New scaffold for recombinant human bone morphogenetic protein-2

A bioactive and resorbable scaffold is necessary to exhibit the osteoinductive potency of recombinant human bone morphogenetic protein-2 (rhBMP-2). In a previous study, we found that synthetic octacalcium phosphate (OCP) enhances bone regeneration and is replaced by newly formed bone after it is resorbed. We hypothesized that OCP may be useful as an effective scaffold for rhBMP-2 to enhance bone regeneration. To test this hypothesis, the present study was designed to investigate whether an OCP/BMP composite implant could more effectively enhance bone regeneration. A critical-sized defect was made in a rat calvarium and 1. 15 mg of OCP combined with 10 microg of rhBMP-2 (OCP/BMP 10 microg), 2. 15 mg of OCP combined with 1 microg of rhBMP-2 (OCP/BMP 1 microg), or 3. OCP (OCP alone) was implanted into the defect and fixed at 4 or 8 weeks after implantation. The percentage of newly formed bone (n-Bone%) in the defect was determined by a histomorphometrical analysis. A statistical analysis showed that n-Bone% with OCP/BMP was significantly higher than that with OCP at both time points, whereas the difference in n-Bone% between OCP/BMP 10 microg and OCP/BMP 1 microg was not significant. The present results suggest that OCP can be used as an effective scaffold for rhBMP-2 and this OCP delivery system may be able to reduce the standard effective dose of rhBMP-2, which would be beneficial because low doses (<100 microg/g OCP) of rhBMP-2 enhance bone regeneration.     

Optimized use of a biodegradable polymer as a carrier material for the local delivery of recombinant human bone morphogenetic protein-2 (rhBMP-2)

To improve the efficacy of a block copolymer of poly-d, l-lactic acid with randomly inserted p-dioxanone and polyethylene glycol (PLA-DX-PEG) as a drug delivery system for recombinant human bone morphogenetic proteins (rhBMPs), we examined the relationship between the volume of PLA-DX-PEG, the dose of rhBMP-2 and osteoinduction in a mouse model of ectopic bone formation. In a series of studies, we compared the size and bone mineral content (BMC) of ectopically induced bone by PLA-DX-PEG and collagen sponges carrying different quantities of rhBMP (0, 1, 2, 5, 10, 20 microg). An additional experiment was designed to investigate how a range of PLA-DX-PEG polymer volumes (15, 30, 60, 90 mg) with a fixed rhBMP concentration (0.01 wt%), altered the size and BMC of the induced ossicle. The influence of polymer volume was also examined in a further experiment wherein a fixed amount of rhBMP was placed in a range of PLA-DX-PEG copolymer volumes to give different concentrations of the protein per implant (0.02-0.0017 wt%). The results indicate that the bone yields were linearly dependent on the dose of rhBMP and also were proportional to the polymer volume above the minimal concentration of rhBMP-2 (0.0017 wt% in this series). The optimal concentration of rhBMP-2 in PLA-DX-PEG was 0.003 wt% in mice. The data provide important insights into the fabrication of implants that provide efficacious delivery of rhBMP-2 using the lowest possible dose of this expensive osteoinductive protein. This information will be of value for the clinical use of BMPs.     

重组人骨形态发生蛋白2/骨修复材料的制备与性能

BACKGROUND: It has become a hotspot to prepare the bone repair material that exhibits natural bone structure and is used in combination with biological factors. OBJECTIVE: To prepare the recombinant human bone morphogenetic protein-2 (rhBMP-2)/bone repair material, and to evaluate its capacities of release, activity and ectopic osteoinduction. METHODS: A collagen-binding domain was added to the N-terminal of native rhBMP-2 that allowed bind to collagens in the bone repair material. Then, rhBMP-2/bone repair material was obtained through freeze-dried method. The releasing ability of rhBMP-2 in vitro was assayed by ELISA. C2C12 cell lines were loaded to the composite material with 0.25, 0.5 and 1 µg rhBMP-2, respectively. Afterwards, alkaline phosphatase activity was detected at 72 hours. The composite materials with 0, 2, 5 and 10 µg rhBMP-2 were implanted into the quadriceps of Sprague-Dawley rats, respectively. Alkaline phosphatase activity and the newly formed bone were detected at 2 and 4 weeks after implantation. The CY-7-labeled composite material was implanted into the quadriceps of Sprague-Dawley rats to observe its stability. RESULTS AND CONCLUSION: Substantially no rhBMP-2 from the rhBMP-2/bone repair material was released within 45 days. The alkaline phosphatase activity of C2C12 was in a rise with the increased concentration of rhBMP-2. The stability of the composite material in vivo was better, the alkaline phosphatase activity and ectopic bone formation increased as the concentration of rhBMP-2 rose. To conclude, the rhBMP-2/bone repair material preserves the stability of rhBMP-2, and improves ectopic osteoinduction ability.     

