复合抗肿瘤珊瑚羟基磷灰石人工骨的体内成骨

背景：复合抗肿瘤珊瑚羟基磷灰石人工骨在体内外有良好的缓释效果及抗肿瘤作用,但由于其所复合药物量较大,植入体内骨缺损处较高的局部药物浓度是否影响骨的正常诱导、传导及生长？ 目的：建立复合抗肿瘤珊瑚羟基磷灰石人工骨成骨模型,进一步分析复合抗肿瘤珊瑚羟基磷灰石人工骨的体内成骨效应及规律。 方法：分别将珊瑚羟基磷灰石人工骨及复合抗肿瘤珊瑚羟基磷灰石人工骨植入兔股骨两干骺端骨缺损模型,定期观察股骨X射线影像,并取材行组织病理切片,观察材料降解和被新骨替代的速度、骨与材料界面的结合情况,材料内部新骨生长情况。 结果与结论：珊瑚羟基磷灰石人工骨植入后与周围骨形成组织及骨桥连接较复合抗肿瘤珊瑚羟基磷灰石人工骨快,植入4周后X射线片影像及组织切片示珊瑚羟基磷灰石人工骨边缘开始逐渐不清,并逐步与动物骨形成骨愈合。复合抗肿瘤珊瑚羟基磷灰石人工骨植入后早期8周内局部以抑制组织细胞生长为主,6~12周逐渐有组织结构向材料孔隙内生长且逐渐出现成骨细胞、骨基质及骨细胞,新生骨逐渐生长替代融合,26周左右与周围骨形成骨愈合。说明复合抗肿瘤珊瑚羟基磷灰石人工骨植入早期虽对骨愈合有一定的抑制作用,但最终仍可自行与周围骨缺损达到骨愈合。     

纳米羟基磷灰石纤维蛋白凝胶复合重组人成骨蛋白1修复骨缺损

背景：纳米级的羟基磷灰石纤维蛋白凝胶材料与人体内组织成分更为相似,具有良好的生物与力学性能,但缺乏骨诱导作用。 目的：观察纳米羟基磷灰石纤维蛋白凝胶/重组人成骨蛋白1复合人工骨的骨缺损修复能力。 方法：制备新西兰大白兔单侧桡骨缺损模型后,以数字表法随机分为3组,分别植入不同材料行骨缺损修复：纳米羟基磷灰石纤维蛋白凝胶/重组人成骨蛋白1人工骨组、纳米羟基磷灰石/纤维蛋白凝胶组、空白对照组(未植入任何材料)。术后4,8,12周行大体标本观察、X射线、扫描电镜、放射性核素骨扫描及生物力学测试,比较各组材料修复骨缺损的能力。 结果与结论：术后4,8,12周,纳米羟基磷灰石纤维蛋白凝胶/重组人成骨蛋白1人工骨组X射线评分、成骨效果、放射性核素聚集强度、生物力学强度均高于纳米羟基磷灰石/纤维蛋白凝胶组(P < 0.05)。空白对照组骨缺损区无骨性连接,骨端硬化,骨缺损未能修复。说明纳米羟基磷灰石纤维蛋白凝胶/重组人成骨蛋白1复合人工骨具有良好的骨缺损修复能力,有望成为一种理想的骨缺损修复材料。     

