Papers by Keyword: Carbonate Apatite

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Authors: E. Barros, J. Alvarenga, Gutemberg Alves, B. Canabarro, G.V.O. Fernandes, Antonella M. Rossi, J.M. Granjeiro, M. Calasans-Maia
Abstract: The objective of this study was to investigate the in vitro and in vivo biological responses to carbonate apatite (cHA) in comparison to hydroxyapatite (HA). Spheres (400<ø>500 μm) of both materials were synthesized under 5°C (cHA) and 90°C (HA) and not sintered. The in vitro cytocompatibility was determined by the XTT assay, according to ISO 10993-5:2009, after exposure of MC3T3-E1 cells to the materials extracts. Ethics Commission on Teaching and Research in Animals approved this project (CEPA/NAL 193/10) and, subsequently, the biomaterials were grafted in the subcutaneous tissues of mice (n=15). After 1 and 3 weeks, five animals of each group were killed for samples removal containing biomaterials and surrounding tissues for histological examination. Semi-serial (5-μm thick) sections were cut and stained with Hematoxylin and Eosin (HE) and the presence of inflammatory infiltrates and biomaterials resorption were evaluated. The experimental group of 3 weeks didn’t show the presence of spheres of both biomaterials and few spheres were observed after 1 week. Histological analysis showed the granulation tissue around the biomaterials with the presence of multinucleated giant cells. After 3 weeks it was observed the presence of fibrous tissue around biomaterials and few inflammatory cells. No signals of tissue necrosis were observed in both groups in all experimental studied periods. Nanostructured carbonate apatite spheres are cytocompatible, biocompatible and present initial biosorption on the subcutaneous comparable to stoichiometric HA, indicating its suitability for further studies on regenerative medicine.
Authors: Simone Sprio, Gian Carlo Celotti, Elena Landi, Anna Tampieri
Abstract: A series of synthetic apatites bulk samples, characterized by different atomic substitutions were polarized by field of 1 and 2 kV·cm-1 at 300 °C. The thermally stimulated depolarization currents (TSDC) were measured and the stored electric charge density evaluated. The recent development in the synthesis of non-stoichiometric HA powders, whose chemical composition resembles that of the natural bone, is promising for the realization of improved biomimetic implants for bone substitution; therefore, electrical polarization applied on the ceramic pieces could further enhance the already strong bioactivity of these materials. The depolarization processes in the various material were evaluated by the Arrhenius’ method and related with the corresponding chemical features; finally, SEM observations of some polarized samples immersed in SBF at 37 °C revealed a wide growth of HA particles within a few days in all the investigated materials.
Authors: Racquel Z. LeGeros, Dindo Q. Mijares, J. Park, X.-F. Chang, I. Khairoun, Regina Kijkowska, Renata Dias, John P. LeGeros
Abstract: Our earlier studies showed that several ions inhibit the crystal growth of apatite and promote the formation of amorphous calcium phosphates (ACP). These ions include: magnesium (Mg), zinc (Zn), stannous (Sn), ferrous (Fe), carbonate (CO3), pyrophosphate (P2O7). The purpose of this study was to investigate the effect of combination of these ions (e.g., Mg & CO3, Mg & P2O7, Mg & Zn, etc) on the formation and stability of ACP. ACP compounds containing the different ions were prepared at 25 and 37oC according to the method we previously described. Chemical stability was investigated by suspending the different ACP preparations in solutions with or without inhibitory ions. Thermal stability was determined by sintering the ACP at different temperatures. Dissolution properties were determined in acidic buffer. The ACP before and after chemical or thermal treatment were analyzed using X-ray diffraction, infrared spectroscopy, and thermogravimetry. Results showed synergistic effects of inhibitory ions on the formation of ACP. ACP materials, regardless of their composition, remained amorphous even after heat treatment at 400oC. Transformation of ACP to other calcium phosphate phases depended on the pH and on the solution composition.
Authors: Y. Miyamoto, T. Toh, Tetsuya Yuasa, M. Takechi, Y. Momota, M. Nagayama, Ishikawa Kunio, Kiyoshi Suzuki
Authors: Myrna Nurlatifah Zakaria, Arief Cahyanto, Ahmed El-Ghannam
Abstract: Silica-calcium phosphate composite (SCPC) and carbonate apatite (CO3Ap) are resorbable bioactive materials with the ability to adapt to bone structure and to induce bone regeneration. Considering the similarity between bone and dental structure, where both are mainly composed of calcium deficient carbonate containing hydroxyapatite, we hypothesize that a SCPC-CO3Ap bone cement might also be favorable for the regeneration of dentin and pulp tissue. Therefore, in the present study we report on the effect of composition and structure of SCPC-CO3Ap cement on the morphology, setting and mechanical properties of the material. The novel bioceramics cement composed of vaterite, dicalcium phosphate anhydrous (DCPA) and SCPC. The powder cement ratio divided into 5 groups: group 1 (60% DCPA : 40% vaterite : 0% SCPC) as a control, group 2 (60% DCPA : 10% vaterite : 30% SCPC), group 3 (60% DCPA : 20% vaterite : 20% SCPC), group 4 (60% DCPA : 30% vaterite : 10% SCPC), and group 5 (60% DCPA : 0% vaterite : 40% SCPC). Each group was mixed by 1M Na2HPO4 aqueous solution at liquid to powder ratio of 0.5 and hardened at 37°C and 100 % of relative humidity for 72 hours. Set cement was examined by X-Ray diffraction (XRD), scanning electron microscopy (SEM) and the mechanical strength was evaluated by diametral tensile strength. XRD patterns revealed that the apatite formation was formed after 72 hours, however the intensity of apatite varied based on the SCPC content. The DTS evaluation indicated that group 3 has the highest mechanical strength compared to others. This was supported by SEM analysis of set cement showing more compact surface microstructure of group 2 and 3 compared to other different ratio and control group. The novel bioceramics cement was successfully made using vaterite, DCPA and SCPC. This new cement is currently being investigated for dental application to induce dentinogenesis.