Immobilized recombinant human bone morphogenetic protein-2 enhances the phosphorylation of receptor-activated Smads

Bone morphogenetic protein (BMP)-2 plays an important role in bone growth and regeneration; however, BMP-2 is easily lost by diffusion through body fluid and has some inhibitory pathways. To address this problem, we previously immobilized recombinant human BMP-2 (rhBMP-2) on succinylated type I atelocollagen. Here, we examined the effect of immobilized rhBMP-2 in vitro and vivo. In ST2, MC3T3-E1, and C2C12 cells, alkaline phosphatase activity, which is a marker of osteoblast differentiation, was enhanced more by immobilized than nonimmobilized rhBMP-2. In addition, the phosphorylation of receptor-activated Smads, part of the signaling pathway activated by BMP-2, was prolonged by immobilized rhBMP-2 in these cells. Furthermore, implantation of immobilized rhBMP-2 into the backs of rats promoted the formation of mature bone-like structure. These results demonstrate that immobilized rhBMP-2 has higher bioactivity than nonimmobilized rhBMP-2, and, therefore, immobilization of rhBMP-2 can prolong BMP signaling.     

缓释型重组人骨形态发生蛋白2/壳聚糖生物骨修复材料诱导骨形成

背景：重组人骨形态发生蛋白2在体内半衰期短、易降解代谢,达不到理想的骨再生效果。 目的：制备缓释型重组人骨形态发生蛋白2/壳聚糖生物骨修复材料,并观察其缓释性能、骨诱导活性。 方法：将重组人骨形态发生蛋白2与壳聚糖混合制备壳聚糖膜,涂覆于生物骨修复材料表面,ELISA方法检测其体外释药性能。茜素红染色检测缓释型人骨形态发生蛋白2/壳聚糖生物骨材料、重组人骨形态发生蛋白2生物骨材料、单纯骨填充材料诱导C2C12细胞骨钙蛋白的形成,观察其诱导成骨细胞能力。同时将3种骨修复材料植入清洁级KM小鼠股部肌袋内,2周后检测新生骨Ca2+离子含量,评价其异位骨诱导能力。 结果与结论：材料表面的壳聚糖膜分布均匀,负载的重组人骨形态发生蛋白2呈团簇状。重组人骨形态发生蛋白2/壳聚糖生物骨修复材料体外释药存在突释,前4 d释放量达总药量的50%,持续至12 d,释药量达到90%,第18天时释放完全。与单纯骨填充材料、重组人骨形态发生蛋白2生物骨材料相比,缓释型人骨形态发生蛋白2/壳聚糖生物骨修复材料诱导C2C12细胞向成骨晚期分化能力与异位骨形成能力显著增强(P < 0.05)。结果提示缓释型人骨形态发生蛋白2/壳聚糖生物骨修复材料缓释性能好,促进骨形成能力强。     

重组人类骨形态蛋白2复合自固化磷酸钙材料在体内的血管化

背景：深筋膜瓣促进组织工程骨血管化是一种成熟的技术,但动物种属不同、植入材料不同均会使血管化的结果产生较大的差异。 目的：比较复合重组人类骨形态蛋白2的自固化磷酸钙人工骨和单纯的自固化磷酸钙人工骨在比格犬带蒂筋膜瓣内的血管再生能力。 方法：分别将复合重组人骨形态蛋白2的自固化磷酸钙人工骨和单纯的自固化磷酸钙人工骨包裹于12只成年比格犬腰背部两侧带蒂深筋膜瓣中,于术后第2,4,8,16周各随机选取3只动物摘取血管化标本,进行大体观察、苏木精-伊红染色、Masson染色及血管内皮细胞Ⅷ因子相关抗原(ⅧRAg)免疫组织化学染色观察比较新血管的生成情况。 结果与结论：在材料植入后4周、8周和16周,两组均发现带蒂筋膜与植入材料接触区出现明显血管化,并随时间延长,向材料内部延伸;实验组相对血管面积百分比和阳性染色的面密度值在2,4,8,16周时均高于对照组。结果显示两种人工骨在筋膜内均有一定的血管化能力,但复合重组人骨形态蛋白2的自固化磷酸钙人工松质骨在体内的血管化较单纯自固化磷酸钙人工松质骨更为明显。     

