溶胶-凝胶法制备羟基磷灰石粉体

前言 羟基磷灰石[Ca10（PO4）6（OH）2]（简称HA）化学组成接近生物体骨质的矿物成分，具有良好的生物活性及生物相容性，可以用来修复损坏或者病变的硬组织，在整形外科及口腔修复方面得到了广泛的应用。人们探索了多种方法合成羟基磷灰石粉体，如固相反应法、化学沉淀法、水热合成法以及溶胶-凝胶（sol—gel）法等。     

纳米羟基磷灰石应用研究进展

羟基磷灰石是人体和动物骨骼的主要无机矿物成分,当羟基磷灰石的尺寸达到纳米级时将表现出一系列的独特性能。纳米羟基磷灰石具有良好的生物相容性和生物活性,是较好的生物材料,被广泛应用于骨组织的修复与替代技术,在生物医学领域具有非常广阔的应用前景。文章综述了纳米羟基磷灰石的应用研究,指出了目前纳米羟基磷灰石材料中存在的主要问题,并对纳米羟基磷灰石的发展前景进行了展望。     

医用双相磷酸钙陶瓷的制备工艺研究

医用双相磷酸钙（BCP）陶瓷是β-磷酸三钙（β-TCP）和羟基磷灰石（HA）的复合体,其成分与骨矿物组成类似。它具有良好的生物相容性,在生物医学领域具有非常广阔的应用前景。且在生理环境下能发生不同程度的降解,被组织吸收。通过化学沉淀法制备纳米羟基磷灰石,然后通过可溶性钙盐和磷酸盐反应工艺制得β-磷酸三钙,最后将二者进行机械复合而制得双相磷酸钙,将所得样品用X射线衍射仪（XRD）进行了表征。结果显示：所得的双相磷酸钙中掺杂有β-焦磷酸钙,但是它的结晶较好,并且可以改善双相磷酸钙陶瓷的力学性能。     

一种新型复合医用乳胶膜的制备及其生物学性能研究

将纳米羟基磷灰石与天然胶乳复合,制备出羟基磷灰石/天然胶乳复合医用乳胶膜。采用广角X射线衍射（XRD）和透射电子显微镜（TEM）对纳米羟基磷灰石进行表征,结果表明与人体内羟基磷灰石纳米晶非常相似。对羟基磷灰石/天然胶乳复合医用乳胶膜的力学性能、蛋白质含量以及生物相容性进行的测试表明这是一种非常有前途的医用复合材料,有望获得广泛应用。     

高纯羟基磷灰石材料的研制

高纯羟基磷灰石材料的研制郭斌，王志，任爱玲（河北轻化工学院环境工程系，石家庄０５００１８）羟基磷灰石（简称ＨＡＰ）是８０年代发展起来的供牙科和骨科使用的新型填补、移植材料。这种材料和其他同类用途材料相比，因为独具良好的生物相容性和成骨性而受到普遍重视...     

国外相纯净的α—活性磷酸三钙制备的应用

磷酸钙无机物是自然界存在的骨骼中最重要的无机成分，骨骼中大部分的磷酸钙是以羟基磷灰石或其变更形式如磷酸磷灰石（一种羟基磷灰石的碳酸盐取代型）存在的，当天然存在的骨骼遭到破坏或破裂时，经常希望用骨骼代用材料以替换损坏的骨骼，由于羟基磷灰石及其代用形式，无论在化学上还是结构上，与天然存在的骨骼中发现的磷酸钙无机物极其相似，因此骨骼的修补和更换，合成羟基磷灰石是有吸引力的材料。     

医用双相磷酸钙陶瓷的制备工艺研究

医用双相磷酸钙（BCP）陶瓷是β-磷酸三钙（β-TCP）和羟基磷灰石（HA）的复合体,其成分与骨矿物组成类似,在生理环境下能发生不同程度的降解,被组织吸收。通过化学沉淀法制备纳米羟基磷灰石,然后通过可溶性钙盐和磷酸盐反应工艺制得的β-磷酸三钙,最后将二者进行机械复合而制得双相磷酸钙,将所得样品用X射线衍射仪（XRD）对样品进行了表征。结果显示：所得的双相磷酸钙中掺杂有β-焦磷酸钙,但是它的结晶较好,并且可以改善双相磷酸钙陶瓷的力学性能。     

