2005 Fiscal Year Final Research Report Summary
Antiresorptive preparation and bone grafts
| Project/Area Number |
16500310
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Biomedical engineering/Biological material science
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| Research Institution | National Institute of Advanced Industrial Science and Technology |
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Principal Investigator |
ITO Atsuo Natl Inst Adv Ind Sci Tech, Inst Human Sci Biomed Eng, Research group leader, 人間福祉医工学研究部門, 研究グループ長 (30356480)
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| Project Period (FY) |
2004 – 2005
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| Keywords | fluoride and carbonate-containing apatite / zinc-containing tricalcium phosphatephosphate / Magnesium-containing tricalcium / bone formation / osteoporosis / slow release / solubility product / ceramic artificial bone |
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| Research Abstract |
Carbonate-containing hydroxyapatite was mixed with sodium fluoride, and reacted in the temperature range of 25-800 ℃ under the carbon dioxide gas atmosphere to obtain fluoride and carbonate-containing hydroxyapatite (CFA). The synthetic conditions were optimized. A large amount of CFA with fluoride contents of 1 and 2 wt% were prepared. 300g of magnesium-containing tricalcium phosphate (MgTCP) was prepared from high purity calcium carbonate, phosphoric acid and magnesium nitrate. The CFA and MgTCP were pulverized under the strictly controlled conditions followed by mixing with zinc-containing tricalcium phosphate (ZnTCP). The CFA, MgTCP and ZnTCP powders, and their mixtures were supplied to the collaborating institutes.
MgTCP with various magnesium contents were immersed in a 0.08M acetic acid and sodium acetate buffer solution at pH5.5. The pH corresponds to the TCP/DCPD and TCP/OCP singular points. The immersion was carried out in air and nitrogen atmosphere. After equilibration, solubility product of MgTCP, Ksp=(Ca^<2+>)^<3-x>(Mg^<2+>)^x(PO^<3->_4)^2, was calculated. Solubility of MgTCP decreased with increasing Mg content. The negative logarithm of solubility product (pKsp) was regressed as pKsp=29.041+0.90467C-0.18069C^2+0.025962C^3-0.00192C^4-0.000055199C^5, where C is the Mg content of MgTCP in mol%.
Mg/Zn/F-CaP ceramic body was fabricated by pressing mixture of MgTCP, trizinc phosphate and CFA powders and by sintering in the temperature range of 700-1000℃. The Mg/Zn/F-CaP ceramic body was designed to contain 1.13%Mg, 13.6%Zn and 2.45%F. After sintering, shrinkage reached 6.88±0.92%. The sintered Mg/Zn/F-CaP was mechanically strong enough to be handled in surgical operation and can be used as a bone substitute. XRD pattern of sintered Mg/Zn/F-CaP revealed the presence of TCP and apatite phases as well as a small amount of unknown phase. Further optimization of sintering process and detailed characterization are necessary.
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