymal stem cells and endothelial colony-forming cells in the cortical scaffold.The cortical bonemimetic nature of the cellular construct provided balanced rigidity,resorption rate,osteoconductivity and nutrient diffusivity to support vascularization and osteogenesis.
文摘Octavinyl polyhedral oligomeric silsesquioxane (POSS) was polymerized on the surface of Fe3O4 nanoparticles (NPs) and then the NPs were functionalized with carboxylic acid groups using thiol-ene click reactions with thioglycolic acid.The as-prepared Fe3O4@POSS-COOH magnetic hybrid NPs had mesoporous structures with an average particle diameter of 15 nm and a relatively high specific surface area of 447 m^2· g^-1.Experimental results showed that 4 mg of Fe3O4@POSS-COOH NPs efficiently adsorbed and removed methylene blue from water at 5 min.This is due to the presence of both carboxylic acid and pendant vinyl groups on the Fe3O4@POSS-COOH NPs.These NPs could be easily withdrawn from water within a few seconds under moderate magnetic field and showed high stability in acid and alkaline aqueous mediums.
