Osteogenesis and Degradation Behavior of rhBMP-27/β-Tricalcium Phosphate Porous Composite Materials

Ultrafine-tricalcium phosphate(β-TCP)powders with good crystalline structure were produced by a new process through bone tissue engineering approach rorous β-TCPcermic was combined with recombined human bone morphogenetic proteins-2(rhBMP-2)to develop a novel composite material ,osteogenesis capacity of the composite was investigated intramuscularly in rat with histological analyses and SEM examination pureβ-TCP porous carmic wsa investigated as the control results show that the compostie materials possess good bilcompatibility biodegradation and strong osteogenesis capacity through inductive process after implantation material degradation began from 2 weeks post-implantation accompanying with the changing o pore structure with the enwrapping and separation fo materials by hyperplatic mesenchymal cells and fibroblast and with the phagocytose reaction of multinucleated giant cells early in 72h immature cartilage could be found within novel composite mature lamellar bone was induced to generate after 3 weeks with strong osteoinduction capacity and controlable bildegradation the novel rhBMP-2\β-TCP porous ceramic is expected to be a promising bone grafting substitute for bone tissue engineering

Microemulsion Synthesis of Mesoporous β-tricalcium Phosphate Powder with a Novel System

The synthesis of mesoporous β-tricalcium phosphate(β-TCP)powder was performed by using the microemulsion approach,with hexadecyltrimethyl ammonium bromide(CTAB)/cyclohexane/n-octyl alcohol microemulsion system.The influences of different pH values and calcination temperatures on the phase composition of the β-TCP powder were studied.The in vitro proliferation of bone marrow mesenchymal stem cells(BMSCs)in the suspensions of β-TCP powders with meso-structure was studied.The phase composition,mesoporous structure,powder morphology,cell morphology and the optical density(OD)were characterized through X-ray diffraction(XRD),field emission scanning electron microscopy(FESEM),Fourier transform infrared(FTIR)spectroscopy,Nadsorption-desorption isotherms,inverted phase contrast microscopy and Multiskan spectrum,respectively.The mesoporous β-TCP powder with specific surface area of 12.85 m^(2)/g and the average pore size 7.11 nm was obtained through the microemulsion approach(100 g/L CTAB/250 mL/L cyclohexane/250 mL/L n-octyl alcohol)with a controlled pH of 7.0,after calcinating the powder at 800℃.It was confirmed that mesoporous β-TCP powder benefits the activity of BMSCs more than the non-mesoporous β-TCP powder.

Comparison between Two Different Manufactured Forms of β-Tricalcium Phosphate Bone Graft in Immediate Implant Placement

Objectives: The aim of this study was to compare the efficacy of using the synthetic β-TCP bone grafting material in two different manufacturing forms (putty and granular) in grafting the jumping zone around immediate implant. Patients and Method: A randomized controlled clinical and radiographic trial was conducted on 24 male patients aged from 45 - 55 with badly decayed non-restorable teeth in the posterior mandibular area and seeking for receiving immediate dental implant directly after extraction. Vertical bone height and bone density were taken at time of implant placement and 6 months postoperatively. Results: The Putty form group and the Granular form group did not differ statistically in terms of age, post-operative complications, or implant outcome six months postoperatively. Additionally, there was a statistically significant increase in Putty form group compared to the Granular form group regarding Marginal bone loss 6 months postoperatively, but there was no statistically significant difference between the Putty form group and the Granular form group regarding Bone density by CBCT. Conclusion: The β-TCP Putty material, compared to β-TCP granular, displayed better surgical handling properties, and both forms had no adverse effect on bone formation, bone tissue maturation or graft volume stability, The β-TCP granular material, compared to β-TCP putty, displayed less marginal bone loss 6 months post-operatively.