重组人骨形成蛋白-2-珊瑚人工骨复合物在拔牙窝牙槽骨修复中的作用

目的:探讨重组人骨形成蛋白-2与珊瑚人工骨复合物(复合骨 )在拔牙窝修复中的作用。方法:拔除 12只成年狗两侧上颌第二及第三切牙,并去除牙槽窝之间的牙槽间隔,一侧随即植入复合骨,对侧植入珊瑚人工骨(珊瑚骨 )作为对照。并于植入后 4、8、12周取材,采用组织学观察、图像分析和 [⁹⁹Tc^m]-MDP核素骨显像等方法比较两种植入材料在牙槽窝中的骨修复能力。结果:复合骨植入牙槽骨后,材料被逐渐降解吸收,新骨不断生成,12周后,植入材料完全被成熟的骨组织取代;图像分析结果显示不同时间复合骨组新骨形成的比值显著高于珊瑚骨组(P <0.05 );4和 8周复合骨组核素浓聚程度高于珊瑚骨组,12周两组核素浓聚程度差异不明显。结论:复合骨在牙槽骨缺损中的骨修复能力和修复效果明显优于珊瑚骨.     

A comparison of the surface characteristics and ion release of Ti6Al4V and heat-treated Ti6Al4V

This work seeks to investigate the nanosurface characteristics and ion release for a Ti6Al4V alloy prepared by various methods (as received and heat treated at 1300 degrees C for 2 h) with three different passivation treatments (34% nitric acid passivation, 400 degrees C heating in air, and aging in 100 degrees C deionized water). The surface and nanosurface composition are not related to the surface passivation treatments and experimental materials as evaluated by energy dispersive spectroscopy and X-ray photoelectron spectroscopy (XPS) analyses. After passivation and autoclaving treatments, the specimens were immersed in 8.0 mM ethylenediaminetetraacetic acid (EDTA) in Hank's solution and maintained at 37 degrees C for periods of time up to 16 days. The 400 degrees C treated specimens exhibit a substantial reduction in constituent release, which may be attributed to the thicker thickness and rutile structure of the surface oxides. After soaking in Hank's-EDTA solution, a significant time-related decrease in constituent release rate is observed for all kinds of specimens throughout the 0-16 day experimental period. The thicker oxides may be a factor in the improved dissolution resistance. Upon immersion, nonelemental Ca and P are both detected on the surfaces of all kinds of specimens by XPS analysis, and this could be explained by the existence of two types of hydroxyl groups (acidic and basic OH groups) on the oxide surface of the specimens.     

人重组骨形态蛋白-2在脊柱融合中并发症的研究

自体骨移植物具有天然的骨诱导和骨传导特性,是骨移植材料中的金标准,但其存在局限性。目前重组人骨形态发生蛋白-2(rhBMP-2)被广泛应用于临床中以提高脊柱融合率。但其应用范围远超美国食品药品监督管理局(FDA)标准,同时也出现了很多并发症。因此研制出新型骨修复材料成为了目前亟待解决的问题。     

不同有机溶剂对缓释重组人骨形态发生蛋白2微胶囊的影响

背景：查阅文献发现在采用复乳溶剂挥发法制备缓释重组人骨形态发生蛋白2微胶囊的过程中,可以二氯甲烷、乙酸乙酯、丙酮或不同有机溶剂混合物等作为油相,而孰优孰劣尚无定论。 目的：优化包封重组人骨形态发生蛋白2微胶囊制备方法,比较不同有机溶剂对微胶囊产生的影响。 方法：分别以二氯甲烷(A组)、二氯甲烷与乙酸乙酯混合液(B组)、乙酸乙酯(C组)、乙酰丙酮(D组)等4种不同类型的有机溶剂作为油相,以聚乳酸-聚乙二醇-聚乳酸三嵌段共聚物为囊材,采用复乳溶剂挥发法制备缓释重组人骨形态发生蛋白2微胶囊,检测微囊的粒径、形态及包封率。将制备的微胶囊分别与第3代大鼠骨髓间充质干细胞共培养,培养14 d后检测碱性磷酸酶活性。 结果与结论：A组微囊形态均一规则,微囊粒径小(4-10 µm),包封率最高;B组、C组微囊粒径分布范围较大,包封率中等;D组微囊基本难成形,包封率最低。A组、B组、C组碱性磷酸酶活性明显高于D组(P < 0.05),A组、B组均明显高于C组(P < 0.05),A组与B组之间无明显差异。表明以二氯甲烷作为有机溶剂制备的重组人骨形态发生蛋白2微胶囊包封率高,形态优良且能很好地保护重组人骨形态发生蛋白2的生物活性。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     

