Synthesis of silicon-substituted hydroxyapatite by a hydrothermal method with two different phosphorous sources

Silicon-substituted hydroxyapatite (Si-HA) with up to 1.8 wt% Si content was prepared successfully by a hydrothermal method, using Ca(NO₃)₂, (NH₄)₃PO₄ or (NH₄)₂HPO₄ and Si(OCH₂CH₃)₄ (TEOS) as starting materials. Silicon has been incorporated in hydroxyapatite (HA) lattice by partially replacing phosphate (PO₄³⁻) groups with silicate (SiO₄⁴⁻) groups resulting in Si-HA described as Ca₁₀(PO₄)_6−x(SiO₄)_x(OH)_2−x. X-ray diffraction (XRD), Fourier transform IR spectroscopy (FTIR), inductively coupled plasma AES (ICP-AES) and scanning electron microscopy (SEM) techniques reveal that the substitution of phosphate groups by silicate groups causes some OH⁻ loss to maintain the charge balance and changes the lattice parameters of HA. The crystal shape of Si-HA has not altered compared to silicon-free reference hydroxyapatite but Si-incorporation reduces the size of Si-HA crystallites. Based on in vitro tests, soaking the specimens in simulated body fluid (SBF), and MTT assays by human osteoblast-like cells, Si-substituted hydroxyapatite is more bioactive than pure hydroxyapatite.     

纳米羟基磷灰石颗粒固定化漆酶的研究木

利用羟基磷灰石对漆酶进行了固定化研究,确定了羟基磷灰石对漆酶固定的最适条件,并研究了不同温度下游离漆酶与固定化漆酶活力的差异,同时也对游离漆酶与固定化漆酶的Km值进行了研究.结果表明:0.08 g羟基磷灰石固定1 mL粗酶液,当固定化过程pH为6,交联剂戊二醛浓度为6%,固定化时间为1 h时,酶活力达到最大.当温度在3...     

Preparation of hydroxyapatite/poly(vinyl alcohol) composite film with uniformly dispersed hydroxyapatite particles using citric acid

Biocompatible hydroxyapatite (HA)/poly(vinyl alcohol) (PVA) composites and their transparent films were prepared by the coprecipitation and solvent casting method. The formation of HA in PVA composite powder was confirmed by the characteristic phosphate bands at 1100–1032 and 565 cm^?1 at FT‐IR spectra, and the weight ratio of HA to PVA was 50/50 examined by TGA. The crystal melting temperature of HA/PVA decreased compared with that of pure PVA. HA/PVA (50/50) composite powder and pure PVA were dissolved in dimethyl sulfoxide to obtain a film with HA/PVA weight ratio of 10/90. To improve HA particles' dispersity, which is one of the major factors affecting the mechanical properties of composite materials, various contents of citric acid were used for the preparation of HA/PVA films. At a citric acid concentration of 5 wt %, HA/PVA film with good dispersity of HA particles was obtained. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

氧化石墨烯/羟基磷灰石涂层对镁合金耐腐蚀性的影响

采用仿生法在改性模拟体液中于镁合金表面制备了羟基磷灰石(HA)涂层和氧化石墨烯/羟基磷灰石(GO/HA)复合涂层。利用扫描电子显微镜(SEM)和X射线衍射(XRD)对两种涂层进行了形貌和结构表征,通过析氢量测量、极化曲线和交流阻抗等方法分别研究了裸镁合金、含HA涂层及GO/HA涂层镁合金在pH为7.4的模拟体液(SBF)和3.5%NaCl溶液中的腐蚀行为。结果表明,氧化石墨烯增加了羟基磷灰石涂层的致密性,含GO/HA复合涂层的AZ91镁合金耐腐蚀性能最好,相对于裸镁合金,其腐蚀电流密度降低了一个数量级,析氢量降低了52%。     

在钛基上电泳沉积羟基磷灰石生物陶瓷涂层的研究

将羟基磷灰石(HAP)电泳沉积在钛基材上，得到了结构稳定的HAP生物陶瓷涂层。研究了电场强度、悬浮液温度、电泳时间、分散介质及HAP浓度对涂层形貌的影响。通过红外光谱仪(FTIR)和X射线衍射仪(XRD)对涂层的组成及结构进行了分析，并采用扫描电镜(SEM)对涂层煅烧前后的微观形貌进行了观察。结果表明：在正丁醇作为分散剂、悬浮液温度30℃、电场强度250V／cm、电泳时间300s以及HAP浓度5．0g／L的条件下可制得形貌较好的HAP生物陶瓷涂层；经二次电泳沉积及煅烧后得到的HAP生物陶瓷涂层均匀致密．     

干燥方法对化学沉淀法合成HA粉体团聚的影响

化学沉淀法合成羟基磷灰石粉体工艺简单,成本低廉,但这种方法得到的羟基磷灰石粉体极易团聚,限制了羟基磷灰石的广泛使用.本文研究了在羟基磷灰石粉体的合成过程中不同干燥方法对粉体团聚的影响.结果表明:在烘箱干燥得到的粉体团聚较严重,微波干燥使粉体的团聚程度有所减轻,冷冻干燥可有效地减弱粉体的团聚,所得到的粉体比表面积较高.同时,本文还讨论了粉体在干燥过程中团聚形成的机理.     

层状溶致液晶中纳米羟基磷灰石的合成

在一定的pH值条件下,将Ca(NO3)2和(NH4)2HPO4分别溶于C34H62O11(聚乙二醇辛基苯基醚)/C8H17OH/H2O体系层状溶致液晶溶剂层中,混合并经陈化即可在溶剂层中生成具有一定微观形貌的羟基磷灰石纳米粒子(HA),其直径可以达到10 nm,长度在100 nm以下.产物在不同温度下焙烧,分别用FTIR,XRD和TEM等对产物的结构及形貌进行分析表征.对不同反应物浓度条件下所得HA的微观形貌进行分析对比,并提出了改善团聚的有效措施.     

WE43镁合金表面电沉积羟基磷酸钙膜层在模拟体液中的耐腐蚀性

用电沉积方法在WFA3镁合金上制备了羟基磷酸钙(简称HA)膜层,发现这样制备的HA膜层具备双层结构.XRD分析表明,预沉积层的主要成分为磷酸氢钙和羟基磷酸钙,经过热浸处理后最终膜层的主要成分为羟基磷酸钙和氢氧化钙.微观形貌研究表明,磷酸氢钙为片状,羟基磷酸钙为梭形.在类似人体血浆的模拟体液(simulatedbody ...     

镁基羟基磷灰石涂层生物复合材料的研究现状

镁基羟基磷灰石涂层生物复合材料兼备了金属材料优良的力学性能和生物陶瓷材料的生物相容性,在生物医用材料领域具有广阔的应用前景。本文综述了镁及镁合金、羟基磷灰石作为医用植入材料的特点及研究现状,并简要介绍了镁基羟基磷灰石涂层生物复合材料的制备技术及方法。     

微束等离子喷涂制备羟基磷灰石涂层

采用微束等离子喷涂系统制备羟基磷灰石涂层,通过扫描电子显微分析(SEM)和X射线衍射分析(XRD)对涂层形貌、相组成和结晶度进行了研究.结果表明,随着喷涂电流和离子气流量的增加,羟基磷灰石粒子的熔化和撞击后的铺展更充分,在70～130 mm范围内随着喷涂距离的增加粒子熔化程度增加.适当的喷涂工艺条件下微束等离子喷涂制备羟基磷灰石涂层的结晶度可以相当或高于传统大气等离子喷涂制备的涂层,有利于涂层在体液环境中稳定性的提高.