Heterotopic bone formation in the musculus latissimus dorsi of sheep usingβ-tricalcium phosphate scaffolds:evaluation of different seeding techniques

Osseous reconstruction of large bone defects remains a challenge in oral and maxillofacial surgery.In addition to autogenous bone grafts,which despite potential donor-site mobility still represent the gold standard in reconstructive surgery,many studies have investigated less invasive alternatives such as in vitro cultivation techniques.This study compared different types of seeding techniques on pureβ-tricalcium phosphate scaffolds in terms of bone formation and ceramic resorption in vivo.Cylindrical scaffolds loaded with autologous cancellous bone,venous blood,bone marrow aspirate concentrate or extracorporeal in vitro cultivated bone marrow stromal cells were cultured in sheep on a perforator vessel of the musculus latissimus dorsi over a 6-month period.Histological and histomorphometric analyses revealed that scaffolds loaded with cancellous bone were superior at promoting heterotopic bone formation and ceramic degradation,with autogenous bone and bone marrow aspirate concentrate inducing in vivo formation of vital bone tissue.These results confirm that autologous bone constitutes the preferred source of osteoinductive and osteogenic material that can reliably induce heterotopic bone formation in vivo.

Osteogenesis Capacity of a Novel BMP/α-TCP Bioactive Composite Bone Cement

To improve the osteogenesis ability of a-tricalcium phosphate (α-TCP) bone cement, a novel BMP/ α-TCP composite bone cement was prepared. By measuring the setting time and compressive strength, the hydration characteristic of bone cement was evaluated. Animal experiments including histological observation, radiographic investigation as well as digital image analyses reveal the difference of osteogenesis ability among BMP,a-TCP bone cement and BMP/α-TCP composite bone cement. Results show that α-TCP bone cement possesses excellent hydration and setting properties as well as high mechanical property. Comparison experiments show that BMP/ α-TCP composite bone cement has a stronger osteogenesis ability. The gross observation of the implant site does not exhibit any inflammation or necrosis. Histological analyses reveal that the material has good osteointegration with host bone, and new bone formation is detected within the materials, which are degrading. Strong osteogenesis ability of the composite is due to not only the excellent osteoconductive potential but also the osteoinductive potential contributed by active BMP releasing and the material degradation. Large skull defect could be well-healed by filling BMP/α-TCP composite bone cement. This novel material proves itself to be an absorbable and bioactive bone cement with an osteogenesis ability. Key words α-tricalcium phosphate (α-TCP) - bone morphogenetic proteins (BMP) - bone cement - osteogenesis - osteoinductivity - bone tissue engineering Funded by 863 Hi-Tech Research and Development Program of China (2002AA326080) and the Fund for Outstanding Young Teacher of the Education Ministry of China(2002123)

Synergistic effects of Mg-substitution and particle size of chicken eggshells on hydrothermal synthesis of biphasic calcium phosphate nanocrystals

Magnesium(Mg^2+))ion plays important roles in biomineralization of bone,teeth and calcium carbonate skeletons.Herein,chicken eggshells mainly comprising of Mg-calcite nanocrystals(Mg/(Mg+Ca)2.0 mol.%)were used to fabricate biphasic calcium phosphate(BCP),a mixture of hydroxyapatite(HA)and p-tricalcium phosphate(p-TCP)nanocrystals,through hydrothermal reactions at 200℃for 24 h.Our results indicated thatβ-TCP nanocrystals formed through the ion-exchange reactions of Mg-calcite,while HA nanocrystals were mainly produced by dissolution-reprecipitation reactions on the surfaces of eggshell samples in the hydrothermal system.Mg substitution in calcite resulted in formation ofβ-TCP nanocrystals instead of HA crystals through ion-exchange reactions.BCP samples with different compositions(28.6-77.8 wt.%β-TCP)were produced by controlling particle sizes of eggshells for hydrothermal reactions.The larger particles lead to the larger proportion ofβ-TCP in the BCP composition.Therefore,Mg substitution and particle size had synergetic effects on the hydrothermal synthesis of BCP using chicken eggshells through balance of ion-exchange and dissolution-reprecipitation reactions.Cell culture results showed that the BCP products were non-cytotoxic to MC3 T3-E1 cells,which may be used for bone substitute materials in future.