重组人骨形成蛋白－2在大肠杆菌中的表达、纯化和复性

目的:通过对大肠杆菌表达重组人骨形成蛋白－2的复性研究,得到高活性的重组人骨形成蛋白－2。方法:在大肠杆菌中通过温度诱导表达重组人骨形成蛋白－2经过Triton X-100清洗之后,又通过DEAE离子交换层析纯化包涵体,包涵体在8 mol/L 尿素变性溶解,在氧化－还原(还原型和氧化型谷胱甘肽)复性系统中,通过简单的稀释复性,通过肝素亲和层析一步纯化法纯化重组人骨形成蛋白－2,最后通过诱导C2C12细胞产生碱性磷酸酶检测重组人骨形成蛋白－2活性。结果:温度诱导表达重组人骨形成蛋白－2是以包涵体单体的形式存在,经过几步纯化后,得到高纯度的包涵体。重组人骨形成蛋白－2在不同氧化－还原剂比例,和不同小分子化学辅助剂浓度中复性,得到复性的效率也不同。亲和层析纯化后,本实验得到重组人骨形成蛋白－2的生物学活性比商业化的重组人骨形成蛋白－2更高。结论:重组人骨形成蛋白－2属于转化因子－β家族,此复性方法可能应用于此家族的其他成员同时得到成本低、产量高的重组人骨形成蛋白－2,可能为临床应用创造了良好的条件。     

Release of recombinant human bone morphogenetic protein-2 from heterocyclic methacrylate polymer systems.

The release of recombinant human bone morphogenetic protein-2 (rhBMP-2) from three room temperature polymerising methacrylate systems has been studied. These all contained poly(ethyl methacrylate) powder, but the monomer liquids comprised, respectively, tetrahydrofurfuryl methacrylate (THFM), 90/10 THFM/hydroxyethyl methacrylate (HEMA), and 70/30 THFM/ HEMA. In all cases, rhBMP-2 was released, but the addition of 10% HEMA accelerated release (a nine-fold increase in diffusion coefficient); a further increase to 30% HEMA had no additional effect. For most of the release process, a diffusion process operated, although the early stages were not well defined. At the end of the 15 day period, the release, respectively, for the PEM/THFM, PEM:90/10 THFM/HEMA and PEM:70/30 THFM/HEMA systems was 596, 878 and 923 ng (i.e. up to 92% of the rhBMP-2 added).     

Tissue reaction at the implantation of recombinant human bone morphogenetic protein-2 into the skeletal muscle

Bone morphogenetic protein (BMP) is a unique cytokine that induces bony tissue in soft tissue. Tissue reactions at and around the implantation of recombinant human BMP-2 (rhBMP-2) into the soft tissue of rats and nonhuman primates were investigated. At the osteoinduced site of rats, massive trabeculae-lined osteoblasts and rich marrow were observed. At and around the nonosteoinduced sites of nonhuman primates, large clear nuclei were observed in reaction to rhBMP-2 implantation. The surrounding area was visually classified into zones 1, 2 and 3. Zone 3 was near the center of the implant. The area of nuclei, the major axis, the minor axis and the ratio of minor axis per major axis were image-analyzed in the histological views. In zones 1, 2 and 3, the nuclear areas were 18.0 (3.1) mean (SD); unit micron2, 33.4 (5.61) and 110.1 (23.7), respectively. The major axes of nuclear ellipses were 7.45 (0.22) (unit micron), 7.76 (0.26), and 13.9 (1.88), respectively. The minor axes were 3.07 (0.53), 5.59 (0.95) and 10.1 (1.35), respectively. The ratios of minor axis per major axis of nuclear ellipses were 0.4 (0.57), 0.72 (0.11) and 0.73 (0.11) in zones 1, 2 and 3, respectively. These results showed that in zones 2 and 3 cell and tissue reactions were marked against rhBMP-2 implantation.     

