纳米羟基磷灰石球状晶体的合成及其吸附特性的研究

以硝酸钙和磷酸氢二铵为先驱体，通过简易的湿法合成制备了纳米级的羟基磷灰石球状晶体(简称HAP)。在适当的条件下，得到了粒径为20nm左右的球状HAP超细粉体。运用XRD和TEM对HAP结晶的形貌及结构进行分析，同时还运用Zeta电位仪研究了纳米羟基磷灰石表面电位随溶液PO4^3-浓度、Ca^2 浓度、离子强度和pH值的变化规律，并且简要地分析了纳米HAP晶体的形貌和尺寸大小与表面静电位的关系。     

水热体系中不同的前驱物对羟基磷灰石微结构的影响

纳米羟基磷灰石由于具有良好的生物相容性和生物活性而应用广泛,形貌控制对其应用至关重要。本文以磷酸为磷源前驱物,利用XRD、SEM及EDS系统比较研究了水热体系中不同钙源前驱物对合成羟基磷灰石(HAP)晶体微结构及晶体生长的影响,同时利用配位体理论对其生长机理进行了初步探讨。研究结果表明,不同钙源前驱物在pH值=10,水热温度200℃、水热时间8h的条件下,均可以合成结晶度较好的纳米羟基磷灰石晶体,不同钙源前驱物对合成HAP产物的物相、分散性、结晶性及微结构有一定的影响,碳酸钙、氢氧化钙为钙源前驱物制备的HAP为类球状的纳米HAP,氯化钙、硝酸钙为钙源前驱物制备的HAP呈短棒状,但与以硝酸钙为钙源前驱物制备的HAP晶体的结晶度、规整度、均一性及晶体极性生长特性相比,氯化钙较差。EDS分析证实,不同的前驱物合成产物的HAP晶体不含有任何杂质,但HAP晶体的钙磷比略有差别,平均钙磷比约为1.75,合成的HAP属于富钙型的纳米羟基磷灰石。     

水热法合成羟基磷灰石晶须的工艺研究

纳米羟基磷灰石（HAP）增强聚合物基复合材料是替换硬组织的最理想材料，是植入材料的研究重点之一。为了制备与天然骨结构非常相似的复合材料，必须首先制备出性能优良的的纳米HAP粉体。对水热法制备HAP纳米晶须的工艺进行了研究，研究了反应时间、温度、起始反应物的浓度、钙磷比以及反应体系的pH值对合成HAP纳米晶须形貌的影响。用X射线衍射（XRD）、扫描电镜（SEM）和红外光谱（FT-IR）法，对制备的羟基磷灰石进行了表征和分析。结果表明：生成的HAP晶须的长度及长径比随反应时间的延长而增大。温度〈150℃时，得到HAP晶须；温度〉180℃，则得到细小HAP晶体的聚集产物。当反应物的pH=9时，得到的是缺钙型的HAP；当反应物的pH〈4时，产物中出现新相磷酸氢钙；当pH=2时，得到纯的磷酸氢钙。     

抗菌羟基磷灰石的一步合成及其表征

采用共沉淀法制备羟基磷灰石(HAP),将硝酸银均匀加入反应体系中,通过温度、酸度和搅拌状态控制实现一步合成载银羟基磷灰石(Ag/HAP),该法操作简单,载银均匀,载银量易于控制,克服离子交换法和机械混合法载银的不足,其载银机理包括共沉淀和离子交换载银。所得Ag/HAP经750℃高温处理,未见分解,其结晶度提高,用最小抑菌浓度法(MIC)测得Ag/HAP对大肠杆菌和金黄色葡萄球菌有良好的抑菌性,其最小抑菌浓度为7.385×10-5。     

聚乙烯醇模板中原位水热法羟基磷灰石纳米颗粒的控制制备及表征

具有生物活性和生物相容性的羟基磷灰石/高分子复合材料的合成和可控制备,是当今生物材料领域研究的重要热点,在生物可降解聚乙烯醇高分子模板中,采用原位水热法,系统研究了具有生物活性的纳米HAP的可控制备,并对水热时间和模板剂浓度对羟基磷灰石/聚乙烯醇复合材料中HAP微粒形貌、大小的影响进行系统研究.结果表明,水熟时间从0h增加到16h,PVA/HAP微粒中HAP形貌逐渐由不规整的球状、短棒状变为规整的长棒状,水热时间从16h增加到72h,长棒状的PVA/HAP微粒的形貌变化不大;模板高分子(聚乙烯醇)浓度越大,获得的HAP微粒越小.     