两种人工合成骨形态发生蛋白活性多肽的骨诱导能力

背景：根据骨形态发生蛋白氨基酸序列中诱导成骨的核心功能区,课题组采用人工固态合成法合成了骨形态发生蛋白活性多肽Ⅰ与骨形态发生蛋白活性多肽Ⅱ。 目的：初步评价骨形态发生蛋白多肽Ⅰ和骨形态发生蛋白活性多肽Ⅱ在动物体内的骨诱导能力。 方法：将42只SD大鼠随机均分为7组,分别在臀部肌肉内植入载0.2,0.4,0.8 g/L骨形态发生蛋白多肽Ⅰ的羟基磷灰石/聚乳酸材料、载0.2,0.4,0.8 g/L骨形态发生蛋白多肽Ⅱ的羟基磷灰石/聚乳酸材料及羟基磷灰石/聚乳酸材料。植入后3,5周进行X射线、CT及组织学检测,观察7组成骨情况。 结果与结论：载骨形态发生蛋白多肽羟基磷灰石/聚乳酸材料植入后3,5周的局部成骨均高于羟基磷灰石/聚乳酸材料组,说明两种多肽均具有一定的诱导成骨能力,且随着时间的增长效果更强;植入5周后,载0.4,0.8 g/L骨形态发生蛋白多肽Ⅰ组成骨效果高于载0.2 g/L骨形态发生蛋白多肽Ⅰ组、载0.2,0.4,0.8 g/L骨形态发生蛋白多肽Ⅱ组(P < 0.05);载0.4 g/L骨形态发生蛋白多肽Ⅰ组与载0.8 g/L骨形态发生蛋白多肽Ⅰ组成骨效果无差异,表明骨形态发生蛋白多肽Ⅰ的诱导成骨能力强于骨形态发生蛋白多肽Ⅱ。     

纳米双相陶瓷人工骨的成骨及降解

背景：烧结后的纳米羟基磷灰石结晶度很高,在体内很难降解;纳米β-磷酸三钙的降解速度太快,不利于体内生物组织在材料上附着,不利于引导成骨。 目的：观察纳米羟基磷灰石/纳米β-磷酸三钙双相陶瓷人工骨的成骨及降解性能。 方法：将36只青紫蓝兔随机分为实验组、对照组及空白组,制作左侧挠骨缺损模型,实验组与对照组分别植入纳米羟基磷灰石/纳米β-磷酸三钙双相陶瓷人工骨、纳米羟基磷灰石人工骨,空白组不植入任何材料。术后4,8,12周观察成骨和材料降解情况。 结果与结论：①术后12周时X射线：实验组可见材料基本降解,连续性骨痂通过骨缺损部位。对照组材料未见明显降解,骨缺损处有骨痂修复。空白组骨缺损未见修复。②术后12周时组织学观察：实验组材料孔隙内以骨细胞和成骨细胞为主,有少量软骨细胞,出现散乱的骨松质,材料完全降解。对照组材料孔隙内以骨细胞为主,有少量成骨细胞和软骨细胞,材料未见明显降解。空白组可见纤维结缔组织及胶原纤维。③术后12周时扫描电镜观察：实验组材料降解,骨缺损部位被新生骨松质取代。对照组材料未见降解,骨缺损部位大都被新生骨松质取代。空白组无明显骨重建。表明纳米羟基磷灰石/纳米β-磷酸三钙双相陶瓷人工骨具有良好成骨能力及降解性能。     

硫酸钙/羟基磷灰石可注射性骨替代物凝固时间的影响因素

目的分析可注射性硫酸钙/羟基磷灰石骨替代物凝固时间的影响因素。方法分别在改变凝固条件后,或改变羟基磷灰石含量,液固比,固化液成分后用 Gillmore 双针法测定硫酸钙/羟基磷灰石骨替代物凝固时间的变化。结果当减低液固比,提高羟基磷灰石含量或升高温度时可注射性硫酸钙／羟基磷灰石骨替代物凝固时间缩短,使用固化液欧乃派克或蒸馏水对其凝固时间的影响无显著性差异。结论硫酸钙/羟基磷灰石骨替代物的凝固时间通过改变影响因素可以达到临床操作的要求。     

