生物玻璃-纳米羟基磷灰石梯度涂层的生物相容性研究

目的对生物玻璃-纳米羟基磷灰石(BG-nHA)梯度涂层的生物相容性作初步的评价。方法用低温烧结法在钛合金表面制备生物玻璃纳米羟基磷灰石梯度涂层,利用L929细胞检测梯度涂层材料的细胞毒性。取体外分离培养扩增的人骨髓基质干细胞(hBMSC),接种于涂层材料上,通过绿色荧光蛋白染色、扫描电镜和MTT法观察细胞的黏附和生长情况。结果生物玻璃-纳米羟基磷灰石梯度涂层的细胞毒性分级为1级,人骨髓基质干细胞可以在涂层材料表面黏附和生长。结论生物玻璃-纳米羟基磷灰石梯度涂层有良好的生物相容性,具有潜在的临床应用前景。     

生物玻璃-纳米羟基磷灰石梯度涂层的制备及检测

目的研究生物玻璃-纳米羟基磷灰石梯度涂层(BG-nHA)的表征以及涂层与钛合金(Ti-6Al-4V)之间的结合能力。方法用低温烧结法在钛合金表面制备生物玻璃-纳米羟基磷灰石梯度涂层,通过SEM、能谱分析仪(EDS)、X射线衍射仪(XRD)、红外傅利叶变换分析仪(FITR)等对涂层表征进行检测,材料在Tris-HCL缓冲液中行浸泡试验,依据ISO13779-4:2002标准用抗拉试验测试梯度涂层在浸泡前后与金属基质之间的结合强度,同时测定涂层材料释放的离子和丢失重量。结果电镜结果显示梯度涂层呈多孔状,表面分布均匀的杆状纳米羟基磷灰石晶体,基底部与钛合金形成致密结合,未发现细微的裂纹。抗拉试验显示梯度涂层与钛合金结合强度达到(39.7±4.4)MPa。随着浸泡时间的延长,涂层材料的重量有部分丢失,释放的离子逐渐增加。结论采用低温烧结法可以制备生物玻璃-纳米羟基磷灰石梯度涂层,这种加入生物活性玻璃的梯度涂层可以加强涂层与钛合金的结合能力。     

钛合金表面新型生物玻璃/纳米羟基磷灰石涂层的细胞相容性评价

目的为检验前期制备的新型生物玻璃／纳米羟基磷灰石涂层的细胞相容性。方法在本实验中，采用L929成纤维细胞在涂层浸提液中的培养，检测了涂层的细胞毒性，采用人体骨髓基质干细胞存涂层上的培养，检测了涂层对人体骨髓基质下细胞增殖和代谢的影响。结果低于浓度的涂层浸提液（〈10％）埘L929细胞增殖具有促进作用，而高浓度的涂层浸提液（〉50％）对L929细胞的增殖具有抑制作用，其中100％的涂层浸提液对L929细胞的增殖抑制比例为20.9％，在细胞毒性分级中处于合格范围内。结论在培养早期，人体骨髓基质干细胞在涂层表面的增殖要优于对照组，涂层显示出良好的细胞相容性。由于合格的细胞毒性和良好的细胞相容性，该涂层的钛合金具有作为骨植入物的应用潜力。     

羟基磷灰石涂层与骨组织界面生物相容性与毒理学研究

依据卫生部新近制定的《生物材料和制品的生物学评价标准》(简称《标准》),确定五项评价项目,按照标准的生物学试验方法,对目前临床应用的羟基磷灰石制品进行系统研究。结果表明：国产羟基磷灰石制品除有轻微细胞毒性外,其致敏性、溶血性、致突变性和组织相容性均符合《标准》要求,临床应用安全。     

含氟羟基磷灰石涂层体外细胞相容性研究

在羟基磷灰石（HA）中掺入氟可以降低其在体内的溶解性，对提高钛合金植入体表面生物活性改性层（涂层）的长效性有着重要的意义。本研究采用溶胶-凝胶法在钛合金基板上制备了含氟羟基磷灰石（Ca10（PO4）6（OH）2-xFx）（FHA）涂层。X光衍射（XRD）和X光电子能谱（XPS）分析结果显示：本实验中获得的涂层是一个纯磷灰石晶相，含氟涂层中x为1．2。在体外成骨细胞相容性的研究中，以HA涂层为对照，通过定时细胞的计数测定了细胞生长曲线，用流式细胞仪法测定了细胞周期，用MTT比色法分析了涂层浸提液的细胞毒性。实验结果表明：在HA涂层中引入氟后，FHA涂层浸提液对细胞毒性级别为0级，该涂层不但没有对细胞产生毒性，而且会促进成骨细胞的贴壁生长，有着更好的细胞生长速度和增殖活性。     

