孔结构渐变聚己内酯/羟基磷灰石仿生骨材料

为获得具有类似人骨的渐变孔结构、力学性能良好的羟基磷灰石(hydroxyapatite,HA)/聚己内酯(polycaprolactone,PCL)仿生骨材料,采用水热法制备了HA粉末,通过溶剂共混法将其与PCL复合,并采用浇铸/NaCl微粒浸出法制备了多孔状HA/PCL复合材料.通过控制造孔剂NaCl的粒径和用量得到了不同孔径、不同孔隙率的HA/PCL复合材料及具有渐变孔结构的HA/PCL复合材料.利用光学显微镜观察了其孔结构,结果为孔径在100～300μm,最大孔隙率达到80%.同时研究了它们在人体体温附近(37±5)℃的力学性能,结果表明渐变孔结构的HA/PCL复合材料的力学性能较单一孔结构的HA/PCL复合材料有了很大的提高.通过梯度造孔不仅可获得与人骨极为类似的多孔仿生材料,同时还可大幅提高多孔材料的力学性能.     

表面多孔Ti-羟基磷灰石/Ti-Ag生物梯度复合材料的制备与性能

采用放电等离子烧结技术制备表面多孔Ti-羟基磷灰石（HA）/Ti-Ag生物梯度复合材料,研究了不同HA含量对复合材料微观结构、界面结合、表面孔隙特征、力学性能及体外生物活性的影响及机制。结果表明,表面多孔Ti-HA/Ti-Ag复合材料中间基体合金主要由α-Ti和Ti₂Ag相组成,表面多孔层主要由α-Ti和HA相组成,同时还存在少量CaO、CaTiO₃、Ti₅P₃等反应相;表面多孔Ti-HA/Ti-Ag复合材料中间基体与表面多孔层形成稳定的冶金结合,但随着HA含量增加,反应相增多,界面结合变差,表面孔隙率和平均孔径呈增大趋势,导致平均抗压强度减小且弹性模量降低,因此过高的HA含量会导致材料力学性能下降;体外生物活性实验表明,表面多孔Ti-HA/Ti-Ag复合材料在人工模拟体液中浸泡7天后表面生成大量类骨磷灰石层,并且随着HA含量的增大,磷灰石形成能力明显增强。      

HA改性短切碳纤维/PMMA生物复合材料力学性能的研究

采用原位合成与溶液共混的方法,制备了纳米羟基磷灰石(HA)-短切碳纤维（C_f）/聚甲基丙烯酸甲酯(PMMA)生物复合材料, 研究了HA对HA-C_f/PMMA复合材料的力学性能和微观结构的影响. 采用万能材料试验机测试了HA-C_f/PMMA复合材料的力学性能,用X射线衍射仪（XRD）、透射电镜（TEM）、场发射扫描电子显微镜（FESEM）和红外吸收光谱仪(FT-IR)分析测试手段对材料的组成结构及断面的微观形貌等进行了测试和表征. 结果表明,采用卵磷脂改性后的HA纳米片与PMMA基体的界面结合性能得到了有效改善,显著提高了复合材料的力学性能;随着HA含量的增加,HA-C_f/PMMA复合材料的弯曲强度、拉伸强度、压缩强度、弯曲模量和拉伸模量均呈先增大后减小的趋势. 当HA含量在8wt%时,复合材料的力学性能最佳.     

磷酸单酯偶联剂改性羟基磷灰石/ 高密度聚乙烯复合人工骨材料的制备和性能

采用磷酸单酯偶联剂对羟基磷灰石( HA) 进行表面改性处理, 通过熔融共混复合等工艺制备了改性HA/ 高密度聚乙烯( HDPE) 复合人工骨材料。用IR、TGA 和燃烧实验对复合材料的结构和组成进行了表征, 并对复合材料的流变性能、热稳定性、力学性能进行了初步研究。结果表明,所制备的改性HA/ HDPE 复合材料比未改性HA/ HDPE 具有更好的流变性能和机械力学性能, 组成均一, 具有良好的热稳定性, 通过控制复合材料中改性HA 及HDPE 配比, 可制备出机械力学性能优良的复合人工骨材料, 在生物医学材料研究中具有重要意义。      

