Bioceramics and Biominerals and Their Nanostructures
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Bioceramics and Biominerals and Their Nanostructures Shulin Wen and Jingwei Feng1 HREM Analytical Center, College of Mater. Sci. and Eng., Shandong University 73 Jingshi Road, Jinan, Shandong, 250061 CHINA ABSTRACT Artificial hydroxyapatite with chemical formula of Ca10(PO4)6(OH)2 is the best as bioceramics due to its composition and structure being similar with inorganic part of hard tissues. The alloys especially with Ti, Ni and Co contents are very promising as a kind of biomaterials due to their high strength and high toughness. The alloys as biomaterials need good final surface properties by proper surface treatment. By using clinical treatment with machining, cleaning, sterilization, we obtained Ti-oxides surface with 4-6 nm in thickness which are very good in property with chemical composition of TiO2 + Ti2O3 + TiO. However, the Ti-alloy with an artificial hydroxyapatite surface is even much better than that with the surface of Ti-oxides due to its high bioactivity. Human bones and human teeth with a chemical composition of Ca10(PO4)6(OH)2 and the structure of hydroxyapatite are commonly considered as bio-mineral. In nature the pears and shells are also a kind of bio-minerals. Our observations showed that human bone is a complex material with a layered composite structure. The hydroxyapatite mineral crystals that reinforce the organic proteinceous component are about 35 nm wide, irregular, plate-like crystals reside initially in the hole zones of the collagen microfibris: later fill available space within the collagen fibrils. At present paper nanostructure features of both bioceramics and biominerals have been characterized with comparison between each other’s. INTRODUCTION Biomaterials include some ceramics, metals and polymers, which are bioactive or no reaction with tissues. Bio-ceramics are considered as man-made ceramics which are usually used at the recovery of damage in hard tissues. The common problem for a variety of above biomaterials is the research of the interface between materials and biosystem (tissues). This interface is very complicated in structure, which not only involve in atomic arrangement and molecular assembly from different phases but also involve in their multi-reaction. An adsorbed, extracellular layer consisting of water, ions, and biomolecules covers the biomaterial surface. Cells approaching the implant material surface will interact primarily with this spacer layer. Since the properties and structures of the material surface influence the exact nature of the extracellular layer, it mediates a cell-surface interaction, even if there is no direct cell -surface contact at molecular level. The investigation of interface between the biomineral [1] and tissues is very important because it could give us some clues to resolve the problem of the interface between bioceramics and tissues. The investigation of biominerals such as bones, shells and peals
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are also important, specially, for the investigation of their relationship between structure and property which may lead to imp
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