Evaluation of mechanical properties and biological response of an alumina-forming Ni-free ferritic alloy

PM 2000 is a Ni-free oxide dispersion strengthened Fe-20Cr-5Al alloy able to develop a fine, dense and tightly adherent alpha-alumina scale during high-temperature oxidation. Despite the high temperature involved during thermal oxidation (1100 degrees C), microstructural changes in the candidate material, a hot rolled product, hardly occurs. Consequently, the good mechanical properties of the as-received material are not significantly affected. Moreover, due to the high compressive residual stresses at the alumina scale, an increase in the fatigue limit from 500 to 530 MPa is observed. Such stresses also account for the high capability of the coating/metal system to withstand more than 1% tensile deformation without cracking. The biocompatibility of the alloy was assessed in comparison to commercial alumina. Saos-2 osteoblast-like cells were either challenged with PM 2000 particles, or seeded onto PM 2000 (with and without scale) solid samples. Viability, growth, and ALP release from cells were assessed after 3 or 7 days, while mineralization was checked at 18 days. This study has demonstrated that PM 2000 with and without scale are capable of supporting in vitro growth and function of osteoblast-like cells over a period of 18 days. Results from this study suggest that the resulting alumina/alloy system combines the good mechanical properties of the alloy with the superior biocompatibility of the alpha-alumina, for which there is very good clinical experience.     

Quantitative assessment of the response of osteoblast- and macrophage-like cells to particles of Ni-free Fe-base alloys

In the present study, the effect of mechanically alloyed particles of new FeAlCr alloys developed for potential applications as surgical implants has been tested on osteoblast- and macrophage-like cells and compared to particles of the Ti6Al4V alloy, for which there is a good clinical experience. After microstructural characterisation of the particles, cells were cultured with particles for 24-48 h using three different concentrations of particles, and the response of cells was quantified by assessment of viability, proliferation, and morphology. Mineralisation by osteoblasts was verified after 21 days. The amount of aluminium and chromium ions in the culture medium of macrophages was measured by graphite furnace atomic absorption and phagocytosis of particles assessed by light microscopy. Viability and proliferation of osteoblast- and macrophage-like cells were substantially unaffected by the presence of particles of the new alloys, which were phagocytosed according to their size. Aluminium and chromium ions were released in the culture medium, but no direct correlation with the cell behaviour was found. In vitro mineralisation was achieved by osteoblasts in due time. The new alloys are well tolerated in in vitro systems, and, due to their chemical and mechanical characteristics, they are under development for surgical implants.     

氟处理AZ31B生物可降解镁合金材料的细胞相容性*

背景：镁及镁合金作为新型可降解植入材料,具有优异的生物相容性和综合力学性能,但是由于镁及镁合金较差的耐蚀性能,影响到其在临床上的应用。表面氟化处理的AZ31B镁合金是否具有良好的生物相容性尚不清楚。 目的：以诱导的人骨髓间充质干细胞作为检测细胞,评价不同表面氟处理的镁合金材料的细胞相容性。 方法：以诱导的人骨髓间充质干细胞作为检测细胞,取未经氟处理及不同氟处理时间的镁合金材料浸提液进行体外细胞相容性实验,评价不同氟处理的镁合金AZ31B材料的生物相容性。 结果与结论：经氟处理镁合金AZ31B材料与未经氟处理镁合金AZ31B材料相比能显著提高细胞存活率,细胞毒性分级1级,对细胞生长基本无毒性作用。提示经氟处理镁     

Cytocompatibility of two coating materials, amorphous alumina and silicon carbide, using human differentiated cell cultures.

The cytocompatibility of two coating materials, amorphous alumina and silicon carbide deposited by radio-frequency sputtering, was studied using alveolar bone osteoblasts and gingival fibroblasts from human healthy tissues. Cytocompatibility was assessed at the level of both the basic (attachment, proliferation and cell protein content) and the specific features (intracellular alkaline phosphatase activity and the cytoskeleton) of the cells in direct contact with the coating. Titanium was used as the reference material. The results showed that both silicon carbide and amorphous alumina are cytocompatible for human fibroblasts and osteoblasts, whereas titanium appears the least cytocompatible of all the three substrates. Moreover, the amorphous alumina coating seems slightly bioactive. It seems that these coatings, particularly amorphous alumina, could be used to protect alloys against corrosion, and consequently combine the good mechanical properties of the alloys with the good biocompatibility of the coatings. These coatings seem to perform more suitably than titanium if the strength of the bond between the coating and the underlying alloys is strong enough to give a stable composite material.     