骨形态发生蛋白2与4在生长发育高峰期骨性Ⅱ类错牙合畸形中的表达

背景：课题组以往研究证实,骨形态发生蛋白4对生长发育期下颌骨的生长有促进作用,而骨形态发生蛋白2是否能与骨形态发生蛋白4相互促进下颌骨生长目前未见有相关报道。 目的：检测生长发育高峰期骨性Ⅱ类错牙合畸形患者血液中骨形态发生蛋白2和骨形态发生蛋白4的表达情况,以探究骨形态发生蛋白2和骨形态发生蛋白4的表达量与下颌骨生长的关系。 方法：生长发育高峰期骨性Ⅰ类错牙合畸形患者为Ⅰ组,以下颌后缩为主的骨性Ⅱ类错牙合畸形患者为Ⅱ组,每组18人。采用实时荧光定量PCR(RT-PCR)分别检测两组血液骨形态发生蛋白2和骨形态发生蛋白4的表达。 结果与结论：骨性Ⅱ类错牙合畸形组中骨形态发生蛋白2 mRNA的表达量明显低于对照组骨性Ⅰ类错牙合畸形组(P < 0.05),骨性Ⅱ类错牙合畸形组中骨形态发生蛋白4 mRNA的表达量明显低于对照组骨性Ⅰ类错牙合畸形组 (P < 0.05),骨性Ⅱ组中骨形态发生蛋白2与骨形态发生蛋白4的表达有显著相关性。结果证实,骨形态发生蛋白2和骨形态发生蛋白4在生长发育高峰期的表达量均降低与下颌骨发育不足有密切关系,且骨形态发生蛋白2和骨形态发生蛋白4相互协同,共同参与调节下颌骨的生长。     

Effects of calcium ion incorporation on bone healing of Ti6Al4V alloy implants in rabbit tibiae

The biocompatibility of calcium ion (Ca)-incorporated Ti6Al4V alloy implants, produced by hydrothermal treatment using a Ca-containing solution, was investigated. The surface characteristics were evaluated by scanning electron microscopy, thin-film X-ray diffractometry, Auger electron spectroscopy, and stylus profilometry. The viability of MC3T3-E1 cells on Ca-incorporated machined Ti6Al4V surfaces with different oxide thicknesses was compared with that on untreated machined Ti6Al4V surfaces with MTT assay. The osteoconductivity of the Ca-incorporated Ti6Al4V implants was evaluated by removal torque testing and histomorphometric analysis after 6 weeks of implantation in rabbit tibiae. Our results show that hydrothermal treatment with a Ca-containing solution produced a crystalline CaTiO(3) layer on Ti6Al4V surfaces, and calcium ions were gradually incorporated throughout the oxide layer. After immersion in Hank's balanced salt solution, a considerable apatite deposition was observed on all surfaces of the Ca-incorporated samples. Significant increases in cell viability (p<0.001), removal torque forces, and bone-to-implant contact values (p<0.05) were observed for Ca-incorporated Ti6Al4V implants compared with those for untreated Ti6Al4V implants.     

重组人骨形态发生蛋白-2结合纳米晶胶原基骨材料植骨融合在腰椎不稳症中的临床应用

目的观察重组人骨形态发生蛋白-2﹙rhBMP-2﹚结合纳米晶胶原基骨材料﹙nHAC﹚行腰椎间融合治疗腰椎不稳症的疗效。方法 2008年1月~2010年12月23例﹙27个节段﹚腰椎不稳患者,所有患者均行腰椎椎弓根螺钉固定系统,辅助以rhBMP-2结合nHAC椎间植入融合椎体。结果全部病例获随访,手术后平均随访13.5月,按照JOA评价标准,优14例,良6例,可3例。优良率86.9%。结论 rhBMP-2结合nHAC行腰椎间融合治疗腰椎不稳症是一种比较理想的治疗方法。     

Evaluation of an injectable silk fibroin enhanced calcium phosphate cement loaded with human recombinant bone morphogenetic protein-2 in ovine lumbar interbody fusion