自固化磷酸钙人工骨修复骨缺损的临床应用

目的:探讨自固化磷酸钙人工骨(CPC)填充修复骨缺损的临床效果。方法:骨缺损94例,男59例,女35例;年龄11~72岁,平均39.4岁。骨缺损部位:胸腰椎38例,跟骨25例,胫骨15例,股骨7例,肱骨近端3例,桡骨远端5例,近节指骨1例。骨缺损原因:骨折塌陷复位后骨缺损63例,骨髓炎20例,骨囊肿6例,骨纤维异常增殖症4例,内生软骨瘤1例。骨缺损范围为1cm×1cm^4cm×20cm,用CPC填充修复,CPC充填量为3~42g,其中单纯CPC填充修复74例(胸腰椎骨折行椎体成形38例,骨折复位后空腔充填25例,良性骨肿瘤病灶刮除后充填11例),载药CPC填充修复骨髓炎20例。结果:所有患者均获随访,随访时间14~48个月,平均29.6个月。全部患者术后未见过敏或毒性反应,无皮疹或高热,血钙、磷、碱性磷酸酶均正常,切口无瘙痒感。随访时X线片显示,植入CPC与宿主骨接触紧密,界面处未见间隙存在,骨缺损处的解剖形状完全或大部分恢复,未见脱落现象,随访时部分患者CPC部分降解成骨。9例发生术后伤口渗出,为淡黄色清亮稀薄分泌物,细菌培养阴性,经换药后伤口愈合良好。结论:CPC填充修复骨缺损安全有效,并发症少,是理想的骨替代品,载药CPC是治疗骨髓炎的理想方法。

兔骨髓基质干细胞体外培养复合β-磷酸三钙进行胸椎后侧融合实验研究

[目的]评价β-磷酸三钙复合骨髓基质干细胞为骨移植替代物进行脊柱融合的效果。[方法]60只兔子分四组进行胸椎后路融合:Ⅰ组(组织工程化骨即β-TCP复合BMSCs),Ⅱ组(β-TCP+自体红骨髓),Ⅲ组(单纯β-TCP),Ⅳ组(自体髂骨)。术后12周处死其余动物进行放射学、手工力学和组织学检查。[结果]从影像学和手工力学比较,Ⅰ组的融合率高于Ⅱ、Ⅲ、Ⅳ组且有统计学差异。组织学上,Ⅰ组新骨形成量较多,陶瓷微孔内部充满新生骨;Ⅱ组骨小梁形成量较Ⅰ组少,为新生骨与纤维组织混杂;Ⅲ组陶瓷骨颗粒微孔内多为结缔组织,新生骨的量少,只见少量新生骨贴附于陶瓷骨表面;Ⅳ组在椎板与移植骨的交界处有稀疏的新生骨小梁形成。[结论]β-TCP复合BMSCs是脊柱融合自体骨的良好替代物。

多孔明胶微球/磷酸钙骨水泥的制备及其性能研究

[目的]制备多孔明胶微球/磷酸钙骨水泥,并于体内体外研究其各种性能。[方法]双相乳化冷凝聚合法制备明胶微球,以不同比例与磷酸钙骨水泥复合(0%,2.5%,5%),制备多孔磷酸钙骨水泥,测定材料孔径率及抗压强度,筛选出最佳比例。消化法培养成骨细胞接种于常规及多孔磷酸钙骨水泥支架上,扫描电镜观察细胞形态;不同材料浸提液(0%,2.5%明胶微球/磷酸钙骨水泥及聚苯乙烯)分别与成骨细胞共培养,以MTT法测定细胞增殖率,试剂盒检测碱性磷酸酶水平。将磷酸钙骨水泥及2.5%明胶微球/磷酸钙骨水泥分别植入山羊椎体内,6个月后收集标本,分别进行X线影像学及组织学观察,评估其降解情况。[结果]不同比例明胶微球/磷酸钙骨水泥的总孔径率、大孔率及抗压强度分别为:38.7%、0%、12.1MPa(0%);67.5%、40.6%、8.0MPa(2.5%);72.2%、45.6%、5.0MPa(5%)。成骨细胞在明胶微球/磷酸钙骨水泥上生长良好,细胞增殖及碱性磷酸酶水平均明显高于单纯磷酸钙骨水泥组,与聚苯乙烯组未见明显差异。多孔明胶微球/磷酸钙骨水泥6个月后在体内大部分已降解,而磷酸钙骨水泥未见明显降解。[结论]复合明胶微球可显著提高磷酸钙骨水泥的孔径率促进其降解,增加其生物活性,这种多孔磷酸钙骨水泥可作为非负重部位的骨替代物。