新型HA/Ti-Fe生物复合材料的制备及其性能研究

采用无压烧结制备出不同Ti-Fe含量的HA/Ti-Fe生物复合材料,对其组织结构和力学性能进行了研究.显微组织的观察表明:均匀分布于HA基体中的金属Ti-Fe增强颗粒呈一种新颖的蛋壳状组织结构,其中核区主要由Fe组成,壳层主要由Ti组成.力学性能测试结果显示:随着Ti-Fe含量的增加,HA/Ti-Fe复合材料的硬度有所下降,但材料的抗弯强度和断裂韧度均明显提高.当Ti-Fe含量为5％时,抗弯强度出现最大值93MPa,与纯HA相比提高了42％;当Ti-Fe含量为15％时,材料的断裂韧度达到最大值1.3MPa·m1/2,较纯HA提高了128％.良好的界面结合和分布于壳层的韧性相Ti是导致材料力学性能大幅提高的主要原因.     

多孔ZnO/羟基磷灰石生物复合材料的制备与性能

利用放电等离子烧结技术制备多孔ZnO/羟基磷灰石（HA）生物复合材料,研究不同纳米ZnO含量对ZnO/HA复合材料微观结构、孔隙特征、力学性能、矿化和降解性能的影响。结果表明:烧结后ZnO/HA复合材料主要由HA相和ZnO相组成;随着ZnO含量提高,多孔ZnO/HA复合材料孔隙率缓慢增大,抗压强度略有减小,弹性模量变化不大;多孔ZnO/HA复合材料的孔隙率>40%,孔径在50～500 μm之间,抗压强度>148 MPa,弹性模量为6.5 GPa左右,能够满足骨修复材料的要求;模拟人工体液中矿化和降解实验表明,多孔ZnO/HA复合材料浸泡7天后表面开始形成大量类骨磷灰石层,且随着ZnO含量增加,磷灰石形成能力明显增强而降解速率加快。      

用仿生自组装法制备的新型生物复合材料及表征

通过仿生自组装法在室温下制备了纳米碳酸化羟基磷灰石/胶原(nCHAC)复合材料,并采用X射线衍射(XRD)、热分析(TGA)和透射电镜(TEM)进行了观察和分析.结果表明,该材料具有与天然骨相同的纳米尺度和胶原蛋白无机相,含有(2.8～14.7)w%的碳酸化HA成分;其显微结构是矿化的胶原纤维束,类似于天然骨的分级结构.揭示了碳酸化HA和胶原含量不同的复合材料中,具有微小差别的自组装单元.碳酸的百分含量影响矿物的晶体尺寸和胶原纤维的组装.因此,nCHAC复合材料是有前途的硬组织修复用材料,其所具有的特殊性能要归功于生物仿生制备出的nCHAC材料有与天然骨类似的成分和类似的微观结构.     

原位增强羟基磷灰石/壳聚糖复合棒材

利用低温水溶液均相沉积法制备了磷酸钙盐微纤维; 应用原位沉析法制备了壳聚糖(CS)三维棒材及羟基磷灰石(HA*)/CS复合棒材。XRD证实应用原位沉析法制备HA*/CS复合棒材过程中, 磷酸钙盐转化为羟基磷灰石结构, 尺寸为10~60 μm, 并用SEM对晶体形貌进行了表征, 分析了转化机制。HA*/CS复合材料的微观形貌表明, HA*晶体在CS凝胶棒原位沉析的过程中析出而与CS基体形成镶嵌、 相互咬合结构, 且在基体中分散均匀, 有效地提高了HA*与CS基体的界面连接作用, 使力学性能显著提高。所制备的HA*/CS棒材随HA*含量的增大(在其饱和溶解度3.3 wt%范围内), 复合材料的弯曲性能逐渐提高, 当羟基磷灰石质量分数为3.3%时, 复合材料的弯曲强度达到159.6 MPa, 弯曲模量达到5.1 GPa, 比CS基体分别提高85.6%和54.5%。HA*/CS复合棒材的弯曲强度和弯曲模量远高于松质骨, 弯曲强度也比密质骨高。      