纳米银与纳米羟基磷灰石混合填塞对即刻种植骨结合的作用

背景：纳米银具有显著的抗菌性能,纳米羟基磷灰石具有良好的生物活性及机械强度,将两者混合既可促进骨形成又具有抗菌性能。 目的：观察纳米银与纳米羟基磷灰石混合填塞在即刻种植骨结合过程中的作用。 方法：拔除9只新西兰大白兔上下颌4个切牙后,随机分为实验组(n=6)与对照组(n=3),实验组在拔牙窝内填塞纳米银与纳米羟基磷灰石混合物,对照组在拔牙窝内填塞纳米羟基磷灰石,两组均即刻植入钛螺纹钉。植入后4,8,12周取完整上下颌骨标本,进行大体观察、扭矩实验测试、X射线骨密度分析及组织学观察。 结果与结论：实验组不同时间点的新生骨灰度值、最大扭矩值均高于对照组(P < 0.05)。植入12周内,实验组成骨速度及新生骨组织成熟度均高于对照组,且始终无炎细胞浸润;对照组植入4周时可见大量炎细胞浸润,植入8周时仍可见少量炎细胞。表明纳米银与纳米羟基磷灰石混合植骨有更好的抗菌作用、生物相容性和骨诱导能力,能够加快骨结合,促进成骨,较单纯使用纳米羟基磷灰石效果好。 中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

多孔碳酸化羟基磷灰石水泥植入修复兔包容性骨缺损的力学分析

背景:采用发泡剂成孔技术,制成了有知识产权的新型骨修复材料多孔碳酸化羟基磷灰石,既保留了碳酸化羟基磷灰石骨水泥原位固化性能等所有的优点,同时又形成多孔结构。目的:通过动物实验观察新型的骨修复材料多孔碳酸化羟基磷灰石水泥修复骨缺损的力学效果。方法:30只新西兰大白兔,手术组25只在双侧股骨髁制备直径为5.5mm、深12mm的骨缺损动物模型,左侧植入多孔碳酸化羟基磷灰石骨水泥为实验组,右侧植入碳酸化羟基磷灰石骨水泥为对照组。非手术组5只,用于正常力学对照。将多孔碳酸化羟基磷灰石骨水泥和碳酸化羟基磷灰石骨水泥试件经模仿体液浸泡,检测力学强度。同时在手术组背肌内分别植入多孔碳酸化羟基磷灰石骨水泥和碳酸化羟基磷灰石骨水泥标准试件。分别于术后2,4,8,12,16周分批处死动物,进行试件骨内和肌内植入的力学实验分析和试件在模仿体液中浸泡后的抗压强度测试。结果与结论:多孔碳酸化羟基磷灰石骨水泥:2周时的骨内力学强度较低,4周时降到最低,8周时接近正常松质骨强度,12周时超过正常松质骨强度,16周时恢复到正常松质骨水平。碳酸化羟基磷灰石骨水泥:2周时骨内植入强度较多孔碳酸化羟基磷灰石骨水泥略高,4周时有所降低,8,12,16周时略升高,但是始终低于正常松质骨的强度。多孔碳酸化羟基磷灰石骨水泥和碳酸化羟基磷灰石骨水泥在SBF中浸泡的抗压强度变化不大。试件植入肌内后抗压强度变化非常显著。结果表明,多孔碳酸化羟基磷灰石水泥具有原位固化性能和一定的力学支撑作用,能作为自体骨移植的一种替代物修复骨缺损。     

纳米羟基磷灰石仿生骨材料的研究进展

纳米羟基磷灰石仿生骨材料因其与天然骨结构和成分相近,已成为组织工程领域研究的热点之一。介绍了纳米羟基磷灰石的各种制备方法及其复合材料的合成方法,并对纳米羟基磷灰石复合材料的特性进行了说明。通过将纳米羟基磷灰石表面修饰改性后,其复合材料有着广阔的应用前景,可用于修复骨缺损,也可以作为药物载体治疗肿瘤。对近年来纳米羟基磷灰石仿生骨材料的研究进展进行了综述。     

