天然高分子基复合骨支架研究进展

在生物医用材料中,天然高分子因具有良好的生物相容性和生物识别性而受到极大的关注。天然高分子与羟基磷灰石(HA)、生物活性玻璃(BG)、双相磷酸钙(BCP)等陶瓷材料复合形成的骨支架成为了骨组织再生领域的研究重点。综述了近年来天然高分子基复合骨支架的研究进展及其发展方向,并详细介绍了胶原、明胶、壳聚糖与不同陶瓷材料复合形成的骨支架在骨组织再生中的成效。     

碳磷灰石的制备和性能研究

羟基磷灰石(HA)被认为是目前最有吸引力的骨组织替代材料,与纯HA相比,碳磷灰石(CHA)在化学组成上更接近于人骨和牙齿等硬组织,且具有更好的生物相容性和更高的骨传导性,因此有望成为新型的骨组织替代材料.综述了目前国内外关于碳磷灰石的研究,主要介绍了CHA中碳酸根的取代类型、机理及制备方法,碳酸根的取代对HA结构及各方面性能的影响,以及碳酸根含量的测定等,并指出仿生法合成CHA及其复合材料是最新的研究热点,也是今后骨植入材料研究中的一个重要方向.     

生物陶瓷及其复合材料表面诱导类骨磷灰石层形成的研究

钙磷生物材料表面类骨磷灰石层的形成对其植入体内诱导新骨生成起非常重要的作用.本实验采用2倍模拟体液(2×SBF)为介质,通过仿生浸泡的方法研究了羟基磷灰石(HA)陶瓷及其复合材料羟基磷灰石/聚乳酸(HA/PLA)、羟基磷灰石/聚己內脂(HA/PCL)、羟基磷灰石/丝素(HA/SF)和羟基磷灰石/壳聚糖(HA/CS)表面诱导类骨磷灰石层形成的差异.实验结果表明,HA陶瓷及其复合材料在2×SBF溶液中仿生浸泡7d后,各样品表面均有一层厚度不同的类骨磷灰石层生成.并且该类骨磷灰石层的结晶度较低,晶粒较细(15～30nm),与人体自然骨无机物的结构非常类似.其中,在这4种复合材料中,HA/CS和HA/SF复合材料中因丝素蛋白和壳聚糖富含多种功能基团,能有效促进类骨磷灰石晶体的形核和生长,因而诱导类骨磷灰石生成的能力最强,显示其良好的生物活性.     

生物聚氨酯/羟基磷灰石微相分离与形状记忆性能

形状记忆功能化生物聚氨酯在医用植入体材料中备受关注,而聚氨酯的形状记忆性能与其微相分离结构密切相关。文中以可降解聚己内酯二醇(PCL-diol)、脂环形异佛尔酮二异氰酸酯(IPDI)、1,4-丁二醇(BDO)为单体通过两步法合成生物聚氨酯(PU),以溶液共混的方式加入PU基体中,制备了一系列聚氨酯/羟基磷灰石(PU/HA)复合材料。通过场发射扫描电子显微镜、傅里叶变换红外光谱、热失重分析和动态力学热分析等不同表征方法研究了HA的引入对PU基体微相分离的影响,及其与宏观形状记忆性能的关系,并考察了材料的生物安全性。结果表明,HA的引入明显促进了PU的微相分离,随着HA含量的增加,硬段与软段的玻璃化转变温度差值越大,表明微相分离程度越高。在HA质量分数低于15%时,HA的含量越高,形状回复越快,表明微相分离程度越高,形状记忆性能越好。L929细胞毒性测试结果显示,PU/HA具有良好的细胞安全性,在医用骨修复领域有潜在的应用价值。     

粉体材料相关知识

正羟基磷灰石(HA)是一种具有良好应用前景的无机生物矿物材料,它是人体和动物骨骼的主要无机成分,因此具有良好的环境相容性和生物活性,在生物医用材料、环境功能材料、湿敏半导体材料、催化剂载体以及抗菌功能材料等方面有着广泛的应用。多孔羟基磷灰石是通过某种制作工艺,在制备羟基磷灰石生物陶瓷过程中使其内部具有多孔的结构。多孔结构的羟基磷灰石除具有一般陶瓷的优良性能外,因具有大孔和微孔结构而具有骨传导性,植入人体后,将被体液溶解和组     

羟基磷灰石/淀粉基复合生物材料

淀粉基(starch-based)材料是一类重要的生物降解聚合物,羟基磷灰石(HA)是人体骨骼的主要成分,以淀粉基材料为基体、以HA为增强材料的HA/淀粉基复合材料是一类新型的复合生物材料,其具有良好的生物相容性,在骨修复领域具有巨大的应用潜力.初步对该复合材料进行了归类,并介绍了其制备工艺、性能和应用等方面的研究近况,指出改进复合工艺、采用纳米级HA增强并进行表面改性是其发展趋势.     