Authors: Thi Bang Le, Xing Ling Shi, Ishikawa Kunio, Radzali Othman
Abstract: The aim of this research work was to investigate in vitro effect of the carbonate apatite/poly (ε-caprolactone) (CO3Ap/PCL) on α-tricalcium phosphate (α-TCP) foam was produced by sintering CaCO3 and CaHPO42H2O at 1500°C for 5 h. It was then coated with carbonate apatite (CO3Ap)/Poly-ε-caprolactone (PCL) (wt/wt=1/3) to improve both mechanical and biological properties. The initial cell attachment and proliferation of the bone marrow cells were carried out on the α-TCP and CO3Ap/PCL-coated α-TCP foams. The cell proliferation was calculated by AlamarBlue assay. The cells were able to migrate and proliferate well on both α-TCP and CO3Ap/PCL-coated α-TCP foams indicating an excellent biocompatibility. The incorporation of CO3Ap on the coating layer improved cellular attachment and accelerated proliferation. Thus, CO3Ap/PCL-coated α-TCP foam might be a promising candidate as implant material.
Authors: A.H.K. Chou, Racquel Z. LeGeros, Dindo Q. Mijares, C. Frondoza, John P. LeGeros
Abstract: The osteoconductive property of calcium phosphate (CaP) biomaterials allow attachment, proliferation, migration, and phenotypic expression of bone cells leading to formation of new bone. The purpose of research is to develop new method of mineralizing commercial GBR membranes with calcium phosphate (CaP) and determine cell response. Resolut Adapt LT (Gore-tex) composed of co-polymer PGA/TMC and Biomend Extend (Zimmer) composed of bovine collagen were used. Membranes were mineralized with CaP using precipitation and new microwave methods. The mineralized and non-mineralized membranes were characterized using SEM, EDS, XRD, FT-IR, and TGA. Cell response to mineralized and non-mineralized membranes was determined using human osteoblastlike cells (MG-63). Microwave method was more efficient in terms of amount of minerals incorporated with membranes and time required. SEM, EDS, and FT-IR identified carbonate apatite in the mineralized membranes. No significant difference in cell proliferation was observed between mineralized and non-mineralized membranes. Greater production of type 1 collagen was observed with CaP mineralized membranes.
Authors: Ishikawa Kunio
Abstract: Inorganic component of bone is not hydroxyapatite but carbonate apatite. Although pure carbonate apatite (CO3Ap) has not been prepared due to the limited thermal stability of CO3Ap, dissolution - precipitation method using precursor block allows fabrication of pure CO3Ap. Fabrication of CO3Ap, cell response, tissue response and improvement of CO3Ap will be discussed.
Authors: Miho Nakamura, Teuvo Hentunen, Jukka Vääräniemi, Jukka Salonen, Naoko Hori, Kimihiro Yamashita
Abstract: @font-face { font-family: "MS 明朝"; }@font-face { font-family: "Cambria Math"; }@font-face { font-family: "@MS 明朝"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0mm 0mm 0.0001pt; font-size: 10pt; font-family: "Times New Roman"; }.MsoChpDefault { font-size: 10pt; }div.WordSection1 { page: WordSection1; } Bioresorbable materials may be advantageous for use in bone regeneration applications because they do not leave residues of foreign material, improving the long-term success of implant restoration. The purpose of this study was to investigate the osteoclastogenesis and bioresorption of synthesized calcium phosphate ceramic materials for orthopaedic and dental biomaterial applications. Differentiation into mature human osteoclasts on carbonated hydroxyapatite (CA) was significantly enhanced compared to hydroxyapatite (HA). Osteoclasts derived from human peripheral mononuclear blood cells adhered and differentiated into giant multinuclear TRAP- positive cells on every type of synthesized sample based on the histological analysis. Morphological observations using fluorescence and quantitative analysis revealed that the actin rings of osteoclasts on CA were thick and small in diameter, similar to the rings found on bone slices. Scanning electron microscopic images and quantitative analysis indicated that the resorption pits on CA were significantly deeper than those on HA due to the enhanced tight sealing ability between osteoclasts and their substrate.
Authors: Natalie Ohashi, Miho Nakamura, Akiko Nagai, Yumi Tanaka, Yasutaka Sekijima, Kimihiro Yamashita
Abstract: Various bioactive calcium phosphates such as hydroxyapatite (HA) and carbonate apatite (CA) bone substitutes have been studied because of the biocompatibility and osteoconductivity when implanted into bone defects. In this study, the interaction between bioceramics and osteoclast-like cell using the cell-line such a RAW264 was examined for the investigation of the important factors of the osteoclastic responses. From the results, the possibility of effectiveness by surface geometry and chemical property means solubility was suggested. Moreover, it was considerable that the CA induced much stronger responses to osteoclast-like cells than the HA.
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