载银珊瑚羟基磷灰石人工骨的机械性能及修复桡骨大段污染性骨缺损

背景：国内外学者在抗菌骨移植材料的基础实验和临床实践方面进行了大量的研究,取得了一定的进展。目的：通过体外力学实验检测抗菌性载银珊瑚羟基磷灰石人工骨的机械性能,并通过动物实验检测其修复大段污染性骨缺损的能力。方法：利用压缩试验及三点弯曲试验评价载银珊瑚羟基磷灰石、珊瑚羟基磷灰石与珊瑚的力学性能。将36只新西兰大白兔随机分为4组,均制作右侧大段污染性桡骨缺损模型,其中3组分别植入载银珊瑚羟基磷灰石、珊瑚羟基磷灰石与原位自体骨,另1组不植入任何材料(对照)。术后2,6,10周处死动物并取材,通过大体观察、影像学检查、组织学检查观察比较各组骨缺损修复情况,通过细菌学检查评估各组抗菌情况。结果与结论：载银珊瑚羟基磷灰石、珊瑚羟基磷灰石与珊瑚的力学性能无差异。术后10周时,X射线及组织学观察结果显示,载银珊瑚羟基磷灰石骨缺损内为成熟的骨组织,骨组织中有大量的骨陷窝和成熟的骨细胞,可见哈弗氏系统,材料大部分降解,只有少量残留,骨髓腔有部分再通,骨缺损修复效果与自体骨组相似,优于珊瑚羟基磷灰石组与对照组。细菌学检查显示载银珊瑚羟基磷灰石具有良好的抗菌能力。表明载银珊瑚羟基磷灰石具有较好的力学性能及抗菌性能,可用于修复大段污染性骨缺损。 中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

纳米人工骨在颈前路植骨融合中的应用

背景：纳米羟基磷灰石/聚酰胺人工骨具有良好的生物相容性与较强的组织结合力,在恢复神经功能方面具有显著作用。目的：探讨颈前路植骨融合中应用纳米羟基磷灰石/聚酰胺人工骨代替自体髂骨治疗的临床效果。方法：采用随机数字表法将96例颈椎病和颈椎创伤脱位患者均分为观察组和对照组,两组患者均进行颈前路植骨融合治疗,观察组植入纳米羟基磷灰石/聚酰胺人工骨,对照组植入自体髂骨。比较两组手术情况、植入后不同时间随访的日本骨科协会(JOA)脊髓功能评分、椎体高度丢失及植骨融合率。结果与结论：两组手术时间、术后下床活动时间、术后住院时间比较差异无显著性意义(P > 0.05),观察组术中出血量显著低于对照组(P < 0.05)。两组随访3,6个月及末次随访的JOA评分均高于治疗前(P < 0.05),但两组间不同时间点JOA评分比较差异无显著性意义(P > 0.05);两组随访6个月及末次随访的椎体高度丢失程度、植骨融合率比较差异均无显著性意义(P > 0.05);两组均未发生与植骨材料相关的不良反应。表明颈前路植骨融合中应用纳米羟基磷灰石/聚酰胺人工骨具有与自体髂骨相当的临床效果。中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

Freeze casting of hydroxyapatite scaffolds for bone tissue engineering

Although extensive efforts have been put into the development of porous scaffolds for bone regeneration, with encouraging results, all porous materials have a common limitation: the inherent lack of strength associated with porosity. Hence, the development of porous hydroxyapatite scaffolds has been hindered to non-load bearing applications. We report here how freeze casting can be applied to synthesize porous scaffolds exhibiting unusually high compressive strength, e.g. up to 145 MPa for 47% porosity and 65 MPa for 56% porosity. The materials are characterized by well-defined pore connectivity along with directional and completely open porosity. Various parameters affecting the porosity and compressive strength have been investigated, including initial slurry concentration, freezing rate, and sintering conditions. The implications and potential application as bone substitute are discussed. These results might open the way for hydroxyapatite-based materials designed for load-bearing applications. The biological response of these materials is yet to be tested.     