纳米羟基磷灰石/聚合物复合生物材料的制备方法研究进展

纳米羟基磷灰石是自然骨的主要组分之一,具有良好的生物相容性和生物活性,被广泛应用于骨组织的修复与替代材料。但是,由于材料本身力学性能较差制约了羟基磷灰石的进一步应用,且自然骨是由纳米羟基磷灰石和聚合物组成的天然复合材料,因此制备综合性能优越的羟基磷灰石/聚合物复合生物材料是当今研究的热点。综述了羟基磷灰石/聚合物复合生物材料的制备方法,并对其发展趋势进行了简单探讨。     

纳米羟基磷灰石的微波烧结

由Ca10(PO4)6(OH)2构成的羟基磷灰石（HA）是骨骼和牙齿的主要矿物成份。羟基磷灰石具有极好的生物相容性。常用于骨骼的移植，然而，由于这种陶瓷材料的脆性。使其应用受到一定的限制，已有研究表明，纳米晶体结构能提高陶瓷材料的机械性能，本文采用共沉淀法合成纳米羟基磷灰石，然后压成片状，通过微波烧结固化。试样于1100℃下，在短至30min内就能轻易烧结，密度达到理论值的97%，对烧后试样的微观结构分析表明，致密化后得到的晶体材料仍能保持纳米级尺寸。文中探讨了通过微波烧结法得到试样的相组成。微观结构和物理性能。     

电化学沉积-水热合成法制备羟基磷灰石生物涂层的工艺研究

采用电化学沉积法,在低温条件下从含钙、磷离子的电解水溶液中沉积磷酸钙涂层,经过水热合成获得羟基磷灰石（ＨＡ）涂层．用扫描电镜（ＳＥＭ）、Ｘ射线衍射（ＸＲＤ）和红外光谱（ＩＲ）对涂层的组织结构和化学组成进行分析．结果表明：电化学沉积涂层由ＣａＨＰＯ４·２Ｈ２Ｏ,经水热合成后转变为羟基磷灰石．随蒸气温度和压力的升高,羟基磷灰石的含量增加,在适当条件下可获得纯羟基磷灰石涂层．该方法重复性好,是制备羟基磷灰石生物涂层的理想方法之一．     

Study of microstructural,mechanical, and biomedical properties of zirconia/hydroxyapatite ceramic composites

In this study, hydroxyapatite was obtained by the sol-gel method, and zirconia/hydroxyapatite composites (YSZ/HAp) were produced with weight proportions of 95/5, 90/10, 85/15, and 80/20, respectively. The samples were characterized by X-ray diffraction (XRD), Archimedes' principle, Fourier-transform infrared spectroscopy (FT-IR), Vickers microhardness, scanning electron microscopy (SEM) and field emission scanning electron microscopy (FESEM). The calvarial critical-sized defect experimental model in rats was used to evaluate the biological interaction between YSZ/HAp scaffolds and bone tissue by Micro CT analysis. The XRD patterns of composites showed the major intensity of the zirconia phase and lower intensity of the hydroxyapatite phase, but the FT-IR analysis confirmed the presence of hydroxyapatite. Dense composite materials were verified by way of the Archimedes’ principle, where the YSZ/HAp 85/15 sample had lower apparent porosity (0.60%) and water absorption (0.10%). Vickers microhardness showed that composite material hardness decreased with the increase of hydroxyapatite, varying from 1367.43 to 711.37 HV. SEM images were possible to quantify the crack sizes in the indentations and to identify the elements presents by EDS, while FESEM was applied to analyze the morphology of the powders and microstructure of the composites. Among the composite studied, YSZ/HAp 85/15 and YSZ/HAp 80/20 samples were the compositions that demonstrated the best mechanical behavior with a fracture toughness of 9.2 and 9.3 MPa m^1/2, respectively. The YSZ/HAp scaffold showed an interaction with bone tissue. The percent bone volume (BV/TV, p < 0.001) and bone mineral density (BMD, p < 0.01) were significantly increased in Zirconia/hydroxyapatite scaffold.     

