羟基磷灰石的微波烧结

对羟基磷灰石的微波烧结进行了系统研究,确定了制备致密HAP生物陶瓷材料的最佳微波烧结工艺条件.通过XRD、SEM等手段研究了烧结温度和时间对HAP生物陶瓷的物相和显微结构的影响,测试了烧结收缩率和抗折强度.结果表明,微波烧结利于HAP陶瓷坯体的致密化,可以实现低温快速烧结,并提高陶瓷的机械强度;微波烧结对HAP的分解有促进作用,而且随着烧结温度升高和时间延长HAP分解程度增大.1 200℃烧结30 min的HAP陶瓷样品抗折强度最高,为(95.42±3.45)MPa,其主晶相为HAP和β-TCP.     

模拟体液法制备纳米级羟基磷灰石

以制备羟基磷灰石粉体的其中一种反应体系为研究对象,用模拟体液法制备纳米羟基磷灰石粉体。在此实验过程中,研究了反应温度、反应浓度和反应时间对羟基磷灰石粉体合成的影响。结果发现,制备纳米级羟基磷灰石的最佳工艺条件为:反应温度为60℃,浓度为15SBF,反应时间为10h。在此工艺条件下,制备的羟基磷灰石粉体的微观形貌为球形颗粒,平均颗粒直径为30nm。     

丝素蛋白/羟基磷灰石复合材料的制备及性能表征

为了改善羟基磷灰石( HAP) 的脆性和新骨诱导性, 采用共沉淀法合成HAP , 盐溶法制备丝素蛋白(SF) , 在胶体状态下将HAP 和SF 复合得到了SF/ HAP 复合材料。采用扫描电镜(SEM) 、X 射线衍射(XRD) ,傅立叶红外光谱( FIR) 对复合材料结构和化学组成进行了分析, 在模拟体液中检验了复合材料的生物活性, 并对其抗压强度进行了测定。结果表明: HAP 与SF 在纳米尺度进行了复合, 复合材料中SF 主要以β-折叠构象存在,酰胺Ⅴ红外特征峰消失,β-折叠构象的其他峰发生了移动, 表明HAP 与SF 间存在化学结合; 模拟体液中浸泡18 天后, 复合材料表面形成了片层状的HAP ; 与纯的HAP 晶体比较, 复合材料结构稳定, 具有较好生物活性和骨诱导性, 其抗压强度可达63 MPa , 可望成为理想的骨组织替换和工程支架材料。      

Synergistic Effect of Toceranib and Nanohydroxyapatite as a Drug Delivery Platform—Physicochemical Properties and In Vitro Studies on Mastocytoma Cells

A new combination of Toceranib (Toc; 5-[(5Z)-(5-Fluoro-2-oxo-1,2-dihydro-3H-indol-3-ylidene)methyl]-2,4-dimethyl-N-[2-(pyrrolidin-1-yl)ethyl]-1H-pyrrole-3-carboxamide) with nanohydroxyapatite (nHAp) was proposed as an antineoplastic drug delivery system. Its physicochemical properties were determined as crystallinity, grain size, morphology, zeta potential and hydrodynamic diameter as well as Toceranib release. The crystalline nanorods of nHAp were synthesised by the co-precipitation method, while the amorphous Toceranib was obtained by its conversion from the crystalline form during nHAp–Toc preparation. The surface interaction between both compounds was confirmed using Fourier-transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV–Vis) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS). The nHAp–Toc showed a slower and prolonged release of Toceranib. The release behaviour was affected by hydrodynamic size, surface interaction and the medium used (pH). The effectiveness of the proposed platform was tested by comparing the cytotoxicity of the drug combined with nHAp against the drug itself. The compounds were tested on NI-1 mastocytoma cells using the Alamar blue colorimetric technique. The obtained results suggest that the proposed platform shows high efficiency (the calculated IC50 is 4.29 nM), while maintaining the specificity of the drug alone. Performed analyses confirmed that nanohydroxyapatite is a prospective drug carrier and, when Toceranib-loaded, may be an idea worth developing with further research into therapeutic application in the treatment of canine mast cell tumour.     

等离子喷涂羟基磷灰石涂层的化学不均匀性和浸泡行为

利用X射线衍射仪（XRD）、电子探针（EPMA）等检测手段,对纯钛表面等离子喷涂羟基磷灰石（HA）涂层的化学不均匀性和浸泡行为以及热处理对涂层化学不均匀性的影响进行了研究.结果表明,喷涂后的涂层中存在化学不均匀性,原始颗粒越小不均匀性越严重;去离子水浸泡后,涂层表面析出Ca2P2O7等化合物,浸泡时间越长、原始颗粒越小的涂层析出物越多;热处理能使非晶相和分解相重新生成HA,提高涂层结晶度而消除非均匀现象.     

初始碳酸根含量和热处理对碳酸羟基磷灰石制备和性能的影响

以湿化学法制备了不同碳酸根含量的碳酸羟基磷灰石(carbonated hydroxyapatite,CHA).研究了热处理温度和气氛对这些CHA的烧结、热稳定性和碳酸根替代的影响.通过X射线衍射、Fourier变换红外光谱及热分析等多种测试手段表征了CHA粉体的特性.结果表明:CHA坯体的烧结温度和粉体的热稳定性与初始的碳酸根含量有关,含量越高,烧结温度越低,热稳定性越差.热处理过程中,CHA中碳酸根的替代量随热处理温度的升高而减少,并在热处理过程中A位的碳酸根较B位的碳酸根在更低的温度下失去.湿二氧化碳气氛能促进CHA的烧结,减少碳酸根的损失,提高热稳定性,有利于生成以B型替代为主的CHA.     