仿生有序结构羟基磷灰石研究进展

羟基磷灰石(hydroxyapatite,HAP)与人体硬组织主要无机组分具有相同的化学组成,因而被认为具备良好的生物相容性、可降解性和生物活性,并已在生物医学领域得到广泛应用。迄今为止,形态丰富的HAP纳米材料及其合成方法已经被报道出来,但是具有仿生有序结构的HAP材料及其制备方法仍然是相关领域最具挑战性的方向。在包括牙釉质、皮质骨和松质骨在内的硬组织中,纳米尺度的HAP通常会按照人体受力分布情况呈可控有序结构排列。因此,通过仿生天然硬组织微结构实现HAP的可控有序组装,有望进一步提升传统HAP基生物材料的力学和生物学性能。近年来,包括氧化铝模板法、有机溶剂/小分子调控法、磷酸氢钙相转化法、高分子/蛋白分子诱导矿化法、冷冻铸造等在内的HAP有序结构制备方法已经被发展出来,并实现了在纳米、微米等尺度上有序结构的制备。最近,作者课题组报道了HAP纳米线的扩大化溶剂热制备方法,并进一步提出了适用于控制HAP纳米线有序排列的表面小分子介导的液相自组装策略,获得了尺寸和方向均可控的宏观尺度HAP纳米线仿生有序结构。相比于传统无序结构HAP基生物材料,具有仿生有序结构的HAP表现出了良好的力学和生物学性能,对新型无机生物材料的设计、制备及其生物医学应用研究具有重要的指导意义。综述了仿生有序结构HAP的研究进展,包括其结构组成、合成方法及调控机制,最后总结了仿生有序结构HAP研究领域当前面临的挑战以及未来的发展前景。     

生物羟基磷灰石的合成

综述了生物羟基磷灰石合成研究的最新进展，重点介绍和评述了羟基磷灰石的合成与制备方法，讨论了各种方法的特点和应用前景。最新的研究动态表明，羟基磷灰石研究从基本的化学反应合成向生物矿化与新生骨引导机理及硬组织再造技术方向发展。同时，羟基磷灰石在金属、陶瓷等植入体表面的涂层、以及天然材料制备羟基磷灰石依然是其合成研究的主要方向。     

纳米掺锶羟基磷灰石的制备及其抗菌性能研究

以硝酸钙、氯化锶、磷酸氢二氨等为原料,采用溶胶-凝胶-超临界流体干燥法,制备了纳米掺锶羟基磷灰石(SrHAP)。通过元素含量分析、TEM、XRD、FT-IR等手段对其结构进行了表征,分析了锶的掺入对羟基磷灰石(HAP)的结构、晶形及结晶度的影响;研究了HAP掺入锶后对大肠杆菌、金黄色葡萄球茵、乳酸杆菌的抗茵性能。结果表明:采用溶胶-凝胶-超临界CO_2干燥法,可制备结晶性较好的纳米HAP和Sr/[Sr ca]原子比为0．5的纳米SrHAP;在给定的条件下,锶可以按化学计量比掺入到HAP的结构中;HAP掺入锶后,其主要官能团红外光谱吸收峰的振动频率降低,晶形从HAP的短棒状改变为SrHAP的针状,结晶度降低,对大肠杆菌、金黄色葡萄球菌、乳酸杆茵的抗菌性能提高。     

HAP／UHMWPE生物复合材料的制备与微观结构

通过化学共沉淀．水热合成法制备纳米级羟基磷灰石（HAP），再用自制模具制备出羟基磷友石／超高分子量聚乙烯（UHMWPE）复合材料．通过SEM观察、X射线分析、DSC测试、热重分析以及力学性能测通过其超长分子链获得网状结构，为材料提供机械强度，HAP在复合材料中试，研究了HAP／／UHMWE复合材料的微观组织和力学性能．结果表明：UHMWPE分布比较均匀，并被包裹在UHMWPE超长细链形成的层层网状结构之中．随着HAP含量的增加，复合材料的熔点下降，熔融热焓有所降低，UHMWPE的结晶度降低了．随着HAP体积含量的增加，复合材料的拉伸强度和抗弯强度均下降，从30．1MPa降到21．5MPa以及从63．1IMPa降到46．7MPa，而弹性模量有所上升，从1．6GPa上升到4．1GPa．     