Easy assessment of the biocompatibility of Ni-Ti alloys by in vitro cell culture experiments on a functionally graded Ni-NiTi-Ti material

The biocompatibility of nickel-titanium alloys was investigated by single-culture experiments on functionally graded samples with a stepwise change in composition from pure nickel to pure titanium, including an Ni-Ti shape memory alloy for a 50:50 mixture. This approach permitted a considerable decrease of experimental resources by simultaneously studying a full variation of composition. The results indicate a good biocompatibility for a nickel content up to about 50%. The cells used in the biocompatibility studies comprised osteoblast-like osteosarcoma cells (SAOS-2, MG-63), primary human osteoblasts (HOB), and murine fibroblasts (3T3).     

镍钛形状记忆合金表面改性后的血液相容性

背景：镍钛形状记忆合金植入人体内必需要有很好的生物相容性和生物安全性。 目的：观察分析镍钛形状记忆合金表面改性后对其生物相容性的影响。 方法：将镍钛形状记忆合金随机分为两组,经阴极电沉积法处理的材料为实验组,未经处理的为空白组,通过扫描电镜观察实验组材料表面的变化,并测定材料的溶血率和动态凝血时间。体外培养骨髓基质干细胞,与两组材料复合培养,通过MTT法检测两组材料中细胞存活数量。 结果与结论：镍钛形状记忆合金表面改性后,表面出现由很多的纳米级颗粒紧密聚集形成的Ti-O膜,实验组材料的溶血率下降,凝血时间延长,两组材料与骨髓基质干细胞复合培养第2,4,6天,实验组吸光度比空白组明显增高(P < 0.05)。说明镍钛形状记忆合金经阴极电沉积法表面改性后具有较好的生物相容性和生物安全性。     

人骨髓间充质干细胞检测表面氟化处理镁合金材料的细胞相容性

背景：表面氟化处理的AZ31B镁合金是中科院金属研究所新研制的镁合金,是否具有良好的生物相容性尚不确切。 目的：以人骨髓间充质干细胞作为检测细胞,评价表面氟处理的镁合金材料的细胞相容性。 方法：人骨髓间充质干细胞培养并予以鉴定,将镁合金AZ31B作为对照组,氟处理的镁合金AZ31B材料为实验组。以人骨髓间充质干细胞作为检测细胞,取两组材料浸提液进行体外细胞相容性实验,评价氟处理的镁合金AZ31B材料的生物相容性。 结果与结论：与未经氟处理镁合金AZ31B材料相比,经氟处理镁合金AZ31B材料能显著提高细胞存活率,细胞毒性分级１级,对细胞生长基本无毒性作用。结果表明,经氟处理镁合金AZ31B材料生物相容性优于未经氟处理镁合金AZ31B材料。     

Effects of surface treatment of Ti-6Al-4V titanium alloy on biocompatibility in cultured human umbilical vein endothelial cells

Among the titanium alloys employed as implant materials, the Ti-6Al-4V alloy is still widely used. Ti-6Al-4V titanium alloy samples, in untreated state and subjected to treatments in air by furnace or glow-discharge processes, were put in contact with human umbilical vein endothelial cells (HUVEC) in order to evaluate their effects on biocompatibility. In HUVEC kept for 48 h in the presence of the three sample types neither cell proliferation nor protein content nor lactate dehydrogenase release in the culture medium are affected, while apoptosis is induced after 48- and 96-h contact of the cells with the untreated sample type, and after 96-h contact with the plasma treated one, the furnace treated sample type being ineffective. The expression of two adhesion molecules, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) was also studied. The incubation of HUVEC with the three sample types for 48 or 96 h induces a significant increase in ICAM-1 protein levels, in comparison with control cells, while VCAM-1 expression is not detectable. In the same way, TNF-alpha release in the culture medium, assayed after 48- and 96-h contact of the cells with the three sample types, is significantly higher, in comparison with control, even if the highest values are registered in the presence of the untreated samples. Taken together, these data indicate that, although Ti-6Al-4V alloy samples, and in particular the treated ones, show a good biocompatibility, attention must be given to the first signs of inflammation.     