壳聚糖/纳米羟基磷灰石分层复合支架的生物相容性研究

制备壳聚糖/纳米羟基磷灰石(CS/nHA)分层复合支架,对其进行细胞毒性评价.分离培养大鼠软骨细胞接种于支架,相差显微镜和扫描电镜观察细胞的黏附及生长情况.动物皮下埋植试验观察其组织相容性.实验结果证实壳聚糖/纳米羟基磷灰石分层复合支架具有良好的生物相容性,有望成为较好的骨软骨组织工程支架.     

纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥的生物相容性与体内降解研究

对制备的纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥的生物相容性及体内降解情况进行研究,为临床提供实验依据。参照GB/T16886医疗器械生物学评价标准和要求,对纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥进行急性细胞毒性试验、溶血试验、热源试验、急性全身毒性试验及体内植入试验等系列体内外生物学试验研究,以进行有效的生物相容性和安全性评价。纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥的溶血率小于国家规定的5%,在体外不引起溶血反应;浸提液注入动物体内后无死亡,活动进食正常;无细胞毒性反应;热原试验动物体温升高均在0.7℃以下,3只兔体温升高值的总数〈1.5℃,无致热作用;材料植入体内初期有轻度炎症反应,随植入时间延长逐渐减轻,材料也逐渐降解吸收。纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥具有良好的生物相容性和降解性能,具有临床开发应用前景。     

纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥的生物相容性与体内降解研究

对制备的纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥的生物相容性及体内降解情况进行研究,为临床提供实验依据.参照GB/T16886医疗器械生物学评价标准和要求,对纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥进行急性细胞毒性试验、溶血试验、热源试验、急性全身毒性试验及体内植入试验等系列体内外生物学试验研究,以进行有效的生物相容性和安全性评价.纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥的溶血率小于国家规定的5％,在体外不引起溶血反应;浸提液注入动物体内后无死亡,活动进食正常;无细胞毒性反应;热原试验动物体温升高均在0.7℃以下,3只兔体温升高值的总数＜1.5℃,无致热作用;材料植入体内初期有轻度炎症反应,随植入时间延长逐渐减轻,材料也逐渐降解吸收.纳米羟基磷灰石/羧甲基壳聚糖-海藻酸钠复合骨水泥具有良好的生物相容性和降解性能,具有临床开发应用前景.     

二氧化锆梯度复合羟基磷灰石生物陶瓷的制备及其体外免疫相容性

制备二氧化锆（ZrO2）梯度复合羟基磷灰石（HAP）生物陶瓷材料、ZrO2单纯复合HAP陶瓷材料及两种材料浸提液。检测梯度复合材料的截断面特征；在有及无植物血凝素（PHA）的情况下，检测材料浸提液对健康青年人末梢血单个核细胞（PBMC）的活化。结果表明：PHA作用72h，梯度复合组PBMC的增殖作用高于单纯复合组（P〈0．05）；两材料对PBMC的凋亡无差异（P〉0．05）；PHA作用24h，两材料对CD3／CD69表达率上差异均有统计意义（P〈0．01）。ZrO2梯度复合HAP生物陶瓷材料对PBMC的激活程度较轻，梯度复合技术有助于提高ZrO2-HAP生物陶瓷的免疫相容性。     

钛合金表面新型生物玻璃/羟基磷灰石涂层的体内动物实验

目的为促进钛合金植入体与骨的结合,在其表面制备了生物玻璃/羟基磷灰石复合涂层,并植入兔子股骨内进行动物试验,采用等离子喷涂羟基磷灰石涂层和未涂层的Ti6Al4V合金作为对照。方法种植到期的植入体取出后进行组织学切片,采用品红-苦味酸染色后进行组织学观察,采用SEM高倍观察种植体与骨的结合界面,并对骨接触率和凹槽内骨长入量进行了统计分析和比较。结果三种植入体都具有良好的生物相容性。Ti6Al4V合金与骨之间是一种形态固定,而生物玻璃/羟基磷灰石涂层、等离子喷涂羟基磷灰石涂层可与骨形成骨键合。生物玻璃/羟基磷灰石涂层在植入期间与基体没有脱落,同时其与骨的接触率和凹槽内骨长入量要明显高于其余两个植入体,显示出促进骨生长的作用。结论由于具有良好的生物相容性和促进新骨生长的能力,生物玻璃/羟基磷灰石涂层可加快植入体与骨的愈合速度,在骨替代修复方面显示出优势和广阔的应用前景。     

Adhesion of new bioactive glass coating.