纳米羟基磷灰石合成的两种新方法

介绍了用溶剂热和微波辅助固相手段合成羟基磷灰石 (HAP)的两种新方法 ,得到了HAP纳米粒子和纳米棒。与传统水热合成法相比 ,溶剂热方法首次实现了在非水体系中纳米HAP的合成。微波固相合成法则得到了具有较好形貌和结构的HAP纳米粒子和纳米棒。该方法反应条件温和、反应时间极短、反应步骤简单且易于操作 ,因此有望实现HAP材料的大规模产业化。用X 射线衍射仪、扫描电子显微镜和红外光谱仪对产物的结构和形貌进行了表征。同时 ,也对微波固相反应的机理进行了初步探讨。     

Ag3PO4/羟基磷灰石复合光催化剂的制备及对亚甲基蓝的高效降解

以天然废弃物牡蛎壳为原料,利用沉淀法和水热法制备出高纯度的羟基磷灰石(HAP),负载Ag₃PO₄后制备出具有可见光响应的复合光催化剂Ag₃PO₄/HAP,并以亚甲基蓝（MB）为反应模型考察了不同催化剂的降解性能。利用SEM、TEM、XRD、BET、XPS、UV-Vis、电子自旋共振（ESR）等仪器对样品进行表征。结果表明,两种方法均可合成HAP材料,但水热法合成的材料纯度更高,且合成出了纳米等级的HAP;Ag₃PO₄的添加未改变HAP的组成和结构,却改善了材料对可见光的吸收性能。与沉淀法相比,水热法制备的HAP具有更好的吸附性能,其比表面积为46.63 m2·g-1;且随着Ag₃PO₄质量的增加,复合材料的比表面积逐渐增大。水热法制备的Ag₃PO₄/HAP表现出了较高的活性,其中1:2-Ag₃PO₄/HAP催化剂的表现更突出,在10 min时即可达到50%的降解率,并在40 min内达到完全降解;经自由基捕获实验证实,参与降解反应的主要活性物种为?O₂?和h+。      

Influence of the polysaccharide galactomannan on the dielectrical characterization of hydroxyapatite ceramic

Hydroxyapatite (HAP), Ca₁₀(PO₄)₆(OH)₂, has a wide range of biomedical applications because it is excellent biocompatibility and similar to natural bone tissue. The synthesis of the nanocrystalline powders of hydroxyapatite (HAP) was developed by the high energy method of dry mechanical alloying. The Ca(OH)₂ and CaHPO₄ were used in the preparation. Galactomannans are polysaccharides that occur in the endosperm of the seeds of leguminous plants as cell wall storage components was obtained from seeds of Adenanthera pavonina L. family Leguminosae (Fabaceae) and subfamily Mimosoideae. The nanocrystalline powders of hydroxyapatite were mixed with 10% (Gal 90), 20% (Gal 80) and 30% (Gal 70) of galactomannan. The aim of the study was to investigate influence of the galactomannan on the electrical characterization of bioceramic materials based on hydroxyapatite. The samples were studied by X-ray diffraction (XRD) was recorded to confirm the formation of a single phase solid solution and comportment this phase through the Rietveld analysis, scanning electron microscopy (SEM) and Dielectric measurements in the 10 Hz–100 MHz frequency range, at room temperature, have been performed. The presence of nanocrystals was confirmed by X-ray diffraction of HAP with size crystallite of 110 nm.     

Temperature dependence of magnetic property and photocatalytic activity of Fe3O4/hydroxyapatite nanoparticles

Fe₃O₄/hydroxyapatite (HAP) nanoparticles have been developed as a novel photocatalyst support, based on the embedment of magnetic Fe₃O₄ particles into HAP shell via homogeneous precipitation method. The resultant nanoparticles were characterized by transmission electron microscope (TEM) and X-ray diffraction (XRD). These particles were almost spherical in shape, rather monodisperse and have a unique size of about 25 nm in diameter. The effect of calcination temperature on magnetic property and photocatalytic activity of Fe₃O₄/HAP nanoparticles was investigated in detail. The obtained results showed that the Fe₃O₄/HAP nanoparticles calcined at 400 °C possessed good magnetism and photocatalytic activity in comparison with that calcined at other temperatures.     