Silk as a biocohesive sacrificial binder in the fabrication of hydroxyapatite load bearing scaffolds

Limitations of current clinical methods for bone repair continue to fuel the demand for a high strength, bioactive bone replacement material. Recent attempts to produce porous scaffolds for bone regeneration have been limited by the intrinsic weakness associated with high porosity materials. In this study, ceramic scaffold fabrication techniques for potential use in load-bearing bone repairs have been developed using naturally derived silk from Bombyx mori. Silk was first employed for ceramic grain consolidation during green body formation, and later as a sacrificial polymer to impart porosity during sintering. These techniques allowed preparation of hydroxyapatite (HA) scaffolds that exhibited a wide range of mechanical and porosity profiles, with some displaying unusually high compressive strength up to 152.4 ± 9.1 MPa. Results showed that the scaffolds exhibited a wide range of compressive strengths and moduli (8.7 ± 2.7 MPa to 152.4 ± 9.1 MPa and 0.3 ± 0.1 GPa to 8.6 ± 0.3 GPa) with total porosities of up to 62.9 ± 2.7% depending on the parameters used for fabrication. Moreover, HA-silk scaffolds could be molded into large, complex shapes, and further machined post-sinter to generate specific three-dimensional geometries. Scaffolds supported bone marrow-derived mesenchymal stem cell attachment and proliferation, with no signs of cytotoxicity. Therefore, silk-fabricated HA scaffolds show promise for load bearing bone repair and regeneration needs.     

High strength, low stiffness, porous NiTi with superelastic properties

Near-stoichiometric NiTi with up to 18% closed porosity was produced by expansion at 1200 °C of argon-filled pores trapped by powder metallurgy within a NiTi billet. When optimally heat-treated, NiTi with 6–16% porosity exhibits superelasticity, with recoverable compressive strains up to 6% at a maximum compressive stress up to 1700 MPa. The apparent Young’s modulus of NiTi with 16% porosity, measured during uniaxial compression, is in the range of 15–25 GPa (similar to human bone), but is much lower than measured ultrasonically (40 GPa), or predicted from continuum elastic mechanics. This effect is attributed to the reversible stress-induced transformation contributing to the linear elastic deformation of porous NiTi. The unique combination of low stiffness, high strength, high recoverable strains and large energy absorption of porous superelastic NiTi, together with the known biocompatibility of NiTi, makes this material attractive for bone–implant applications.     

Effects of bone ingrowth on the strength and non-invasive assessment of a coralline hydroxyapatite material

The dependence of strength on the amount of bone growth into a hydroxyapatite material made from coral was investigated. Block and granular forms of the material were implanted into cortical and trabecular regions of the skeletons of 16 dogs. The results were examined after 4, 8, 12 and 16 wk, with four dogs in each experimental group. When implanted into cortical bone, the bending strength of the implant material was found to be highly correlated with the amount of pore space which had become occupied by bone (r = 0.92, P less than 0.005 for the block form; r = 0.84, P less than 0.005 for the granular form). Multiple regression analysis showed that six histomorphometric measures of ingrowth accounted for 96% of the variability in bending strength of the block material, and there were no significant differences between block and granular forms of the material. On the other hand, when implanted into trabecular bone, the block form of the material achieved greater compressive strength than the granular form. While both strength and ingrowth increased with time, there were poor correlations between these two variables. Finally, when the material is implanted into trabecular bone, it becomes stronger in compression than the surrounding bone; when implanted in cortical bone, linear modelling suggests that resorption and replacement of the implant would be required to approximate the bending strength of the surrounding bone.     

Prostaglandin E1 and recombinant bone morphogenetic protein effect on strength of hydroxyapatite implants.