A valuable alternative to the existing biomedical implant coatings is a bioactive glass (BAG) coating that is produced by reactive plasma spraying. A mechanical performance requirement that is of the utmost importance is the adhesion strength of the coating. Considering the application as dental implant, a new adhesion test (shear test), which was close to the service conditions, was designed. A Ti6Al4V rod (3 mm) with a sprayed BAG coating of 50 microm was glued with an epoxy glue to a hollow cylindrical counterpart and was used as such in the tensile machine. This test was evaluated by finite element analysis (FEA). Preliminary experiments showed that a conversion from shear to tensile adhesion strength is possible by using the Von Mises criterion (sigma = 3(1/2)tau), indicating that thin coatings of brittle materials can behave as a ductile material. The new coating technique was proved to produce a high quality coating with an adhesion strength of 40.1 +/- 4.8 MPa in shear and 69.4 +/- 8.4 MPa in tension. The FEA revealed that no one homogeneously distributed shear stress is present but several nonhomogeneously distributed stress components (shear and tensile) are present in the coating. This analysis indicated that real service conditions are much more complicated than standard adhesion tests.     

Composite surgical sutures with bioactive glass coating

A processing method was developed to coat polyglactin 910 (Vicryl) sutures with bioactive glass powder (45S5 Bioglass). High reproducibility and homogeneity of the coating in terms of microstructure and thickness along the suture length were achieved. Bioglass-coated sutures exhibited a high level of chemical reactivity in simulated body fluid (SBF), indicating their bioactive behavior. This was evident by the prompt formation of hydroxyapatite (HA) crystals on the surface after only 7 days of immersion in SBF. These crystals grew to form a thick HA layer (15 microm thickness) after 3 weeks in SBF. The tensile strength of the sutures was tested before and after immersion in SBF in order to assess the effect of the bioactive glass coating on suture degradation. The tensile strength of composite sutures was lower than that of as-received Vicryl sutures, 385 and 467 MPa, respectively. However, after 28 days of immersion in SBF the residual tensile strengths of coated and uncoated sutures were similar (83 and 88 MPa, respectively), indicating no negative effect of the HA layer formation on the suture strength. The effect of bioactive glass coating on the polymer degradation is discussed. The developed bioactive sutures represent interesting materials for applications in wound healing, fabrication of fibrous three-dimensional scaffolds for tissue engineering, and reinforcement elements for calcium-phosphate temporary implants.     

Biocompatibility and in vivo gentamicin release from bioactive sol-gel glass implants

The objective of this investigation was to study the compositional influence on the corrosion behavior of Ni-Cr-Mo dental casting alloys in acidic artificial saliva. Cyclic potentiodynamic and potentiostatic tests were used to evaluate the corrosion behavior of different Ni-Cr-Mo dental casting alloys in deaerated artificial saliva with pH 5 at 37 degrees C. Optical microscope observations were made following the cyclic potentiodynamic tests. Surface chemical analyses were characterized by X-ray photoelectron spectroscopy and auger electron spectroscopy following the potentiostatic tests. The results show that the corrosion resistance of the Ni-Cr-Mo casting alloys investigated is associated with the formation of passive film containing Ni(OH)(2), NiO, Cr(2)O(3), and MoO(3), on the surface. The pitting potential and passive range, respectively, were statistically different among the different Ni-Cr-Mo alloys. The Ni-Cr-Mo alloys with higher Cr ( approximately 21%) and Mo ( approximately 8%) contents had a much larger passive range in the polarization curve and were immune to pitting corrosion due to the presence of high Cr (maximum approximately 31-35%) and Mo (maximum approximately 12%) contents in the surface passive film. The presence of Ti lower than 4% in the Ni-Cr-Mo casting alloy had no effect on corrosion resistance. A pitting resistance equivalent (PRE) of about 49 could provide the Ni-Cr-Mo alloy with a good pitting corrosion resistance.     