Synthesis and sintering of nanocrystalline hydroxyapatite powders by citric acid sol-gel combustion method

The citric acid sol-gel combustion method has been used for the synthesis of nanocrystalline hydroxyapatite (HAP) powder from calcium nitrate, diammonium hydrogen phosphate and citric acid. The phase composition of HAP powder was characterized by X-ray powder diffraction analysis (XRD). The morphology of HAP powder was observed by transmission electron microscope (TEM). The HAP powder has been sintered into microporous ceramic in air at 1200 °C with 3 h soaking time. The microstructure and phase composition of the resulting HAP ceramic were characterized by scanning electron microscope (SEM) and XRD, respectively. The physical characterization of open porosity and flexural strength have also been carried out.     

Single-step rapid microwave-assisted synthesis of polyacrylamide-calcium phosphate nanocomposites in aqueous solution

Organic-inorganic polyacrylamide-calcium phosphate (PAM-CP) nanocomposites with calcium phosphate (CP) nanoparticles homogeneously dispersed in the polymer matrix have been successfully synthesized using calcium salt, phosphate and acrylamide monomer in aqueous solution by a single-step microwave-assisted method. When the experiment is conducted in a basic medium, the CP phase obtained consists of hexagonal hydroxyapatite (HAP) nanorods, and HAP nanorods are homogeneously dispersed in the polyacrylamide (PAM) matrix. While the preparation is in a weak acidic medium, the amorphous calcium phosphate (ACP) nanoparticles are formed and dispersed in the PAM matrix. The reported method has advantages of being simple, rapid, low-cost, and environmentally friendly. The products are characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric analysis (TG).     

Preparation of microstructured hydroxyapatite microspheres using oil in water emulsions

Hydroxyapatite (HAP) microspheres with peculiar spheres-in-sphere morphology were prepared by using oil-in-water emulsions and solvent evaporation technique. Ethylene vinyl acetate co-polymer (EVA) was used as the binder material. Preparation of HAP/EVA microspheres was followed by the thermal debinding and sintering at 1150°C for 3 h to obtain HAP microspheres. Each microsphere of 100–1000 μm was in turn composed of spherical hydroxyapatite granules of 2–15 (μm size which were obtained by spray drying the precipitated HAP. The parameters such as percentage of initial HAP loading, type of stabilizer, concentration of stabilizer, stirring speed and temperature of microsphere preparation were varied to study their effect on the particle size and geometry of the microspheres obtained. It was observed that these parameters do have an effect on the size and shape of the microspheres obtained, which in turn will affect the sintered HAP microstructure. Of the three stabilizers used viz. polyoxyethylene(20) sorbitan monopalmitate (Tween-40), sodium laurate and polyvinyl alcohol (PVA), only PVA with a concentration not less than 0.1 wt% showed controlled stabilization of HAP granules resulting in spherical microspheres of required size. Morphologically better spherical microspheres were obtained at 20°C. Increasing the stirring speed produced smaller microspheres. Smaller microspheres having size < 50 μm were obtained at a stirring speed of 1500 ±50 rpm. A gradual decrease in pore size was observed in the sintered microspheres with increase in HAP loading.     

The microstructure evolution of nanohydroxapatite powder sintered for bone tissue engineering

Nanotechnology has been widely used to overcome the brittleness of coarse ceramics. Laser sintering is an effective approach for the preparation of nanoceramics due to the laser properties such as high energy density and rapid heating. In this study, the nanohydroxypatite (HAP) was used to prepare for artificial bone scaffold using a home-made selective laser sintering (SLS) system. The microstructure and the properties of the sintered nanoHAP are tested with scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. We found that the shape of nanoHAP particle changes from long needle-like to spherical or ellipsoidal after sintering, and the HAP particles grow up until they merge together with the increasing temperature. The tendency of preferred orientation reduces and the degree of crystallinity increases with the growth of nanoHAP. HAP dehydroxylation occurs during sintering. HAP decomposes to tetracalcium phosphate and β-calcium phosphate when the sintering temperature is over 1354°C (the laser power is 8.75?W). Sintered nanoHAP maintains a high degree of crystalline and nanometre scale when the laser power is 7.50?W, spot radius 2?mm, sintering time 4?s and thickness of the layer is 0.2?mm. This study presented the optimised technology parameters for the preparation of nanoceramics with a novel SLS system and demonstrated that the nanoceramics with nanosize scale can be obtained by this system.