HA/PDLLA复合材料体内引导成骨过程的组织学研究

为获得羟基磷灰石（HA）／外消旋聚乳酸（PDLLA）复合材料体内引导成骨的实验依据，采用HA／PDLLA复合材料和纯PDLLA材料对照组进行骨内植入实验，通过X线和组织学观察，从组织学角度研究了HA／PDLLA复合材料在体内引导成骨的过程和实际愈合效果，并探讨了成骨机制。体内植入实验的组织学观察结果表明HA／PDLLA复合材料具有良好的生物相容性、适度的生物降解性能、一定的生物学活性和骨传导性能。HA／PDLLA复合材料植入机体后，体内的无菌性炎症轻微，新骨形成速率高于纯PDLLA材料。HA微粒的存在可提高复合材料的机械性能，避免材料过早丧失力学强度。     

新型骨修复材料PDLLA/HA/DBM的生物相容性

评价用悬浮液分散共混合法制备的新型骨修复材料PDLLA／HA／DBM的生物相容性。按照我国卫生部《生物材料和医疗器材生物学评价的技术要求》中的标准，对PDLLA／HA／DBM进行急性毒性实验、热原实验、溶血实验、兔肌肉内种植实验和PET实验。结果表明，PDLLA／HA／DBM无毒性，无热原性，不引起溶血反应，植入兔肌肉后逐渐发生降解并被软骨组织和骨组织取代，不引起全身和局部葡萄糖代谢改变。新型骨修复材料PDLLA／HA／DBM具有良好的生物相容性。     

消旋聚乳酸/ 羟基磷灰石复合材料成骨性的体内实验研究

 目的 探讨消旋聚乳酸/羟基磷灰石（PDLLA/HA）复合材料在动物体内的生物相容性和成骨性。 方法 将 66 只日本大耳兔随机为 3 组，每组 22 只。其中 2 组分别于股骨髁间植入 PDLLA/HA 复合材料圆柱棒（PDLLA/HA 组）和 PDLLA 圆柱棒（PDLLA 组），1 组仅手术而不植入材料作为对照组。术后 3、6 周植入部位摄 X 线片观察植入材料的变化及其与周围组织的结合情况；术后 3、6、12、24 周每组各处死 5 只兔，进行植入部位大体解剖学观察和组织病理学观察。 结果 术后 X 线观察显示 PDLLA/HA 组植入材料显影良好，与周围组织有明显界限；而 PDLLA 组可以看到明显的孔道。大体解剖学和组织病理学观察显示 PDLLA/HA 组术后早期局部炎症反应明显轻于 PDLLA 组，材料与周围组织结合紧密，膜外有少许新骨生成；6 周时膜外新骨增多；12 周时复合螺钉周围有少量新生骨小梁形成，边缘附有大量的成骨细胞；24 周时可见纤维组织长入材料，材料色、形、质与周围结缔组织相近。而 PDLLA 组材料降解明显，12 周后已不能维持棒体形状。 结论 PDLLA/HA 复合材料具有良好的生物相容性和体内成骨性。     

HA/PDLLA复合材料体内植入的组织学观察

可吸收骨折内固定材料要求具有较高的初始强度及良好的生物相容性。对自行研制的可吸收羟基磷灰石/聚DL-乳酸(HA/PDLLA)复合骨折内固定材料进行骨内植入实验。大体观察结果表明:HA/PDLLA 材料强度良好,周围无明显的炎性反应。结论:HA/PDLLA复合材料强度较好,适用于松质骨骨折的固定, 且生物相容性良好。     

聚DL-乳酸/羟基磷灰石复合材料修复长骨缺损的实验研究

目的 :评价羟基磷灰石 (HA)复合聚DL 乳酸 (PDLLA )制备的材料体内成骨能力。方法 :将PDLLA和PDLLA/HA( 2 0wt % )材料采用盐结晶颗粒沥滤法制成三维多孔材料 ,45例 1cm兔桡骨去骨膜缺损分为三组 ,分别植入 2种材料和作空白对照 ,术后 2 ,4,8,12周行X线、组织学及扫描电镜观察骨生成状况 ,8、12周行生物力学测试 (三点折弯强度 )。结果 :泡沫状PDLLA/HA ( 2 0wt % )材料比纯PDLLA成骨更好 (P <0 .0 5 ) ,实验组与对照组相比差异有显著性 (P <0 .0 5 )。结论 :PDLLA具有良好的生物相容性 ,制成多孔状具有较好的骨传导性能 ,HA( 2 0wt % )的加入促进了多孔PDLLA的骨传导能力 ,提高了骨生成的质量。PDLLA/HA( 2 0wt % )复合材料是一种有临床应用前景的骨移植材料。     

聚乳酸及其复合材料在骨组织工程方面的研究进展

聚乳酸（PLA）是具有良好的生物相容性和生物降解特性的聚合物,是FDA认可的一类可植入体内的生物材料。本文综述了PLA、羟基磷灰石（HA）／PLA复合材料及生物活性有机成分／PLA复合材料在骨组织工程中应用的研究进展。     

