Papers by Keyword: Osteoinductivity

Abstract: Carbon/Carbon composite is considered to be one of the best biomaterials substitute to human hard tissues due to its excellent biocompatibility and the much closed elastic modulus to human skeleton. It has been widely used and studied to the fields of artificial bones materials, but the osteoinductivity need to be improved. In recent years, the commonly used surface modification to improve their bone induction, such as hydroxyapatite, chitosan and so on, which prompted the adsorption of osseous protein, adhesion and growth of cells. It is believed the surface modification and coating of the carbon/carbon composite should promote its application in artificial bones. This article reviews the modified coat of medical carbon / carbon composites in recent years, and proposed some recommendations for the development of medical carbon / carbon composite in the future.

Abstract: We previously reported functionally graded hydroxyapatite (fg-HAp) with the characteristics of blood permeability into the bulk and osteoinduction by adding low dose of bone morphogenetic protein-2 (BMP-2). In this study, we evaluated the bioactivity of the obtained dense HAp bodies in a simulated body fluid (SBF) and the osteoinductive activity with or without SBF treatment in vivo. The fg-HApSBF was prepared by immersing the fg-HAp in the SBF solution at 14 days and the surface structure was observed by SEM. The fg-HApSBF showed fine bone-like crystal on the surface of the HAp. Ectopic bone formation occurred in the fg-HAp/BMP-2 (1.0, 0.5μg) system at 3 weeks, while only in the fg-HApSBF/BMP-2 (1.0μg), bone induction was found. The histological finding showed body fluid permeation into the fg-HApSBF bulk and bone formation were obserbed.

Abstract: We developed a calcium phosphate cement that could be molded into any desired shape due to its chewing-gum-like consistency after mixing. The powder component of the cement consists of tricalcium phosphate (TCP). The liquid component consists of chitosan, citric acid and glucose solution. In this study, we used four groups of cement to investigate the mechanical properties and biocompatibility of the new biomaterial in vivo. The setting times of the cements were 5-30 min. X-ray diffraction analysis showed that the products were hydroxyapatite (HA) and dicalcium phosphate anhydrous. When the concentration of citric acid was increased, the compressive strength of specimen increased. The animal experiments showed that the material was nontoxic and osteoinductivity.

Abstract: In order to improve the bioactivity of calcium phosphate bioceramics, biphasic HA/β-TCP (BCP) bioceramics were prepared by the microwave sintering and the microwave plasma sintering. Bone-like apatite formation of the resulting samples was investigated in simulated body fluid (SBF). The samples were also implanted in dorsal muscles of healthy dogs for 1.5and 3 months. All samples after taking out were examined by histological observation. Bone formation in different sintering ways and temperatures was investigated in details. Better osteoinductivity was found in samples sintered by the microwave and microwave plasma instead of the conventional furnace, as well as by lower temperature (1050 oC) instead of higher temperature (1150 oC). It accounts for that the increase in degradability of materials sintered by microwave and microwave plasma or lower temperature leads to the better of bone-like apatite formation and bone formation due to fine grains and lower crystallinity.

Abstract: The porous structure of calcium phosphate ceramics is one of the essential conditions resulting in bone formation. The porous structure of biphasic HA/β-TCP ceramics was improved by adding microporous porosifer and the porous characteristics such as porosity, pore size and pore size distribution were determined by the mercury intrusion porosimetry, the cell culture in vitro and the animal experiment. By means of SEM and fluorescence decoration, cells were observed firstly attaching the edge of macropores of specimens and the wall of the macropores with micropores when co-cultured with HA/β-TCP ceramics. The specimens were also implanted in dorsal muscles of healthy dogs for 1.5and 3 months. More bone formation in the specimen with microporous porosifer was found by histological observation after taking out. It suggested that the micropores in the walls of macropores of bioceramics had important effect upon their osteoinduction.

Abstract: We had investigated the biocompatibility, osteoconductivity, and biodegradability of a porous composite of hydroxyapatite (HA) and poly-DL-lactide (PDLLA) implanted into rabbit femoral condyles. It showed excellent osteoconductivity and biodegradability as a bone substitute. Newly formed bones were remodeled, and materials were resorbed almost completely at 78weeks after implantation. In consideration of its biocompatibility and degradability, we investigated its potential for use as a cellular scaffold and evaluated its osteoinductive property. On implantation to the rat dorsal subcutaneous tissue loaded with syngeneic bone marrow cells, osteogenesis with enchondral ossification was seen both on and in the material at 3 weeks after implantation. This osteogenesis in the HA/PDLLA tended to get mature and newly formed bone tissues were found in the material by 6weeks. To investigate the osteoinductive property material itself has, we attempted to implant this porous composite material to extra-osseous canine dorsal muscle. At 2months, osteogenesis was seen in the pores of the material. It indicated the material induced osteogenesis with intramembranous ossification process. Therefore, HA/PDLLA might be a desirable material for bone substitutes and cellar scaffolds with osteoconductive and osteoinductive property.

Abstract: Deep-frozen morselized human bone grafts showed osteoconductivity and osteoinductivity when implanted into tibial window defects of nude rats. The osteoconductivity was assessed by measuring the total area of newly formed bone bridged by the implanted bone grafts in the entire defect area. The osteoinductivity was evidenced by the presence of active osteoblast-like cells and new bone formation around the implanted bone grafts, which were surrounded by soft tissues distant from the host cortex. Gamma irradiation at the doses of 15 or 25 kGray reduced the osteoconductivity (ANOVA and LSD tests, p<0.05) at 3 weeks post operation. The 25 kGray group had a significantly lower level of new bone formation compared with the 0 and 15 kGray groups. The evidences of osteoinductivity were only noted in the 0 and 15 kGray groups. Our data indicate that 25 kGray gamma irradiation reduces the osteoconductive and osteoinductive properties of the morselized human bone graft.

Abstract: Two sets of porous biphasic calcium phosphate ceramics (BCP) were prepared for dynamic SBF experiment: porous BCP with micropores on the walls of macropores( set A) and porous BCP with dense walls of macropores (set B). Apatite layer could only formed on the macropore walls with micropores. Four groups of specimens were prepared for animal experiments. Group A was porous BCP ceramics with micropores on the walls of macropores; group B was porous BCP with dense walls of macropores; group C was porous BCP ceramics with apatite layers formed by static SBF[2]on their surfaces; group D was porous BCP ceramics with apatite layers formed by dynamic SBF on their walls of macropores. The result of dynamic SBF animal experiments showed that microstructure of BCP played an important role in the bone-like apatite formation and osteoinductiion in biomaterials. Apatite formation may be the prerequisite of osteoinductive formation of new bone.