镁合金作为生物医用植入材料的临床应用

背景：镁合金由于其良好的生物相容性,可降解性等突出优点,在生物植入材料,尤其是作为可降解硬组织植入材料领域展示了良好的应用前景。而过快的降解速度是其投入临床应用亟待解决的关键问题。 目的：对近期相关文献的综合分析归纳,对镁合金作为医用植入材料的优缺点进行了综述,对生物医用镁合金材料研究的最新进展进行了总结。 方法：以“magnesium; magnesium calcium alloy; biodegradable; biomaterials”及“镁;镁钙合金;可降解;生物医用材料”为关键词检索ScienceDirect数据库和中国期刊全文数据库。纳入与镁合金生物医用材料密切相关文献,保留34篇文献做进一步分析。 结果与结论：镁钙及镁钙基合金是未来生物医用植入材料重要的发展方向之一,快速凝固工艺是有效改善镁合金降解速度过快问题的新方法;计算模拟方法应用于镁合金生物材料有可能从微观角度深入理解镁合金用于生物医用植入材料的相关问题;另一方面,国内镁合金生物材料研究急需从基础向临床转化。     

牙科金属材料的组成对细胞毒性影响的研究

选择９种中日常胜的牙科金属和合金材料，其基本组成是Ｎ－Ｃｒ，Ｃｏ－Ｃｒ－Ｍｏ，Ａｇ－Ｐｄ－Ａｕ－Ｃｕ，Ａｇ－Ｚｎ，Ｎｉ－Ｔｉ，Ｎｉ－Ｃｒ－Ｃｏ和Ｃｕ基，用Ｌ－９２９小鼠成纤维细胞，经细胞－金属表面直接接触４８ｈ，对去除刺激因素的细胞，用紫外分光光度仪和扫描电镜进行检测，并在原子吸收光谱仪下定量分析材料渍液中溶出金属元素的成分，物化学组成，溶解元素对细胞毒性的影响。结果表明Ｃｕ基合金因合中存在分别形     

微弧氧化AZ31镁合金的生物相容性

背景：表面改性技术和合金成分的变化都会影响到镁合金的生物特性。 目的：探讨微弧氧化处理AZ31镁合金的生物相容性。 方法：将体外扩增培养的兔第3代骨髓基质细胞接种到未处理AZ31镁合金(镁合金+骨髓基质细胞组)和微弧氧化AZ31镁合金(微弧氧化镁合金+骨髓基质细胞组)材料上,另设骨髓基质细胞组做对照。培养1,3,5,7 d观察细胞形态,细胞生长状况,细胞黏附状况,材料表面状况。 结果与结论：3组细胞形态一致,以梭形为主。镁合金+骨髓基质细胞组中细胞生长状况明显不如微弧氧化镁合金+骨髓基质细胞组和骨髓基质细胞组(P < 0.05)。微弧氧化镁合金+骨髓基质细胞组材料表面有大量的细胞附着,并且生长正常,镁合金+骨髓基质细胞组材料表面没有细胞附着,有明显的裂痕(P < 0.05)。结果证实,微弧氧化处理AZ31镁合金具有良好的生物相容性,有利于细胞的附着和正常生长。     

Tribo-electrochemical characterization of metallic biomaterials for total joint replacement

Knee and hip joint replacement implants involve a sliding contact between the femoral component and the tibial or acetabular component immersed in body fluids, thus making the metallic parts susceptible to tribocorrosion. Micro-motions occur at points of fixation leading to debris and ion release by fretting corrosion. β-Titanium alloys are potential biomaterials for joint prostheses due to their biocompatibility and compatibility with the mechanical properties of bone. The biotribocorrosion behavior of Ti-29Nb-13Ta-4.6Zr was studied in Hank's balanced salt solution at open circuit potential and at an applied potential in the passive region. Reciprocating sliding tribocorrosion tests were carried out against technical grade ultra high molecular weight polyethylene, while fretting corrosion tests were carried out against alumina. The wear of the alloy is insignificant when sliding against polyethylene. However, depassivation does take place, but the tested alloy showed an ability to recover its passive state during sliding. The abrasivity of the alloy depends on the electrochemical conditions of the contact, while the wear of polyethylene proceeds through third body formation and material transfer. Under fretting corrosion conditions recovery of the passive state was also achieved. In a fretting contact wear of the alloy proceeds through plastic deformation of the bulk material and wear resistance depends on the electrochemical conditions.     