HA/HDPE多尺度生物复合材料的制备与力学性能

采用原位矿化复合-固相挤出技术制备羟基磷灰石/高密度聚乙烯(HA/HDPE)复合材料。结果表明,原位矿化-固相挤出制备的HA/HDPE复合材料是一种纳米HA颗粒均匀分散、界面结合强度高、HA/HDPE复合纤维定向排列的多尺度结构复合材料,在纳米尺度上HA均匀分散在HDPE基体中,在微米尺度上形成HA/HDPE复合纤维,在显微尺度上定向排列的HA/HDPE复合纤维形成织构结构。该HA/HDPE多尺度结构复合材料的力学性能与传统的熔融挤出的HA/HDPE复合材料相比有显著提高,拉伸强度达到245MPa,弯曲强度达到165MPa,拉伸模量为18.1GPa,力学性能均达到人体皮质骨的力学要求。     

PES/HA多孔生物材料的制备及其生物相容性

制备PES/HA复合材料,红外光谱分析显示该复合材料主要是物理结合;以氯化铵为制孔剂,制备复合材料与制孔剂质量比为1∶0.25,1∶0.5,1∶0.75,1∶1的多孔复合材料。测定PES/HA孔结构复合材料吸水率。当复合材料与制孔剂质量比为1∶0.25时吸水率为40%。制孔剂含量比例越高,复合材料吸水率越高,当复合材料与制孔剂质量比为1∶1时PES/HA复合材料吸水率为88%。通过光学显微镜和电镜比较发现4组复合材料孔径多数分布在200~300μm之间,最小孔径约为40μm,最大孔径约为470μm;体外培养MG-63细胞,通过噻唑蓝(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltet razolium bromide,MTT)研究PES/HA复合材料对细胞毒性的影响,PES/HA复合材料毒性级别为I,该材料对MG-63细胞无毒性,这种细胞在PES/HA多孔材料表面和孔结构中粘附良好,细胞伸出多个伪足贴附在材料表面及孔壁上。     

热致液晶聚酯/聚醚醚酮复合纤维的制备与表征

将热致液晶聚酯(VA)与聚醚醚酮(PEEK)共混后,通过熔融纺丝制备了热致液晶聚酯/聚醚醚酮复合纤维,并对复合纤维的热性能、聚集态结构、相态结构和力学性能进行了研究。结果表明,VA的加入能够降低PEEK纤维的玻璃化温度和冷结晶温度,同时PEEK的结晶温度也随着VA的加入而升高;VA的加入有利于提高PEEK的结晶性能,使得PEEK晶粒尺寸变大,晶面间距变小,晶体更加完善,晶区取向增强;随着VA添加量的增大,VA相逐渐由球状或椭球状向微纤状变化;随着喷丝头拉伸比的增大,VA相的长径比呈现先增大后减小的趋势;添加1%和2%的VA后,复合纤维的断裂强度有少许下降,而当VA的添加量增大到4%后,复合纤维的总拉伸倍数提高,并且断裂强度有一定的提升。     

Hydrothermal-electrochemical codeposited hydoxyapatite/yttria-stabilized zirconia composite coating

Hydroxyapatite(HA)/yttria-stabilized zirconia(YSZ) composite coatings were deposited on titanium substrates using a hydrothermal electrochemical method in an electrolyte containing calcium, phosphate ions and YSZ particles. HA/YSZ composite coatings were prepared in different conditions with different electrolyte temperatures(100 ∼ 200°C), current densities(0.1 ∼ 10.0 mA/cm²), and particles content in bath(0 ∼ 100 g/L). The effect of YSZ additions on the phase composition, microstructure, thermal stability, corrosion behavior and the bonding strength of HA/YSZ composite coatings were studied. The results show that crystallinity of HA in HA/YSZ composite coatings increase continuously with the electrolyte temperature and close to stoichiometric HA. The n(Ca)/n(P) ratio at 200°C is about 1.67 according with stoichiometric HA. YSZ particles are imbedded uniformly between the HA crystals. The average HA crystal size are reduced owing to the additions of YSZ particles. After annealing at 1200°C, tetragonal phase YSZ tend to react with the released CaO to form cubic phase YSZ and CaZrO₃, which cause destabilization of HA to decompose into more α-TCP phase. The bonding strength between HA/YSZ composite coatings and titanium substrates increase with increasing volume content of YSZ in the composite coatings (V %). HA/YSZ composite coatings exhibit a better electrochemical behavior than pure HA coatings and uncoated Ti metals.     