新型可注射性磷酸钙骨水泥对松质骨成骨作用的实验研究

目的:研制一种新型的、可注射的磷酸钙骨水泥,并测试该骨水泥的成分、理化学特性及其在松质骨内的生物降解和成骨特性,探讨该骨水泥在松质骨内的代谢情况.方法:根据相关文献合成一种含有β-磷酸三钙、磷酸二氢钙、碳酸钙和纳米相羟基磷灰石的磷酸钙骨水泥,并用含藻酸钠的液相成分将该骨水泥调制成可用注射器和16号穿刺针操作的注射物.在新西兰大白兔的股骨髁部钻取直径为2mm的骨洞,注入该骨水泥.在术后4、8、12、16周分别取标本,骨脱钙后石蜡包埋并行HE染色,光镜下观察该骨水泥在松质骨内的降解及新骨再生情况.扫描电镜观察骨-骨水泥界面的超微结构.结果:采用Gillmore双针法测试该型骨水泥的初凝时间为25～30min,终凝时间为17～20h,扫描电镜发现该骨水泥的颗粒较小、孔隙率较高.术后切片见骨水泥在松质骨内相容性良好.4周时骨水泥在体内开始降解,12周为降解反应的高峰期,16周降解反应基本完成,降解同时有大量的骨小梁生成.结论:该型磷酸钙骨水泥可操作性强、生物相容性好、具有骨传导和骨诱导作用,有望成为老年骨质疏松性椎体压缩骨折治疗中较好的填充剂.

自固化磷酸钙人工骨体内植入长期实验研究

目的 :自固化磷酸钙 (CPC)是新型的非陶瓷型羟基磷灰石类人工骨材料。本文观察了CPC植入体内的实验结果。方法 :将术中预制成形的CPC植入兔股骨髁处缺损和肌肉内 ,观察 18个月。结果 :CPC只引起一过性的炎症反应 ,与骨直接愈合。 12个月时CPC降解约 12 % ,18个月时约为 19% ,降解处由骨组织替代。CPC与骨为界面结合 ,CPC的降解为溶解降解 ,是两个重要发现。结论

磷酸钙骨水泥的研究进展

磷酸钙骨水泥 (CPCs)是由多种磷酸钙成分在体内直接结晶而成的 ,其终产物有良好的组织相容性、生物降解性和骨引导活性 ,具有一定的抗压强度。动物实验和临床应用研究表明 。

携载rhBMP-2微球的新型可注射自凝固复合人工骨的制备及特性研究

[目的]制备一种具有良好降解性和成骨活性、可注射的自凝固新型骨修复材料。[方法]制备携载rh-BMP-2的聚乳酸与聚乙醇酸共聚物(PLGA)微球,并将其与rhBMP-2/磷酸钙骨水泥(CPC)复合,制备出rhBMP-2/PLGA微球/CPC复合人工骨。探讨了材料的特性,包括形貌、固化时间、抗压强度及反映材料体外降解速度的指标—体外降解液Ca、P浓度变化,测定复合材料rhBMP-2的释药速度及体外诱导MSCs细胞成骨分化的能力。[结果]与单纯CPC-rhBMP-2相比,复合材料的固化时间少量增加,抗压强度下降明显。体外降解速度及体外释药明显提高,释放的rhBMP-2具有骨诱导活性。[结论]rhBMP-2/PLGA微球/磷酸钙骨水泥新型复合人工骨是具有良好应用前景的骨修复材料。