HA-40vo1％Ti复合材料与动物骨组织相容性体内研究

采用热压烧结法制备HA-40vol％Ti复合材料，并通过体内植入试验，研究了该复合材料的生物相容性。结果表明，HA-40vol.％Ti复合材料具有良好的生物相容性和骨引导性，可以与骨发生骨整合，早期骨整合和骨引导性优于纯Ti。在整个植入时间段内，HA-40vol．％Ti复合材料与周围骨组织的结合强度均比纯钛的高，且增长的快。植入3月后，复合材料与新骨的结合强度已达到4．73MPa。     

HA-40vol%Ti复合材料与动物骨组织相容性体内研究

采用热压烧结法制备HA-40vol%Ti复合材料,并通过体内植入试验,研究了该复合材料的生物相容性.结果表明,HA-40vol.%Ti复合材料具有良好的生物相容性和骨引导性,可以与骨发生骨整合,早期骨整合和骨引导性优于纯Ti.在整个植入时间段内,HA-40vol.%Ti复合材料与周围骨组织的结合强度均比纯钛的高,且增长的快.植入3月后,复合材料与新骨的结合强度已达到4.73MPa.     

可吸收羟基磷灰石/聚DL-乳酸骨折内固定材料机械强度和生物降解性研究

目的评价自行研制的可吸收羟基磷灰石/聚DL-乳酸(HA/PDLLA)复合骨折内固定材料的机械强度和生物降解性。方法体外降解实验是把相同分子量的HA/PDLLA和单纯PDLLA试件分别置于PBS缓冲液中,于2、4、6、8、10、12周取材,测试生物降解率、吸水率、失重率、机械强度及降解液pH值,并作扫描电镜(SEM)观察;体内实验是用一枚HA/PDLLA棒内固定兔股骨髁松质骨部横形截骨,作X线摄片、组织学、机械强度及材料骨界面SEM观察。结果HA/PDLLA复合材料较单纯PDLLA材料降解速度减慢,机械强度提高,骨折正常愈合。结论HA/PDLLA材料具有足够的强度保证实验性松质骨骨折正常愈合。     

纳米相羟基磷灰石/胶原复合材料研究进展

综述羟基磷灰石(hydroxyapatite,HA)/胶原复合材料的研究进展,着重阐述自组装纳米相羟基磷灰石/胶原复合材料的制作方法、结构特点、体内植入后修复骨缺损的效果及降解过程。基于仿生学设计的纳米相羟基磷灰石/胶原复合材料,其HA纳米晶体约50～100nm,HA的C-轴沿胶原纤维排列,形成片状包绕胶原纤维束,HA和胶原分子之间为牢固的化学键性结合,为自组装的纳米结构,和自然骨中钙化的胶原相同。复合材料体内植入后降解和骨替代的过程与骨的改建过程相似。纳米相羟基磷灰石/胶原复合材料具有生物降解性高、表面能大、生物活性好、生物相容性好等特点,作为骨修复和重建材料具有更好的前景。     

Development and in vitro characterisation of novel bioresorbable and bioactive composite materials based on polylactide foams and Bioglass for tissue engineering applications

Bioactive and bioresorbable composite materials were fabricated using macroporous poly(DL-lactide) (PDLLA) foams coated with and impregnated by bioactive glass (Bioglass) particles. Stable and homogeneous Bioglass coatings on the surface of PDLLA foams as well as infiltration of Bioglass particles throughout the porous network were achieved using a slurry-dipping technique in conjunction with pre-treatment of the foams in ethanol. The quality of the bioactive glass coatings was reproducible in terms of thickness and microstructure. Additionally, electrophoretic deposition was investigated as an alternative method for the fabrication of PDLLA foam/Bioglass composite materials. In vitro studies in simulated body fluid (SBF) were performed to study the formation of hydroxyapatite (HA) on the surface of PDLLA/Bioglass composites. SEM analysis showed that the HA layer thickness rapidly increased with increasing time in SBF. The high bioactivity of the PDLLA foam/Bioglass composites indicates the potential of the materials for use as bioactive, resorbable scaffolds in bone tissue engineering.     

In vivo evaluation of a porous hydroxyapatite/poly-DL-lactide composite for use as a bone substitute

We investigated the biocompatibility, osteoconductivity, and biodegradability of a porous composite of hydroxyapatite (HA) and poly-DL-lactide (PDLLA) implanted into rabbit femoral condyles and compared it with porous HA. Six weeks after implantation, the HA/PDLLA was covered with bone and contacted the bone directly. The amount of newly formed bone in the pores was similar in both materials during the examined period. The newly formed bone in the HA/PDLLA tended to increase over 26 weeks, but that in the HA did not show a significant increase after 12 weeks. By 26 weeks, remodeling of the newly formed bone in the pores was seen and bone marrow tissue was found in the pores of the HA/PDLLA. The porous HA/PDLLA was resorbed much faster than the porous HA. Porous HA/PDLLA was resorbed continuously through bone formation and remodeling. Conversely, porous HA was scarcely resorbed throughout the period. HA/PDLLA is thought to be degraded almost completely after about 1 year, and in this study, porous HA/PDLLA showed excellent osteoconductivity and faster resorption than HA. Therefore, HA/PDLLA might be a desirable material for bone substitutes.     

