2006 Fiscal Year Final Research Report Summary
Effects of Electrical Polarization of Hydroxyapatite ceramics on Bone Conduction
| Project/Area Number |
17500302
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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 | Tokyo Medical and Dental University |
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Principal Investigator |
ITOH Soichiro Tokyo Medical and Dental University, Division of Molecular Tissue Engineering, Human Gene and Sciences Center, Associate Professor, 疾患遺伝子実験センター, 客員助教授 (10242190)
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| Co-Investigator(Kenkyū-buntansha) |
SHINOMIYA Kenichi Tokyo Medical and Dental University, Department of Orthopedic Surgery, Professor, 大学院医歯学総合研究科, 教授 (20111594)
YAMASHITA Kimihiro Institute of Biomaterials and Bioengineering, Department of Inorganic Materials, Professor, 生体材料工学研究所, 教授 (70174670)
NAKAMURA Satoshi Institute of Biomaterials and Bioengineering, Department of Inorganic Materials, Assistant Professor, 生体材料工学研究所, 助教授 (40227898)
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| Project Period (FY) |
2005 – 2006
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| Keywords | hydroxyapatite ceramics / β-tricalcium phosphate / ceramic structure / bone ingrowth / electrical polarization / osteoblast / osteoclast |
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| Research Abstract |
Experiment 1.
Large surface charges can be induced on hydroxyapatite (HAp) ceramics by proton transport polarization, but this does not affect β-tricalcium phosphate (β-TCP) because of its low polarizability. We wished to examine differences in osteogenic cell activity and new bone growth between positively or negatively surface charged HAp and HAp/TCP plates using a calvarial bone defect model. In the first group of rats, test pieces were placed with their positively charged surfaces face down on the dura mater. In a second group, test pieces were placed with their negatively charged surfaces face down on the dura mater. A third group received non-charged test pieces. Histological examination, including enzymatic staining for osteoblasts and osteoclasts, was carried out. While no bone formation was observed at the pericranium, direct bone formation on the cranial bone debris and new bone growth expanded from the margins of the sites of injury to bridge across both the positively and ne
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gatively charged surfaces of HAp and HAp/TCP plates occurred. Electrical polarization of implanted plates, including positive charge, led to enhanced osteoblast activity, though decreased osteoclast activity was seen on the positively charged plate surface. Thus, polarization of HAp ceramics may modulate new bone formation and resorption.
Experiment 2.
Hydroxyapatite ceramics are used as implants to repair damaged/removed bone, and negative or positive electrical polarization enhances osteoblast and decreases osteoclast activity, respectively, in vivo. We compared the ability of electrically polarized and non-polarized hydroxyapatite with interconnected pores (IPHA) implants to promote bone growth. Polarized or non-treated IPHAs were implanted into the right or left femoral condyle of rabbits (N=10 in each group), and we performed histological examination, including enzymatic staining for osteoblasts and osteoclasts, three and six weeks after implantation. We observed improved bone ingrowth and increased osteoblast activity in polarized implants with complete bone penetration into polarized implants occurring as early as three weeks after surgery. In contrast, non-polarized implants were not fully ossified at six weeks after surgery. Furthermore, positively charged implant regions had decreased osteoclast activity compared to negatively charged or uncharged regions. We propose two different models to explain these observations. Less
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Research Products
(17 results)