The influence of molecular weight on the properties of polyacetal/hydroxyapatite nanocomposites. Part 1. Microstructural analysis and phase transition studies

In this work the influence of molecular weight of three polyoxymethylene (POM) copolymers on the properties of (POM)/hydroxyapatite (HAp) nanocomposites for long-term bone implants have been investigated by various physicochemical methods. Electron microscopy observations confirmed uniform dispersion of HAp in the polymer matrix, whereby DSC results show that HAp influences the degree of crystallinity of POM matrix. Temperature modulated differential scanning calorimetry (TMDSC) was applied to study the melting and recrystallization processes of POM matrix—it was found that with decreasing of POM molecular weight the amout of reversible melting increases. WAXD results show no shift in 2θ for pure POM copolymers and all POM/hydroxyapatite nanocomposites, indicating that the addition of HAp does not change the hexagonal system of POM. For all three copolymers, Young’s modulus increases with increasing hydroxyapatite concentration, whereby elongation at break decreases. On the contrast, HAp concentration does not have a significant influence on the tensile strength.     

Biomimetic phospholipid polymers for suppressing adsorption of saliva proteins on dental hydroxyapatite substrate

To prevent infectious diseases induced by the adhesion of microorganisms and their metabolic products to dental implants, saliva protein adsorption, which induces the plaque deposition to the intraoral substrates should be inhibited. We used a water-soluble 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer to modify the surface of hydroxyapatite (HAp) substrate, the main component of dental implant surface. The MPC polymer containing a catechol group at the terminal of polymer chain and amino groups in the side chain was synthesized by mimicking the mussel adhesive protein. The MPC polymer containing 2% of the primary amino groups showed effective adhesion to the HAp substrate. Mucin, the dental plaque protein, adsorbs on the HAp surface; however, the MPC polymer modification could reduce this adsorption amount by more than 98% compared to the original HAp substrate surface. Thus, the treatment of the MPC polymer has potential to reduce oral infection due to plaque deposition.     

Chitosan Fibers Modified with HAp/β-TCP Nanoparticles

This paper describes a method for preparing chitosan fibers modified with hydroxyapatite (HAp), tricalcium phosphate (β-TCP), and HAp/β-TCP nanoparticles. Fiber-grade chitosan derived from the northern shrimp (Pandalus borealis) and nanoparticles of tricalcium phosphate (β-TCP) and hydroxyapatite (HAp) suspended in a diluted chitosan solution were used in the investigation. Diluted chitosan solution containing nanoparticles of Hap/β-TCP was introduced to a 5.16 wt% solution of chitosan in 3.0 wt% acetic acid. The properties of the spinning solutions were examined. Chitosan fibers modified with nanoparticles of HAp/β-TCP were characterized by a level of tenacity and calcium content one hundred times higher than that of regular chitosan fibers.     

Increasing the Crystallinity of Hydroxyapatite Nanoparticles in Composites Containing Bioaffinitive Organic Polymers by Mechanical Stressing

Crystallinity of hydroxyapatite (HAp) in bioaffinitive disperse systems was increased by a wet mechanochemical treatment at room temperature. Silk fibroin (SF) and/or hyaluronic acid (HYA) were used as bioorganics. With the mechanochemical treatment, the crystallite size and the aspect ratio of HAp decreased and became closer to that of swine trabecular bone. Mechanochemical effects on the HAp nanocrystals were discussed in terms of coherent chemical interaction between HAp and bioorganics.     

Biomolecular Template-Induced Biomimetic Coating of Hydroxyapatite on an SS 316 L Substrate

Bone, a natural composite, comprises non-stoichiometric calcium hydroxyapatite (HAp) precipitated in a controlled reaction environment of a highly aligned, anisotropic organic template (type I collagen) that leads to its exotic tensile and compressive strength. It differs from stoichiometric hydroxyapatite in composition, crystallinity, and other physical and mechanical properties. In the present study, functionalized biomolecular template-induced precipitation of HAp on an SS 316 L substrate following biomimetic route exhibits distinct alterations in crystal growth and geometry, which in turn indicates the potential of the process to develop a non-stoichiometric HAp coating on metal implants.     