The objective of this study was to investigate the efficacy of an injectable calcium phosphate cement/silk fibroin/human recombinant bone morphogenetic protein-2 composite (CPC/SF/rhBMP-2) in an ovine interbody fusion model. Twenty-four mature sheep underwent anterior lumbar interbody fusion at the levels of L1/2, L3/4, and L5/6 with random implantation of CPC/SF, CPC/rhBMP-2, CPC/SF/rhBMP-2, or autogenous iliac bone. After the sheep were sacrificed, the fusion segments were evaluated by manual palpation, CT scan, undestructive biomechanical testing, undecalcified histology, and histomorphology. The fusion rates of CPC/SF/rhBMP-2 were 55.56% and 77.78% at 6 and 12 months, respectively. The fusion was superior to all the biomaterial grafts in stiffness, and reached the same stiffness as the autograft at 12 months. The new bone formation was less than autograft at 6 months, but similar with that at 12 months. However, the ceramic residue volume of CPC/SF/rhBMP-2 was significantly decreased compared with CPC/SF and CPC/rhBMP-2 at both times. The results indicated that CPC/SF/rhBMP-2 composite had excellent osteoconduction and osteoinduction, and balanced degradation and osteogenesis.     

Biodegradable gelatin microparticles as delivery systems for the controlled release of bone morphogenetic protein-2

This work evaluated gelatin microparticles and biodegradable composite scaffolds for the controlled release of bone morphogenetic protein-2 (BMP-2) in vitro and in vivo. Gelatin crosslinking (10 and 40mM glutaraldehyde), BMP-2 dose (6 and 60ng BMP-2 per mg dry microparticles), buffer type (phosphate buffered saline (PBS) and collagenase-containing PBS), and gelatin type (acidic and basic) were investigated for their effects on BMP-2 release. Release profiles were also observed using poly(lactic-co-glycolic acid) (PLGA) microparticles with varying molecular weights (8300 and 57,500). In vitro and in vivo studies were conducted using radiolabeled BMP-2; the chloramine-T method was preferred over Bolton-Hunter reagent for radioiodination with this system. BMP-2 release from PLGA microparticles resulted in a moderate burst release followed by minimal cumulative release, while BMP-2 release from gelatin microparticles exhibited minimal burst release followed by linear release kinetics in vitro. Growth factor dose had a small effect on its normalized release kinetics probably because of an equilibrium between gelatin-bound and unbound BMP-2. Differences in release from acidic and basic gelatin microparticles may result from the different pretreatment conditions used for gelatin synthesis. The in vitro release kinetics for both gelatin microparticles alone and within composite scaffolds were dependent largely on the extent of gelatin crosslinking; varying buffer type served to confirm that controlled release relies on enzymatic degradation of the gelatin for controlled release. Finally, in vivo studies with composite scaffolds exhibited minimal burst and linear release up to 28 days. In summary, dose effects on BMP-2 release were found to be minimal while varying gelatin type and release medium can alter release kinetics. These results demonstrate that a systematic control of BMP-2 delivery from gelatin microparticles can be achieved by altering the extent of basic gelatin crosslinking.     

Restoration of segmental bone defects in rabbit radius by biodegradable capsules containing recombinant human bone morphogenetic protein-2

Recombinant human bone morphogenetic protein-2 (rhBMP-2) was encapsulated in biodegradable poly(DL-lactide-co-glycolide) (PLGA) capsules to regenerate bone by controlling the release rate of rhBMP-2. The rhBMP-2/PLGA capsules containing 12 microg of rhBMP-2 were implanted in seven 15-mm segmental defects of rabbits radii to examine the healing capacity of the rhBMP-2/PLGA capsules. For the control group, four segmental defects were left empty and two were implanted with ghost PLGA capsules. Healing of the defects was followed for 24 weeks and periodically evaluated by radiographs and histological examination. Mechanical testing was applied to three regenerated bone samples at 24 weeks postoperatively when the mature cortex was observed. Mechanical properties of regenerated bone were not significantly different from normal intact bone statistically. Histologically, the rhBMP-2/PLGA capsules disappeared completely during the process of bone regeneration. These results increased possibilities for clinical application of rhBMP-2/PLGA capsules.     

Surface hardening by anodizing and heat treatments of Ti6Al4V alloys for articular prostheses

This paper presents a study of the surface hardening of Ti6Al4V alloy produced by electrochemical anodizing and by different heat treatments, in addition to studying the annealing of the martensitic structure. Results of the combination of both methods produce hardening over 1300 HV and an important improvement on the tribological behaviour. These values could improve wear resistance of this alloy in applications like articular prostheses.