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ABSTRACT: During the past two decades, research on ceramic scaffolds for bone regeneration has progressed rapidly, however currently available porous scaffolds remain unsuitable for load bearing applications. The key to success is to apply microstructural design strategies to develop ceramic scaffolds with mechanical properties approaching those of bone. Here we report on the development of a unique microstructurally-designed ceramic scaffold, strontium-hardystonite-gahnite (Sr-HT-Gahnite) with 85% porosity, 500 μm pore size with a competitive compressive strength of 4.1±0.3MPa and compressive modulus of 170±20MPa. The in vitro biocompatibility of the scaffolds was studied using of primary human bone-derived cells.The ability of Sr-HT-Gahnite scaffolds to repair of critical-sized bone defects was also investigated in a rabbit radius under normal load with β-tricalcium phosphate/hydroxyapatite (TCP/HA) scaffolds used in the control group. Studies with primary human osteoblast cultures confirmed the bioactivity of these scaffolds, and regeneration of rabbit radial critical defects demonstrated this material induces new bone defect bridging with clear evidence of regeneration of original radial architecture and bone marrow environment.
Acta biomaterialia 03/2013; · 3.98 Impact Factor
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ABSTRACT: This is the first reported study to prepare highly porous baghdadite (Ca(3)ZrSi(2)O(9)) scaffolds with and without surface modification and investigate their ability to repair critical-sized bone defects in a rabbit radius under normal load. The modification was carried out to improve the mechanical properties of the baghdadite scaffolds (particularly to address their brittleness) by coating their surfaces with a thin layer (∼400nm) of polycaprolactone (PCL)/bioactive glass nanoparticles (nBGs). The β-tricalcium phosphate/hydroxyapatite (TCP/HA) scaffolds with and without modification were used as the control groups. All of the tested scaffolds had an open and interconnected porous structure with a porosity of ∼85% and average pore size of 500μm. The scaffolds (six per scaffold type and size of 4mm×4mm×15mm) were implanted (press-fit) into the rabbit radial segmental defects for 12weeks. Micro-computed tomography and histological evaluations were used to determine bone ingrowth, bone quality, and implant integration after 12weeks of healing. Extensive new bone formation with complete bridging of the radial defect was evident with the baghdadite scaffolds (modified/unmodified) at the periphery and in close proximity to the ceramics within the pores, in contrast to TCP/HA scaffolds (modified/unmodified), where bone tended to grow between the ulna adjacent to the implant edge. Although the modification of the baghdadite scaffolds significantly improved their mechanical properties, it did not show any significant effect on in vivo bone formation. Our findings suggest that baghdadite scaffolds with and without modification can serve as a potential material to repair critical sized bone defects.
Acta biomaterialia 07/2012; 8(11):4162-72. · 3.98 Impact Factor
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Advances in experimental medicine and biology 02/2001; 484:229-36. · 1.09 Impact Factor
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ABSTRACT: This study characterizes humoral opsonins from the tunicate, Pyura stolonifera. The predominant opsonic components in P. stolonifera hemolymph were found to be calcium-dependent lectins with broad carbohydrate specificities. The opsonic lectins were purified by carbohydrate affinity chromatography which eluted a complex pattern of proteins ranging in molecular mass from 80 to >200kDa. Reducing and two dimensional SDS-PAGE indicated that the diversity of mature lectins evident under non-reducing conditions resulted from the differential oligomerization of two polypeptide sub-units (35 and 22kDa). In addition to lectin-mediated opsonic activity, hemolymph was also found to contain proteolytically activated opsonins. These data suggest that multiple, possibly interactive opsonic systems co-exist in P. stolonifera.
Developmental & Comparative Immunology 25(5-6):377-85. · 3.27 Impact Factor