聚D,L-乳酸/羟基磷灰石复合纤维的力学性能研究

采用熔融纺丝法制备PDLLA／HA复合纤维，探讨PDLLA／HA复合纤维的力学性能及影响因素和性能变化规律。实验结果表明：在分子量为12万的PDLLA中，加入一定量4～20μm的HA颗粒能提高复合纤维的力学性能。在PDLLA基体中添加HA的质量分数以10％为宜，以此配比制备的复合纤维的断裂强度高于其它配比复合纤维的断裂强度。采用分子量为20～30万的PDLLA制备的复合纤维断裂强度高，性能优异。复合纤维断裂强度随纤维直径的增加而下降，在直径为40～60μm时，复合纤维断裂伸长率高，弹性好。     

聚DL-乳酸/磷酸盐复合多孔支架材料的制备及降解性能

采用溶液浇铸 -颗粒滤除法制备了聚 DL-乳酸 (PDL L A) ,聚 DL-乳酸 /羟基磷灰石 (PDL L A/ 2 0 wt%HA)、及聚 DL-乳酸 / β-磷酸三钙 (PDL L A/ 2 0 wt% β- TCP)复合多孔支架材料。研究了支架材料在体外降解中压缩强度、分子量、质量及水解液的 p H值变化规律。结果显示 :复合多孔支架中 HA和 β- TCP均匀分布在 PDL L A基质中 ,复合支架的孔隙率可达 84 % ,磷酸盐微粒的加入对多孔支架的孔隙率有一定的影响 ,但可提高多孔支架的压缩强度 ,并可中和 PDL L A降解所产生的酸性 ,延缓 PDL L A的降解速度。两者相比 ,HA的作用更为明显     

Shape memory properties of poly(D,L-lactide)/hydroxyapatite composites

Poly(D,L-lactide) (PDLLA) and Hydroxyapatite (HA) are compounded, which possess biodegradation, biocompatibility and shape memory properties. In the paper, we prepared serial imposing shape memory composites with different shapes, composite ratios and sample thicknesses. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) were carried out to examine surface morphology, glass transition temperature (Tg), dynamic mechanical properties, and shape memory effect of PDLLA/HA composites, respectively. Moreover, some interesting shape memory behaviors were investigated. The results show that the better disperse morphology of HA grains using the experiment methods, and PDLLA/HA composites at a definite range of compound ratio have much better shape memory effect than pure PDLLA polymer. It indicates that HA particles can improve shape memory effect and PDLLA/HA composites are potential for biomedical applications.     

The effects of a novel-reinforced bone substitute and Colloss®E on bone defect healing in sheep

Hydroxyappatite-β-tricalciumphosphate (HA/β-TCP) was reinforced with poly(D,L)-lactic acid (PDLLA) to overcome its weak mechanical properties. Two substitutes with porosities of 77% and 81% HA/β-TCP reinforced with 12 wt % PDLLA were tested in compression. The effects of allograft, substitute (HA/β-TCP-PDLLA), Colloss?E, and combination of substitute with Colloss?E on bone formation in vivo were evaluated. Cylindrical critical size defects were created at distal femoral condyles bilaterally in sheep. Titanium implant with concentric gap filling with one of the four materials was inserted. After 9 weeks, the sheep were sacrificed. Implants with surrounding bone were harvested and sectioned into two parts: one for microcomputed tomography scanning and push-out test, and one for histomorphometry. The 77% HA/β-TCP reinforced with PDLLA had similar mechanical properties to human cancellous bone and was significantly stronger than the HA/β-TCP without PDLLA. Microarchitecture of gap mass was significantly changed after implantation for all groups. Allograft had stronger shear mechanical properties than the other three groups, whereas there were no significant differences between the other three groups. Significant new bone formation could be seen in vivo in all four groups and there were no significant differences between them. The PDLLA-reinforced substitute seems to be good alternative substitute material for bone healing in sheep. Further investigations should be performed to validate this novel substitute material. ? 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.     

模压挤出条件对聚(D,L-乳酸)及其复合材料力学性能的影响

在辛酸亚锡的催化下由丙交酯开环聚合制备了聚（D，L）-乳酸（PDLLA），并用二苯基甲烷二异氰酸酯（MDI）作为扩链剂分别合成了MDI扩链聚（D，L）-乳酸（PDLLA/MDI）和MDI扩链聚（D，L）-乳酸/羟基磷灰石（PDLLA/HA/MDI）复合材料，采用自行设计的模压挤出设备着重研究了成型加工条件对这两类可生物降解材料力学性能的影响，实验结果表明，在最佳条件下PDLLA和PDLLA/MDI的弯曲强度分别为35.1MPa和51.3MPa，弯曲模量分别为2413.6MPa和1830.9MPa,PDLLA/HA和PDLLA/HA/MDI复合材料的弯曲强度分别为31.2MPa和55.4MPa。弯曲模量分别为1735.0MPa和2068.5MPa，可见，MDI扩链可显著提高PDLLA和PDLLA/HA复合材料的力学性能。