玻璃纤维/环氧树脂复合材料与镀层界面的Ni颗粒强化工艺

针对玻璃纤维/环氧树脂复合材料与镀层结合界面强度低的问题,基于复合材料/镀层间的机械互锁原理及传统塑料基体化学镀工艺,提出通过增强颗粒的桥接作用,增加含有增强颗粒的过渡层来强化镀层界面的复合材料金属化方法。对金属化后的玻璃纤维/环氧树脂复合材料试件采用拉伸试验法测量镀层的结合强度,并通过截面和断面的显微观测,分析了增强颗粒对于镀层界面的强化机制;同时获得了玻璃纤维/环氧树脂复合材料表面粗糙度和增强颗粒质量分数对含有过渡层的镀层结合强度的影响规律。结果表明:采用上述金属化方法可以显著提高镀层的界面强度,与传统的金属化工艺制备试件相比,玻璃纤维/环氧树脂复合材料在不同表面粗糙度下,镀层结合强度平均提高161%;同时,镀层的结合强度随着增强颗粒质量分数的增加,呈现先增大后减小的趋势,当增强颗粒的质量分数为50%时,镀层的结合强度达到最大。      

OTS-modified HA and its toughening effect on PLLA/HA porous composite

In this paper, hydroxyapatite (HA) particles was modified with long-chain organic silane-Octadecyltrichlorosilane (OTS), and the modified particles were further used for preparing Poly(l-lactic acid) PLLA/HA porous composite. The modified particles were characterized by means of XRD, FTIR, and XPS techniques. Both XPS and FTIR results showed that OTS had been combined with HA, and the formation of P–O–Si bond, a covalent bond, on the HA particle surface was confirmed by XPS. OTS-modified HA particles were used to prepare porous composites by thermally induced phase separation method. The results showed that the composite had an interconnected pore structure with 100–300 μm macropores. With OTS dosage increasing during modification, the mechanical properties of PLLA/OTS-modified HA porous composites increased obviously. These results showed that OTS modification can effectively improve the interface compatibility between HA surface and PLLA.     

Characterization of poly(3-hydroxybutyrate)/nano-hydroxyapatite composite scaffolds fabricated without the use of organic solvents for bone tissue engineering applications

Poly(3-hydroxybutyrate)/nano-hydroxyapatite (PHB/nHA) composite scaffolds were fabricated without the use of organic solvents at different mass fractions of HA nanoparticles. HA nanoparticles were homogeneously dispersed as primary particles in the polymer matrix of the scaffolds at 10 and 15 wt.% nHA content. Agglomeration of HA nanoparticles occurred when the nHA content of the scaffolds reached 20 wt.%. All the scaffolds had high porosities with interconnected porous structure and optimized pore size ranges. Mechanical properties of all the scaffolds were in the range of mechanical properties of cancellous bone. Scaffolds were biocompatible to MG-63 cells in the indirect method of cytotoxicity evaluation. Also, the morphology of the attached MG-63 cells in direct contact with the scaffolds indicated the appropriate cell-scaffold interaction. Thus, the PHB/nHA composite scaffolds investigated in this study tend to be favorable for bone tissue engineering applications.     

Improve the Strength of PLA/HA Composite Through the Use of Surface Initiated Polymerization and Phosphonic Acid Coupling Agent

Bioresorbable composite made from degradable polymers, e.g., polylactide (PLA), and bioactive calcium phosphates, e.g., hydroxyapatite (HA), are clinically desirable for bone fixation, repair and tissue engineering because they do not need to be removed by surgery after the bone heals. However, preparation of PLA/HA composite from non-modified HA usually results in mechanical strength reductions due to a weak interface between PLA and HA. In this study, a calcium-phosphate/phosphonate hybrid shell was developed to introduce a greater amount of reactive hydroxyl groups onto the HA particles. Then, PLA was successfully grafted on HA by surface-initiated polymerization through the non-ionic surface hydroxyl groups. Thermogravimetric analysis indiated that the amount of grafted PLA on HA can be up to 7 %, which is about 50 % greater than that from the literature. PLA grafted HA shows significantly different pH dependent ζ-potential and particle size profiles from those of uncoated HA. By combining the phosphonic acid coupling agent and surface initiated polymerization, PLA could directly link to HA through covalent bond so that the interfacial interaction in the PLA/HA composite can be significantly improved. The diametral tensile strength of PLA/HA composite prepared from PLA-grafted HA was found to be over twice that of the composite prepared from the non-modified HA. Moreover, the tensile strength of the improved composite was 23 % higher than that of PLA alone. By varying additional variables, this approach has the potential to produce bioresorbable composites with improved mechanical properties that are in the range of natural bones, and can have wide applications for bone fixation and repair in load-bearing areas.     

