Formation of hydroxyapatite in hydrogels from tetracalcium phosphate/dicalcium phosphate mixtures.
Formation of hydroxyapatite in hydrogels from tetracalcium phosphate/dicalcium phosphate mixtures.
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由磷酸四钙/磷酸二钙混合物在水凝胶中形成羟基磷灰石。
DOI：
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发表时间：
1989
期刊：
影响因子：
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通讯作者：
M. Ohashi
中科院分区：
文献类型：
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作者：
A. Sugawara;J. Antonucci;S. Takagi;L. C. Chow;M. Ohashi
由磷酸四钙（TTCP）与磷酸二钙（DCP）的环境反应形成的磷灰质磷酸钙水泥，最近有报道。水或稀释的aq. H3PO4（0.2%）作为该反应的液体载体。本研究的目的是确定羟基磷灰石（HAp）是否可以在含有TTCP/DCP混合物的自固化水凝胶复合材料中形成。测定了水凝胶复合材料的凝固时间（ST）和直径拉伸强度（DTS）。水凝胶有两种类型：(1)乙烯基热固性凝胶，由HEMA（2-羟乙基甲基丙烯酸酯）和交联单体共聚而成；(2)由聚烯酸（如聚丙烯酸）形成的聚电解质基水凝胶。圆柱形标本长6 mm，高3 mm，在水中保存30天。通过自由基（过氧化苯甲酰/叔芳胺）引发，HEMA复合材料在7 ~ 15 min内硬化。聚电解质胶结剂在6-8 min内硬化。在37℃的水中保存不同时期后，一些标本用x射线光谱检测HAp。即使在水储存30天后，HEMA复合材料中也没有观察到HAp的形成，但在聚酸胶结物中检测到HAp的形成。HEMA复合材料的24 h DTS值（14 ~ 26 MPa）高于聚酸水泥（7 ~ 12 MPa）。因此，水含量和pH值可能是控制TTCP/DCP混合物水凝胶复合材料中HAp形成速率和程度的因素。
Apatitic calcium phosphate cements, formed by the ambient reaction of tetracalcium phosphate (TTCP) with dicalcium phosphates (DCP), have been recently reported. H2O or dilute aq. H3PO4 (0.2%) is used as the liquid vehicle for this reaction. The aim of this study was to ascertain if hydroxyapatite (HAp) can form in self-cured hydrogel composites containing TTCP/DCP mixes. The setting times (ST) and diametral tensile strengths (DTS) of these hydrogel composites were also determined. The hydrogels were of two types: (1) vinyl thermosets derived from the copolymerization of HEMA (2-hydroxyethyl methacrylate) and cross-linking monomers, and (2) polyelectrolyte-based hydrogels formed from aq. poly(alkenoic acids), e.g., poly(acrylic acid). Cylindrical specimens 6 mm D x 3 mm H were prepared and stored in H2O for up to 30 days. The HEMA composites were hardened in 7-15 min by free radical initiation (benzoyl peroxide/tertiary aromatic amine). The polyelectrolyte cements were hardened in 6-8 min. After various periods of storage in H2O at 37 degrees C, some of the specimens were examined by X-ray spectroscopy for HAp. HAp formation was not observed in the HEMA composites even after 30 days of H2O storage but was detected in the polyacid cements. The 24-h DTS values of the HEMA composites (14-26 MPa) were higher than those of the polyacid cements (7-12 MPa). Both the H2O content and pH may thus be factors controlling the rate and extent of HAp formation in hydrogel composites containing TTCP/DCP mixtures.