优化配方的CPC/DBM/rhBMP-2复合材料在体内的超微结构和组织学特征

目的探讨磷酸钙骨水泥(CPC)/脱钙骨基质颗粒(DBM)/重组人骨形成蛋白-2(rhBMP-2)复合材料在骨内的超微结构和组织学特征,评价该材料的成骨性能。方法预制兔DBM,按0.2的DBM质量比制作CPC/DBM/rhBMP-2复合材料。将复合材料(A组,n=12)、CPC(B组,n=10)、医用骨水泥(C组,n=7)分别植入兔股骨髁部骨缺损,在植入后第6、12、24周取材进行组织学和扫描电镜观察。结果术后第6周,A组中复合材料-骨界面模糊,宿骨发出纤维连续通过界面,编织骨样结构开始向材料内部长入。第12周,A组中血管和成骨细胞在复合材料内部生长,产生新骨。第24周,A组中骨缺损已修复,形成骨性连接,材料大部分被新骨替代。B组术后第6周CPC-骨界限清晰,未见新骨向材料内部长入,第24周骨缺损部位仍为CPC填充,材料内部未见新骨出现。C组材料直至第24周尚未与宿骨形成任何连接。A组材料在成骨细胞活性、血管化程度和新骨生长速度方面均优于B组。结论将DBM质量比为0.2的复合材料植入骨缺损内可以促进细胞、血管、新骨的长入,且易降解及被自体骨替代。

杜仲叶提取物/CPC复合载体对大鼠成骨细胞作用的实验研究

目的:观察不同浓度的杜仲叶提取物及其与CPC复合载体对MC3T3E1大鼠成骨细胞的影响。方法:将培养的MC3T3E1大鼠成骨细胞分为5组:空白组和0、0.152、0.304、0.608 mg/ml不同浓度杜仲叶提取物/CPC复合载体培养组。应用细胞增殖、MTT、扫描电镜法观察不同浓度杜仲叶提取物/CPC复合载体对体外培养成骨细胞48 h的增殖活性及生长、附着的影响。结果:杜仲叶提取物/CPC复合载体可促进成骨细胞的增殖率,尤其以浓度为0.152 mg/ml、0.304 mg/ml时作用较为明显(P<0.05)。结论:杜仲叶提取物/CPC复合载体具有促进成骨细胞的增殖和生长,以及附着的作用。

自制磷酸钙骨水泥的生物相容性和安全性

目的 研究自制磷酸钙骨水泥 (CPC)的生物相容性和安全性 ,为临床应用提供实验依据。 方法 采用浸提法制备自制磷酸钙骨水泥生理盐水和培养液浸提液 ;采用 MTT法进行细胞毒性试验 ;应用平板掺入法进行Ames试验 ;在小鼠腹腔内注射 CPC浸提液 ,取胸骨髓制片行微核试验 ;采用分光光度法进行溶血试验 ;通过新西兰兔骶棘肌及股骨髁内植入法行植入试验。 结果 自制 CPC的细胞毒性为 级 ;对健康人血的溶血率 <5 % ;Ames试验及微核试验均呈阴性 ;肌肉及骨内植入后无明显炎症反应 ,CPC与周围骨组织可达生物结合。 结论 自制 CPC无细胞毒性 ,无致突变、致畸、致癌作用 ,无溶血作用 ,植入后无炎症反应 ,可以与骨组织生物结合 。