化学分析法精确测定羟基磷灰石中的Ca和P含量

分别采用改进的EDTA络合滴定法和高锰酸钾氧化返滴法精确测定了羟基磷灰石(HA)等物质中的钙含量,通过对比实验、精密度实验和加标回收实验对基准碳酸钙、分析纯磷酸三钙、分析纯磷酸氢钙及合成的羟基磷灰石中的钙含量进行了测定,对结果的标准偏差、相对标准偏差及回收率做了比较分析和讨论.结果表明,两种方法测定结果相当吻合,改进的EDTA法比高锰酸钾法更快速、简便,能够满足钙磷酸盐中钙含量的准确测定.钙含量测定的最大标准偏差和相对标准偏差分别为0.057和0.15 %.同时,采用磷钼酸喹啉容量法测定了样品中的磷含量.     

含硅羟基磷灰石粉体的合成及其与蛋白质的相互作用研究

将硅掺入羟基磷灰石(HA)晶格中能有效地提高HA的生物相容性.采用湿法合成了含硅羟基磷灰石微粉(Si-HA),用X射线荧光光谱(XRF)、X射线衍射(XRD)、红外光谱(FTIR)、扫描电镜(TEM)和荧光光谱等对Si-HA的晶相、结构、化学组成、形貌及其与牛血清白蛋白(BSA)的相互作用进行了表征和分析.结果表明:Si元素溶入磷灰石晶格中,使HA晶胞参数和结构发生变化,随着Si含量的增加,HA中-OH和PO3-4的吸收峰呈减弱趋势,表明SiO4-4可能部分取代了PO3-4.Si-HA与BSA作用后的PO3-4吸收峰发生变化,在Si-HA图谱中出现了蛋白质的酰胺Ⅰ带和酰胺Ⅱ带吸收峰,随着Si-HA与BSA作用时间由2h～3d的变化,BSA溶液酰胺I带位置出现蓝移,半峰宽减小且峰型变得尖锐,酰胺II带则向低频区移动.Si-HA与BSA作用3d后,开始在1139处出现PO3-4的吸收峰.荧光光谱显示:加入相同质量的HA和Si-HA后蛋白质内源荧光强度较纯BSA溶液下降,随着Si-HA中Si质量分数的增加BSA荧光强度下降幅度增大,发射峰也出现红移,且Si-HA与BSA作用较纯HA与BSA的作用强,说明Si-HA使蛋白质二级结构发生改变,Si-HA中的Ca、PO3-4、SiO4-4与BSA之间发生了相互溶解、吸附和键合等作用,证明了Si-HA与生命物质蛋白质之间具有较高的反应性能,对Si-HA的生物活性及其与BSA相互作用的机理进行了详尽的阐述.     

Near-Net-Shaped Calcium Hydroxyapatite by the Oxidation of Machinable, Calcium-Bearing Precursors (the Volume Identical Metal Oxidation, or VIMOX, Process)

A novel VIMOX (volume identical metal oxidation) route to near-net-shaped calcium hydroxyapatite, Ca₁₀(PO₄)₆(OH)₂, is demonstrated: the oxidation of machinable Ca—Ca₂P₂O₇ precursors. Mechanically alloyed mixtures of Ca and β-Ca₂P₂O₇ were compacted into disk- and bar-shaped preforms. The latter preforms could be machined into cylinders using a metalworking lathe (200 rpm, hardened steel tooling). After oxidation at 600°C in O₂, and then postoxidation annealing in H₂O/O₂ mixtures at 850°C and 1150°C, phase-pure hydroxyapatite was obtained. Because of offsetting volume changes from calcium oxidation and hydroxyapatite formation, porous hydroxyapatite bodies were produced that retained the shapes and dimensions (within 1%) of the machined precursors.     

In vivo biocompatibility and bioactivity of in situ synthesized hydroxyapatite/polyetheretherketone composite materials

Hydroxyapatite/polyetheretherketone (HA/PEEK) composite materials were prepared via an in situ synthesis process in order to achieve strong bonding between PEEK matrix and hydroxyapatite fillers, and ultimately to improve the mechanical properties of the composites. In the study, the biocompatibility of the synthesized HA/PEEK materials was investigated by acute toxicity test, hemolytic test, sensitization test, pyrogen test, intradermal test, and toxicity assay test on animal tissue and cells for the purpose of examining the possible adverse effects of the residue organic chemicals from the in situ synthesis process. In vivo bioactivity of both lab‐synthesized PEEK and HA/PEEK composites with various HA content was also studied. It is found that the in situ synthesized composite materials possess good biocompability without toxicity. Although the bioactivity of the material increases with HA content, the composite material with 5.6 vol % HA exhibits satisfactory bioactivity without compromising its excellent mechanical performance, which hints to a potential use as load‐bearing orthopedic material. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013