Although combinations of hydroxyapatite (HAP) and bone morphogenetic protein (BMP) are expected to provide potent alternatives to autogenous bone grafts, it is still anticipated that substances that act synergistically with BMP will be found because the inducing potential of purified BMP in bone is not strong enough. We already have shown that prostaglandin (PG) E1 has a strong and dose-dependent synergistic effect on the osteoinductive activity induced by recombinant human (rh) BMP and that it enhances osteoconduction even when used alone. In this study, porous HAP rods were treated as follows: (1) without PGE1 or rhBMP (control group); (2) with varying concentrations of PGE1; and (3) with varying concentrations of PGE1 combined with 1 microg of rhBMP-2. The rods were subperiosteally implanted on the cranial bone of rabbits to evaluate the effect of these treatments on the mechanical strength of the implanted HAP rods. The HAP rods were removed 3, 6, or 9 weeks after implantation and subjected to mechanical strength determinations. The control group (no addition of BMP to the rods) showed no significant increase in three-point bending strength or in compression strength compared to pre-implantation. On the other hand, PGE1 combined with rhBMP had a strong and dose-dependent effect on the mechanical strength of HAP, increasing it significantly, especially compression strength. PGE1 also increased mechanical strength even when used alone. Histological examination revealed that PGE1, whether or not it was combined with rhBMP, increased bone formation into the pores of HAP and consequently increased the mechanical strength of porous HAP.     

Mechanical and in vivo performance of hydroxyapatite implants with controlled architectures.

Internal architecture has a direct impact on the mechanical and biological behaviors of porous hydroxyapatite (HA) implant. However, traditional processing methods provide minimal control in this regard. To address the issue, we developed a new processing method combining image-based design and solid free-form fabrication. We have previously published the processing method showing fabricated HA implants and their chemical properties. This study characterized the mechanical and the in vivo performance of designed HA implants. Thirteen HA implants with orthogonal channels at 40% porosity were tested on an Instron machine. The compressive strength and compressive modulus measured were 30+/-8 MPa and 1.4+/-0.4 GPa, comparable to coralline porous HA. Twenty-four cylindrical HA implants with two architecture designs, orthogonal and radial channels, were implanted in the mandibles of four Yucatan minipigs for 5 and 9 weeks. Normal bone regeneration occurred in both groups. At 9 weeks, bone penetrated 1.4mm into both scaffold designs. The percent bone ingrowth in the penetration zone was higher in the orthogonal channel design but not statistically different due to the low number of samples. However, the overall shape of the regenerated bone tissue was significantly different. In the orthogonal design, bone and HA formed an interpenetrating matrix, while in the radial design, the regenerated bone formed an intact piece at the center of the implant. These preliminary results showed that controlling the overall geometry of the regenerated bone tissue is possible through the internal architectural design of the scaffolds.     

In vivo evaluation of a novel porous hydroxyapatite to sustain osteogenesis of transplanted bone marrow-derived osteoblastic cells

Biosynthetic bone grafts are considered to contain one or more of three critical components: osteoprogenitor cells, an osteoconductive matrix, and osteoinductive growth factors. The basic requirements of the scaffold material are biocompatibility, mechanical integrity, and osteoconductivity. A major design problem is satisfying these requirements with a single composite. In this study, we hypothesize that one composite that combines bone marrow-derived osteoblasts and a novel mechanical reinforced porous hydroxyapatite with good biocompatibility and osteoconductivity (HA/BMO) can reach these requirements. A novel sintered porous hydroxyapatite (HA) was prepared by the following procedures. The HA slurry was foamed by adding polyoxyethylenelaurylether (PEI) and mixing. The pores were fixed by crosslinking PEI with diepoxy compounds and the HA porous body was sintered at 1200 degrees C for 3 h. The HA sintered porous body had a high porosity (77%), and was completely interconnected. Average pore diameter was 500 microm and the interconnecting path 200 microm in diameter. The compressive (17 MPa) and three-point bending (7 MPa) strengths were high. For in vivo testing, the 2-week subcultured HA/BMO (+) composites were implanted into subcutaneous sites of syngeneic rats until 8 weeks after implantation. These implants were harvested at different time points and prepared for the biochemical analysis of alkaline phosphatase activity (ALP) and bone osteocalcin content (OCN), and histological analysis. ALP and OCN in the HA/BMO group were much higher than those in the HA without BMOs control group 1 week after implantation (p < 0.001). Light microscopy revealed mature bone formation in the HA/BMO composite 4 weeks after implantation. In the SEM study, mineralized collagenous extracellular matrix was noted in HA/BMO composite 2 weeks after implantation with numbers of active osteoblasts. We conclude that the composite of the novel HA and cultured BMOs has osteogenic ability in vivo. These results provide a basis for further studies on the use of this composite as an implant in orthopaedic surgery.     