Investigation on Tc tuned nano particles of magnetic oxides for hyperthermia applications

Superparamagnetic as well as fine ferrimagnetic particles such as Fe3O4, have been extensively used in magnetic field induced localized hyperthermia for the treatment of cancer. The magnetic materials with Curie temperature (Tc) between 42 and 50 degrees C, with sufficient biocompatibility are the best candidates for effective treatment such that during therapy it acts as in vivo temperature control switch and thus over heating could be avoided. Ultrafine particles of substituted ferrite Co(1-a)Zn(a)Fe2O4 and substituted yttrium-iron garnet Y3Fe(5-x)Al(x)O12 have been prepared through microwave refluxing and citrate-gel route respectively. Single-phase compounds were obtained with particle size below 100 nm. In order to make these magnetic nano particles biocompatible, we have attempted to coat these above said composition by alumina. The coating of alumina was done by hydrolysis method. The coating of hydrous aluminium oxide has been done over the magnetic particles by aging the preformed solid particles in the solution of aluminium sulfate and formamide at elevated temperatures. In vitro study is carried out to verify the innocuousness of coated materials towards cells. In vitro biocompatibility study has been carried out by cell culture method for a period of three days using human WBC cell lines. Study of cell counts and SEM images indicates the cells viability/growth. The in vitro experiments show that the coated materials are biocompatible.     

HA/Mg-Zn合金体内降解及生物相容性的评价

目的观察氟磷灰石﹙FHA﹚涂层镁锌合金在动物体内降解和生物相容性。方法取8只新西兰健康成年大白兔,随机分为2组:氟磷灰石﹙FHA﹚涂层镁锌合金和无涂层镁锌合金。在动物一侧股骨髁使用克氏针钻洞﹙4.5mm×10mm﹚,将FHA/Mg-Zn合金的棒状物﹙4.5mm×10mm﹚植入,同样办法在另一只兔子股骨髁植入大小一样的Mg-Zn合金的棒状物,术后4周取动物心、肝、肾及关节囊,HE染色后观察组织病理学改变,取股骨髁组织切片品红苦味酸染色,观察植入物的降解及新骨的形成。股骨髁行Micro-CT分析。结果 2组材料对动物心、肝、肾及关节囊的组织病理结果均正常。FHA/Mg-Zn合金与周围骨组织紧密接触,周围有大量新骨形成,未见明显降解。Mg-Zn合金明显降解,与周围骨组织形成缝隙,新骨形成较少。结论 FHA/Mg-Zn合金有效控制降解,具有良好生物相容性。     

Toxicity of copper-based dental alloys in cell culture

The biocompatibility of three commercial copper-based dental casting alloys--Duracast MS, Goldent, and Trindium--three experimental copper alloys, and a control gold alloy, Modulay, were investigated. Trindium, Duracast MS, experimental alloys 1 and 2 are aluminum bronzes; Goldent is a hybrid aluminum-brass alloy; and experimental alloy #3 is a high zinc brass alloy. ASTM F813-83 Standard Practice for Direct Contact Cell Culture Evaluation of Materials for Medical Devices, a 3-day direct-contact cell culture regimen and atomic absorption spectroscopy were utilized for evaluating the biocompatibility of these alloys in both Waymouth's and RPMI 1640 complete media. Cellular proliferation assays, using 3H-thymidine uptake, were also conducted in Waymouth's media. In this investigation, only the experimental alloy #3 elicited alterations in morphology and viability of the fibroblast monolayer during the ASTM and 3-day culture tests in either media. Cell cultures exposed to experimental alloy #3 experienced copper concentrations greater than 16.0 ppm in Waymouth's and 10 ppm copper in RPMI 1640 media. Differences in the size of the cytotoxic zone around experimental alloy #3 were also observed, with the larger zone occurring in Waymouth's media. In contrast to the direct cell contact studies, all alloys caused decreases in 3H-thymidine uptake in Waymouth's media at much reduced metal ion concentrations as compared to the controls. Thus, adverse changes in DNA synthesis occurred at much lower copper and zinc concentrations than changes in morphology and viability. Consequently, the assessment of biocompatibility is dependent on the parameters evaluated, and several parameters must be analyzed before a material may be considered biocompatible.     