In vitro evaluation of natural hydroxyapatite from Osteoglossum bicirrhosum fish scales for biomedical application

This study reports the obtainment of bioactive hydroxyapatite (HAp) extracted from scales of arowana fish (FSHA) (Osteoglossum bicirrhosum) by alkaline treatment followed by calcination at 600 and 800°C. The cell viability and bioactivity of hydroxyapatite particles (FSHA) were investigated and compared with those of HAp synthesized (s.HA) by the precipitation method. The HAp particles from fish scales showed non-toxic behavior to dental pulp stem cells similar to HAp synthesized. Additionally, bioactivity assays show that the Hap from natural source forms the bone-like apatite layer faster than s.HA sample, after being incubated in McCoy medium for 3 days. The results illustrate that HAp obtained from Osteoglossum bicirrhosum fish scale bio-waste showed excellent biocompatibility. Besides, this study provides an effective method for converting low-cost bio-waste into a value-added and it can be a potential alternative biomaterial for various biomedical applications.     

Pilot-scale manufacturing of phase-pure and highly crystalline hydroxyapatite: Lessons learned and process protocols

The recognition of hydroxyapatite (HAp) as the major bone mineral triggered significant research in bone tissue engineering applications. Although laboratory-scale development involves the synthesis of HAp in different routes, scalability with uncompromised quality remains a major challenge. This article reports a large-scale wet precipitation-based synthesis of phase-pure HAp using indigenously customized stirred tank reactors. The different synthesis parameters, like pH, reaction time, stirring rate, precursor addition, were tailored, together with the post-synthesis mechano-chemical treatment (aging induced Ostwald ripening) and calcinations, as the technology is matured to manufacture HAp powders in large volume. At least three batches of HAp were produced in the pilot-scale reactor with reproducible values of phase purity, compositional fingerprint, particle size distribution, flowability, etc. The post-calcination bluish tint was strategically addressed by adopting a proprietary calcination protocol. This batch process can produce around 200 kg/month of phase-pure and highly crystalline (91–94%) HAp using stirred tank reactors of different working volumes. Extensive scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses reveal the particle size of as-synthesized HAp powders with hexagonal crystal structure in the range of 20.47 ± 4.95 nm , while individual crystallite size in range of 22.3 ± 3.2 nm (XRD based Debye-Scherrer analysis). TEM-based SADP analysis confirms the highly crystalline hexagonal structure of as-synthesized HAp. The spray-dried powders with spherical shape having narrow size distribution (35–40 μm) could also be manufactured in large batches. The spray-dried HAp powders could be coated on clinically used stainless steel femoral stem implants using atmospheric plasma spray coating technique.     

Effect of Chondroitin Sulfate on the Crystal Growth of Hydroxyapatite

The effect of chondroitin sulfate (ChS) templates on the crystal growth of hydroxyapatite (HAp) was investigated. HAp particles and 60HAp/40ChS hybrid (in wt%) were synthesized by using a precipitation method with a calcium hydroxide suspension and phosphoric acid solutions without and with ChS, respectively. The sizes of HAp crystals formed without ChS templates were around 75 nm × 10 nm while those with ChS templates were around 12 nm × 6 nm. The inhibitory effect of ChS templates on the crystal growth of HAp is explained in terms of organic matrix regulated HAp formation following steric hindrance by adjacent crystals.     

Polyoxymethylene‐homopolymer/hydroxyapatite nanocomposites for biomedical applications

In this article, new polyoxymethylene (POM)/hydroxyapatite (HAp) nanocomposites for bone long‐term implants have been obtained and characterized by using FTIR, WAXD, SEM, TG, DSC, tensile tests, and in vitro evaluation. Characteristic bands both for extended chain crystals (ECC) and folded chain crystals (FCC) were observed in FTIR profiles for both pure POM and POM in POM/HAp nanocomposites. From WAXD analysis it has been found that the addition of HAp does not change the hexagonal system of POM in POM/HAp nanocomposites. Moreover, degree of crystallinity of POM increases with an increase of HAp content up to 1.0% and next decreases with an increase HAp content. It indicates that HAp nanoparticles up to 1.0% content act as effective nucleating sites. Mechanical tests revealed that Young's modulus increases, whereby, elongation at break and tensile strength decrease with increasing hydroxyapatite concentration. Results of in vitro investigations show that an increase of HAp content in POM nanocomposites facilitates formation of apatite layer on the sample surface and improves in vitro stability POM/HAp nanocomposites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012