生物活性玻璃陶瓷涂层与Hedgehog信号通路调控成骨

BACKGROUND: Bioactive glass ceramics (BGC) has been successfully applied as titanium alloy coating in the clinic. However, the correlation between Hedgehog signaling pathway and BGC coating in osteogenesis has not yet been reported. OBJECTIVE: To explore the correlation of Hedgehog signaling pathways and BGC coating in osteogenesis. METHODS: The BGC coating was prepared and observed by scanning and transmission electron microscopes. Primary cultured rat bone marrow mesenchymal stem cells were incubated onto the BGC coating. The expressions of bone morphogenetic protein 2 and Gliloma-association oncogene homoglog in the Hedgehog signaling pathway were detected using fluorescent quantitative RT-PCR, western blot assay, and immunofluorescence staining, and the cell migration ability was observed. RESULTS AND CONCLUSION: Electron microscopes showed that there were no cracks on the smooth BGC coating that had the dense mesoporous structure, and the coating thickness was 350 nm. The mRNA and protein expressions of bone morphogenetic protein 2 and Gliloma-association oncogene homoglog in the BGC group were significantly higher than those in the control group; and the expresssed bone morphogenetic protein 2 and Gliloma-association oncogene homoglog proteins interacted with each other in the process of osteogenesis. The cell migration ability in the BGC group was obviously enhanced compared with the control group. These results indicate that the BGC coating increases the expression of Gliloma-association oncogene homoglog, then further activates the Hedgehog signaling pathway, and finally accelerates the osteoblast proliferation in combination with bone morphogenetic protein 2.     

Biocompatibility of diamond-like carbon coating

Diamond-like carbon coating is an inert, impervious hydrocarbon coating with properties suitable for use in the biomedical field, particularly in orthopaedic implants. Mouse peritoneal macrophages and mouse fibroblasts were grown on tissue culture plates treated with diamond-like carbon and the biocompatibility assessed both biochemically and morphologically. This investigation showed that diamond-like carbon coating caused no adverse effects on cells in culture and therefore merits further investigation as a coating for biomedical use.     

Adhesion of bioactive glass coating to Ti6A14V oral implant

Bioactive glass (BAG) is a bioactive material with a high potential as implant material. Reactive plasma spraying produces an economically feasible BAG-coating for Ti6A14V oral implants. This coating is only functional if it adheres well to the metal substrate and if it is strong enough to transfer all loads. To examine these two properties an appropriate mechanical adhesion test, the moment test, is developed. This test quantifies under a realistic loading condition the corresponding functional adhesion strength to be >84 MPa in tensile. To get a qualitative insight in the BAG-coating behavior during loading the mechanical test was combined with finite element analysis, acoustic emission and microscopic analysis. These analyses showed that the coating withstands without any damage an externally generated tensile stress of 47 MPa. Not only the initial adhesion is determining for the implant quality, but more important is the coating functionality after reaction of the BAG. Adhesion testing after two months of in vitro reaction in a simulated body fluid showed that coating adhesion strength decreased with 10%, but the implant system was still adequate for load-bearing applications.     

Co-enhance bioactive of polymer scaffold with mesoporous silica and nano-hydroxyapatite

Mesoporous silica Santa Barbara Amorphous-15 (SBA15) and nano-hydroxyapatite (nHA) were introduced in poly-l-lactic acid (PLLA) scaffold fabricated by selective laser sintering to co-enhance the bioactivity. On the one hand, the active elements silicon and calcium released respectively by the degradation of SBA15 and nHA were favorable for stimulating cell response. On the other hand, the hydrated silica gel layer derived from SBA15 could adsorb calcium ions released from nHA, thereby co-promoting apatite nucleation and growth. The experimental results showed that the formation of bone-like apatite on the scaffold was accelerated under simulated body fluid, indicating a good biomineralization capacity. Moreover, the scaffold demonstrated a good cell response in promoting the attachment of cell and the expression of alkaline phosphatase activity. Besides, SBA15 and nHA not only improved the hydrophilicity of the scaffold (the water contact angle changed from 107.4° to 57.8°), but also retarded the pH reduction by neutralizing the acidic hydrolysate of PLLA. These results indicated that the PLLA-SBA15-nHA scaffold may be potential candidates for bone repair.