Influence of mixing techniques on the physical properties of acrylic bone cement

Palacos R bone cement was prepared using three commercially available mixing techniques, first generation, second generation and third generation, to determine the mechanical properties and porosity contents of the bone cement. The compressive strengths, bending strengths and flexural moduli were expressed as a function of void content. The volume of pores within the cement structure was found to be a contributing factor to the physical properties of acrylic bone cement. The lower the volume of voids in the cement the better the compressive and flexural properties, hence stronger bone cement. It was found that the best results were obtained from cement that had been mixed using the Mitab Optivac or Summit HiVac Syringe systems at a reduced pressure level of between -72 and -86 kPa below atmospheric pressure, resulting in cement of porosity 1.44-3.17%; compressive strength 74-81 MPa; flexural modulus 2.54-2.60 GPa; and flexural strength 65-73 MPa.     

新型羟基磷灰石多孔支架的制备与性状

背景：目前几种钙羟磷灰石作为骨的替代品已经在临床上使用,但是由于缺少内部交互的连通孔,使得骨形成过程中经常发生病理性的骨折。 目的：采用改良的技术制备互联多孔羟磷灰石陶瓷支架材料,并对其物理化学特征进行检测。 方法：将羟基磷灰石(质量分数60%)与聚乙烯亚胺质量分数40%混合,采用改良的泡沫凝胶技术技术(聚氧乙烯十二烷基醚质量分数1%)制备多孔羟磷灰石陶瓷。扫面电镜检测材料内部结构,将制备的材料移植动物体骨缺损区观察成骨情况。 结果与结论：多孔羟磷灰石陶瓷具有三维结构,内部充满大小较均一的球形孔隙,直径平均为150 μm,孔隙率75%,孔隙上充满窗孔样相互交通的小洞,平均40 μm, 具有足够的抗压度(10~12 MPa)。动物实验表明,多孔羟磷灰石陶瓷表现出较好的成骨诱导性,可见孔隙里形成了新生骨。结果提示改良的羟基磷灰石支架能够在骨组织工程上应用,有望成为新型的改良品。     

Preparation of porous hydroxyapatite scaffolds by combination of the gel-casting and polymer sponge methods

A new technique of combining the gel-casting and polymer sponge methods is introduced in this study to prepare macroporous hydroxyapatite scaffolds, which provides a better control over the microstructures of scaffolds and enhances their mechanical properties. With this technique, we were able to produce scaffolds with mechanical and structural properties that cannot be attained by either the polymer sponge or gel-casting method. The scaffolds prepared have an open, uniform and interconnected porous structure with a pore size of 200-400 microm. A compressive yield strength of approximately 5 MPa equivalent to that of cancellous bone and a compressive modulus of approximately 8 GPa similar to that of cortical bone were achieved. The pore morphology, size, and distribution of the scaffolds were characterized using a scanning electron microscope. X-ray diffraction and Fourier transform infrared spectroscopy were used to determine the crystal structure and chemical composition of scaffolds, respectively. Scaffolds with desired porosity, pore size, and geometry can be prepared by using polymer sponges of appropriate structures.