壳聚糖/羟基磷灰石骨修复材料的研究进展

首先概述了骨组织的成分、结构及功能,继而分别介绍了壳聚糖和羟基磷灰石的结构与性质,包括生物相容性、降解性、抗菌性、骨传导性等,综述了壳聚糖/羟基磷灰石复合材料的制备方法、力学性质、生物性能及研究现状,并对载药骨修复材料的研究作了简要介绍,最后展望了壳聚糖/羟基磷灰石骨修复材料在未来的发展前景.     

羟基磷灰石/钛合金骨替代材料体内生物结合性研究

通过动物植入实验,对具有羟基磷灰石涂层的钛合金(HA/Ti)与未经过表面改性的钛合金两种骨替代材料进行生物结合性的研究及评价.实验结果表明,两种骨替代材料与组织结合紧密,并且皮下植入后引起的炎反应为轻度.而具有羟基磷灰石涂层的钛合金实验样品效果更明显,说明羟基磷灰石/钛合金骨替代材料具有更好的生物结合性,是一种良好的骨替代材料.     

n-HA晶体及n-HA/PA66复合材料与人皮质骨的定性和定量对比研究

用TEM、XRD、FT-IR、TG-DTA等测试手段对成熟的人股骨皮质骨、纳米羟基磷灰石n-HA及n-HA／聚酰胺66(PA66)复合材料的形貌、相组成、晶胞参数、微晶尺寸分布、微观应变、特征基团和离子以及组成等进行了定性和定量表征。提出了一种简单易行的制样方法以获得较为清晰的人骨磷灰石照片。定量比较了人骨与两种材料中磷灰石晶体的结构差异。结果表明，n-HA和n-HA／PA66均具有较高的仿生性能。n-HA和n—HA／PA66中磷灰石的结晶度高于人骨磷灰石，晶格较人骨磷灰石完善，晶格畸变程度较人骨磷灰石小，并且两者中水分含量和CO3^2-含量均低于人骨。本文的研究对于进一步优化现有的骨修复替代材料和进一步开发更接近于人骨的骨修复替代材料具有重要意义。     

热喷涂生物陶瓷涂层的研究进展

采用热喷涂技术在金属(合金)基材表面制备的生物陶瓷涂层, 兼具金属材料较高力学强度和陶瓷材料优良生物学性能, 作为骨植入材料的研究和应用备受关注。本文介绍骨植入涂层材料的研究概况, 重点阐述热喷涂羟基磷灰石(HA)涂层的研究现状, 并概述新型生物活性硅酸钙陶瓷涂层的研究进展。     

羟基磷灰石涂层人工关节应用研究

对羟基磷灰石的成骨效应进行了研究，对添加骨水泥不当而导致的羟基磷灰石涂层人工关节涂层脱落进行了分析。结果表明，对于羟基磷灰石涂层人工关节，应有涂层区和非涂层区，骨水泥只能在非涂层区填充，而在涂层区则应使羟基磷灰石涂层直接与骨组织接触。这种人工关节，不仅充分利用了羟基磷灰石良好的生物相容性和成骨效应，而且有利于手术后的短期机械固定和长期的生物固定。     

Nanostructure and Properties of a Shinbone

Scanning electron microscope (SEM) observation shows that a shinbone is composed of large-volume-fraction hydroxyapatite and small-volume-fraction collagen protein materials. The hydroxyapatite is of laminated structure and consists of numberless hydroxyapatite sheets. The observation also shows that the hydroxyapatite sheets are parallel with each other and of nanometer scale. The high fracture toughness and fracture strength of the bone are investigated based on the calculation formula of the dissipation work and Griffith criterion. The investigated results reveal that the large-volume fraction and the nanometer scale of the hydroxyapatite sheets are the important factors to the high mechanical performance of the bone.     

常压下纳米级羟基磷灰石针状晶体的合成

通过使用一种易于重复的合成工艺,在常压下制备了纳米级羟基磷灰石针状晶体,这种纳米级针状晶体在形态,结构和组成上与人骨组织中纳米针晶非常相似,利于发挥羟基磷灰石优良的生理相容性,能用于研制一种类骨的高强柔韧的复合人工骨修复材料,所用的制备工艺有助于简化这种类骨复合材料的合成。     

Bone ingrowth in zirconia and hydroxyapatite scaffolds with identical macroporosity

The role of the material composition, porosity and surface topography of scaffolds for promotion of osteogenesis and osseointegration is not fully understood. The aim of the present study was to evaluate the effects of material composition and surface topography on bone ingrowth and bone contact. Designed macroporous ceramic scaffolds of zirconia and hydroxyapatite were used. Using free form fabrication (FFF) techniques an identical macroporosity in both materials was achieved. The scaffolds were implanted in rabbit tibia (cortical bone) and femur (trabecular bone). After 6 weeks of implantation the tissue response was assessed with histology and histomorphometry. The results showed significantly more bone ingrowth and bone contact in the hydroxyapatite scaffolds compared to the zirconia scaffold. Surface topography had no significant effect on bone contact inside the macropores regardless of material. This was observed in both cortical and trabecular bone sites. The study suggests that the difference between hydroxyapatite and zirconia was due to a difference in material chemistry.     