热致液晶共聚酯/PA6/RSMA原位复合材料2.力学性质与破坏行为

选用Vectra A950热致液晶共聚酯（LCP）制备热致液晶共聚酯（LCP）/聚酰胺6（PA6）/苯乙烯-马来酸酐无规共聚物（RSMA）三元共混物。并注射成型制得复合板材。研究三元LCP/PA6/RSMA原位复合材料的形态结构、力学性质和破坏行为。结果表明,PSMA是LCP/PA6复合材料的有效增容剂。RSMA的加入有利于LCP在PA6基体中原位成纤,增强了两相之间的界面粘接。加入RSMA后,LCP/PA6原位复合材料的杨氏模量、抗拉强度和抗冲击强度明显提高。RSMA能延长LCP/PA6复合材料的裂纹引发时间、增加裂纹引发能和总冲击能。对LCP/PA6原位复合材料有增韧作用。RSMA的加入量存在一临界值。     

粉末冶金法制备Ti/HA生物复合材料的体内生物活性

采用粉末冶金法制备了Ti/HA复合材料,对其体内生物活性进行了研究。植入早期,纯Ti种植体周围有一层纤维组织形成,纤维膜随着种植时间的延长逐渐消失,并伴随有新骨形成,植入6个月后,纯Ti与周围骨组织之间形成典型的骨接触界面。含钛量为30％的复合材料周围在植入早期有很薄一层新骨形成,种植体与周围骨组织之间存在很大的空隙,含钛量为50％和70％的复合材料周围则有大量的新骨形成,植入6个月后三种复合材料均与周围骨组织之间形成了牢固的骨性结合界面。可见,三种Ti/HA复合材料均具有良好的生物活性。但含钛量为30％的复合材料成骨速度明显低于另两种复合材料。三种Ti/HA复合材料的生物活性均大于纯Ti。     

Synthesis of aligned porous poly(ε-caprolactone) (PCL)/hydroxyapatite (HA) composite microspheres

We synthesized poly(ε-caprolactone) (PCL)/hydroxyapatite (HA) composite microspheres with an aligned porous structure and evaluated their potential applications in bone tissue engineering. A range of HA particles (0, 5, 10 and 20 wt.% in relation to the PCL polymer) were added to a PCL solution in order to improve the biocompatibility of the porous PCL/HA composite microspheres. All the synthesized microspheres showed that the HA particles were distributed well in the PCL matrix, while preserving their aligned porous structure. The average size of the PCL/HA composite microspheres increased from 62 ± 7 to 179 ± 95 μm with increasing HA content from 0 to 20 wt.%. The incorporation of the HA particles to the PCL polymer led to a considerable improvement in in vitro bioactivity, which was assessed by immersing the PCL/HA composite microspheres in simulated body fluid (SBF). A number of apatite crystals could be precipitated on the surface of the aligned porous PCL/HA composite microspheres after soaking in the SBF for 7 days.     

Multichannel mould processing of 3D structures from microporous coralline hydroxyapatite granules and chitosan support materials for guided tissue regeneration/engineering

A three-dimensional composite material was produced from microporous coralline origin hydroxyapatite (HA) microgranules, chitosan fibers and chitosan membrane. Cylindrical HA microgranules were oriented along channel direction within multichannel mould space and aligned particles were supported with fibers and a chitosan membrane. The positive replica of mould channels was clasp fixed to produce thicker scaffolds. Light microphotographs of the developed complex structure showed good adhesion between the HA particles, the fibers and the supporting membrane. The composite material showed 88% (w/w) swelling in one hour and preserved the complex structure of the original material upon long-term incubation in physiological medium. MEM extract test of HA chitosan complex showed no cell growth inhibition and cell viability assay (MTS) indicated over 90% cell viability.