可注射磷酸钙骨水泥联合骨形态发生蛋白-2治疗老年肱骨近端骨折疗效分析

目的采用回顾性分析方法,观察可注射磷酸钙骨水泥(calcium phosphate cement,CPC)联合重组骨形态发生蛋白(recombinant human bone morphogenetic protein,rh BMP-2)作为植骨材料在老年肱骨近端骨折中的临床疗效和安全性。方法对59例老年肱骨近端骨折手术复位后的骨缺损分别采用可注射rh BMP-2/CPC(实验组)和单纯CPC(对照组)进行充填,并用PHILOS接骨板进行内固定。比较两组患者术后Lane-Sandhu X线评分和肩关节功能的差异。结果全部病例经过平均14.2个月随访。切口局部无搔痒感或疼痛。随访发现实验组术后平均20.8周获得骨性愈合,优于对照组的25.8周。通过Lane-Sandhu评分结果显示:实验组与对照组的X线评分比较差异有统计学意义(P<0.05)。而实验组和对照组对比术后关节功能评分提示:运用可注射rh BMP-2/CPC人工骨患者在术后1年的Neer关节功能评分表结果优于单纯运用CPC人工骨患者(P<0.05)。结论可注射rh BMP-2/CPC具有安全、方便、副作用小、充填效果确实等优点,能有效避免复位后骨量的再丢失,可促进骨折的愈合过程,是充填老年肱骨近端骨折骨缺损的较佳方法之一。

优化配方的磷酸钙骨水泥/脱钙骨基质颗粒/重组人骨形成蛋白-2复合材料降解性能的影像学和组织学评价

目的探讨磷酸钙骨水泥（CPC）/脱钙骨基质颗粒（DBM）/重组人骨形成蛋白-2（rhBMP-2）复合材料在体内的影像学征象和组织学特征,评价该材料的降解性能。方法预制兔DBM,将其与rhBMP-2充分混匀,真空下形成rhBMP-2/DBM复合物,后者与CPC按DBM∶CPC质量比2∶8的比例制作CPC/DBM/rhBMP-2复合材料,其中含rhBMP-2的量约1.2mg/cm3。将复合材料（A组,n=12）、CPC（B组,n=12）分别植入兔股骨髁部骨缺损和股后肌肉内,于植入后6、12、24周每组各处死4只实验动物,进行X线摄片和组织学观察。结果X线摄片观察显示：A组术后6周植入髁部缺损的材料边缘变得不规则;第12周材料失去原有外形,轮廓变小;第24周材料大部分被吸收,髓腔部分再通。术后6-24周,A组植入肌肉内的复合材料轮廓逐渐变小,密度逐渐减低,B组植入髁部缺损和肌肉内的CPC轮廓、密度均无明显变化。组织学观察显示：A组术后第6周可见编织骨样结构长入植入髁部的复合材料内部;第12周材料内部产生新骨;第24周骨缺损已修复,材料残留少部分未被吸收,大部分被新骨替代。A组术后6-12周可见纤维组织长入植入肌肉内的复合材料内部,第24周仅少部分材料残留未被吸收。B组植入髁部缺损和肌肉内的CPC材料于术后6-12周未见新骨和纤维组织长入,第24周骨缺损部位仍为CPC填充,材料内部未见新骨和纤维组织出现。结论与CPC比较,优化配方的复合材料在体内易降解并容易被自体骨替代。

PGA/β-磷酸三钙骨组织工程支架的制备与性能

目的：制备PGA／β-磷酸三钙（β—TCP）支架并研究其物理性能。方法：以PGA与β—TCP为材料，六氟异丙醇（HFIP）为溶剂，以氯化钠颗粒（颗粒尺寸：425～500μm）为制孔剂，按PGA与β～TCP质量比1：1（A组）与1：3（B组），采用改良溶液浇铸一离子沥滤的方法制备PGA／β-TCP骨组织工程复合支架材料。借助扫描电镜对其微结构进行观察，并测试不同质量比的PGA／β-TCP骨组织工程支架复合材料的物理、力学性能。结果：B组0．13gPGA／0．39gp—TCP支架材料的抗压缩强度大于A组0．13gPGA／0．13gB—TCP，B组抗压缩强度值为（731．283±55．214）kPa，A组为（173．833±36．140）kPa，差异有统计学意义（P〈0．05）。A、B组支架材料孔隙率均大于85％，A组孔隙率（93．1±0．7）％大于B组的（89．3＋0．6）％，差异有统计学意义（P〈0．05）。SEM照片可见2组支架材料均为多孔三维架构，孔径均为200～300μm，孔隙的连通性好。β-TCP均匀地分散于聚合物中，B组支架材料中β-TCP颗粒明显多于A组。结论：质量比1：3的PGA／β-TCP支架材料有望成为一种理想的骨组织工程支架材料。