Granules of osteopatite and glass-reinforced hydroxyapatite implanted in rabbit tibiae

Granules of a modified hydroxyapatite, glass-reinforced hydroxyapatite composite and commercial hydroxyapatite were implanted in rabbit tibiae. Histological studies were carried out after 1 and 2 months implantation periods using light and fluorescence microscopy. A much higher percentage of bone contact was developed for both the glass-reinforced hydroxyapatite composite and the modified hydroxyapatite when compared to commercial hydroxyapatite (89–91% versus 66%) after 2 months implantation. The mechanism of bone formation and growth around implants is discussed in terms of the influence of elements incorporated into these novel materials which are commonly found in bone tissues, such as Na, K and Mg, and the presence of a soluble -tricalcium phosphate phase in the microstructure of the composite.This paper was accepted for publication after the 1995 Conference of the European Society of Biomaterials, Oporto, Portugal, 10–13 September.     

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。     

An <Emphasis Type="Italic">in vivo</Emphasis> study of a bone grafting material consisting of hydroxyapatite and reconstituted collagen

This study aims to evaluate the performance of our recently developed microspheres of hydroxyapatite/reconstituted collagen as a bone grafting material. The microspheres were fabricated into a circular disc and implanted in a pre-drilled hole in a rats calvaria. The bone tissue had regenerated and grown into the disc bone graft 4 weeks following implantation. After 16 weeks of implantation, the regenerated bone had integrated with the remaining material and made close contact with it. The disc had been completely absorbed with almost no visible bone graft left after 24 weeks of implantation. In contrast, a hydroxyapatite disc still remained intact on the 24th week after implantation. These results suggested that the hydroxyapatite/reconstituted collagen microsphere can be used as an excellent bone grafting material.     

Amino acid-assisted synthesis of strontium hydroxyapatite bone cement by a soft solution freezing method

Among many cations that can substitute for calcium in the structure of hydroxyapatite, strontium provokes an increasing interest because of its beneficial effect on bone formation and prevention of bone resorption. Strontium-incorporated calcium phosphates show potential in biomedical application, particularly the doped strontium may help in new bone formation. We have synthesized strontium hydroxyapatite powders at 2 °C by a soft solution freezing method using glycine as the template. The structural and morphological characterizations were carried out on the as obtained powders using Fourier transform infrared spectroscopy, X-ray diffraction analysis and scanning electron microscopy techniques. Strontium was quantitatively incorporated into hydroxyapatite where its substitution for calcium provoked a linear shift of the infrared absorption bands of the hydroxyl and phosphate groups. The strontium substituted bone cement has potential for use in orthopaedic surgeries. The present study shows that the addition of glycine plays an important role in reducing the particle size of strontium hydroxyapatite which could be used for biomedical applications.     

生物陶瓷增韧前后的比较研究

通过扫描电子显微镜对氧化锆增韧的羟基磷灰石和纯羟基磷灰石的裂纹扩展和断口形貌特征的观察，发现增韧的羟基磷灰石是以沿晶方式断裂，而纯羟基磷灰石是以解理方式断裂。本文分析了造成增韧前后两种材料不同断裂方式的机制，并讨论了颗粒增韧生物陶瓷的机理。     

In situ annealing of hydroxyapatite thin films

Hydroxyapatite is a bioactive ceramic that mimics the mineral composition of natural bone. Unfortunately, problems with adhesion, poor mechanical integrity, and incomplete bone ingrowth limit the use of many conventional hydroxyapatite surfaces. In this work, we have developed a novel technique to produce crystalline hydroxyapatite thin films involving pulsed laser deposition and postdeposition annealing. Hydroxyapatite films were deposited on Ti–6Al–4V alloy and Si (100) using pulsed laser deposition, and annealed within a high temperature X-ray diffraction system. The transformation from amorphous to crystalline hydroxyapatite was observed at 340 °C. Mechanical and adhesive properties were examined using nanoindentation and scratch adhesion testing, respectively. Nanohardness and Young's modulus values of 3.48 and 91.24 GPa were realized in unannealed hydroxyapatite films. Unannealed and 350 °C annealed hydroxyapatite films exhibited excellent adhesion to Ti–6Al–4V alloy substrates. We anticipate that the adhesion and biological properties of crystalline hydroxyapatite thin films may be enhanced by further consideration of deposition and annealing parameters.