Integration between a percutaneous implant and the porcine small bowel

Magnesium alloys may potentially be applied as biodegradable metallic materials in cardiovascular stent. However, the high corrosion rate hinders its clinical application. In this study, a new approach was adopted to control the corrosion rate by fabricating a biocompatible micro-arc oxidation/poly-L-lactic acid (MAO/PLLA) composite coating on the magnesium alloy WE42 substrate and the biocompatibility of the modified samples was investigated. The scanning electronic microscope (SEM) images were used to demonstrate the morphology of the samples before and after being submerged in hanks solution for 4 weeks. The degradation was evaluated through the magnesium ions release rate and electrochemical impedance spectroscopy (EIS) test. The biocompatibility of the samples was demonstrated by coagulation time and hemolysis behavior. The result shows that the poly-L-lactic acid (PLLA) effectively improved the corrosion resistance by sealing the microcracks and microholes on the surface of the MAO coating. The modified samples had good compatibility.     

Morphological characterization and in vitro biocompatibility of a porous nickel-titanium alloy

Disks consisting of macroporous nickel-titanium alloy (NiTi, Nitinol, Actipore) are used as implants in clinical surgery, e.g. for fixation of spinal dysfunctions. The morphological properties were studied by scanning electron microscopy (SEM) and by synchrotron radiation-based microtomography (SRmuCT). The composition was studied by X-ray diffractometry (XRD), differential scanning calorimetry (DSC), and energy-dispersive X-ray spectroscopy (EDX). The mechanical properties were studied with temperature-dependent dynamical mechanical analysis (DMA). Studies on the biocompatibility were performed by co-incubation of porous NiTi samples with isolated peripheral blood leukocyte fractions (polymorphonuclear neutrophil granulocytes, PMN; peripheral blood mononuclear leukocytes, PBMC) in comparison with control cultures without NiTi samples. The cell adherence to the NiTi surface was analyzed by fluorescence microscopy and scanning electron microscopy. The activation of adherent leukocytes was analyzed by measurement of the released cytokines using enzyme-linked immunosorbent assay (ELISA). The cytokine response of PMN (analyzed by the release of IL-1ra and IL-8) was not significantly different between cell cultures with or without NiTi. There was a significant increase in the release of IL-1ra (p<0.001), IL-6 (p<0.05), and IL-8 (p<0.05) from PBMC in the presence of NiTi samples. In contrast, the release of TNF-alpha by PBMC was not significantly elevated in the presence of NiTi. IL-2 was released from PBMC only in the range of the lower detection limit in all cell cultures. The material, clearly macroporous with an interconnecting porosity, consists of NiTi (martensite; monoclinic, and austenite; cubic) with small impurities of NiTi2 and possibly NiC(x). The material is not superelastic upon manual compression and shows a good biocompatibility.     

Tissue reaction to ceramic implant material.

The biocompatibility of alumina ceramic was tested by means of macrophage cultures, intraperitoneal (i.p.) and intramuscular (i.m.) application of powdered particles in rats, and by implantation of solid samples in the paravertebral muscles and the condylus femur. No acute cytotoxicity was found in macrophage cultures. The i.p. and i.m. application of powdered particles in the beginning showed a granulocytic reaction, later followed by a histiocytic reaction. Also, the morphological changes in the organs of reticulo histiocytic system (RHS) are shown. In the solid samples implantation, the fibrogenetic stimulus is measured by morphological analysis of the connective tissue membrane around the sample. The importance of the individual cell observation by transmission-electron microscope (TEM) examination is evidenced. The experimental results are compared to the environmental reaction of smaller animal-adapted prostheses and prostheses having been implanted in human patients. Good biocompatibility is confirmed by these investigations; also regarding central position of the macrophages, the environmental reaction due to implant material is shown.     

Ti-Fe-Mo-Mn-Nb-Zr系合金的生物安全性评价

采用体内急性全身性毒性实验、溶血实验、MTT实验 (Tetrazolium- based colorim etric assay)和材料浸渍液培养细胞的形态学观察法实验等对 Ti- Fe- Mo- Mn- Nb- Zr系合金的生物安全性进行了初步的评价。采用 x射线光电子能谱仪 (XPS)分析了合金表面氧化膜成分 ,并用原子发射光谱仪 (ICP)检测了浸渍液中合金元素的种类和浓度。结果显示 :Ti- Fe- Mo- Mn- Nb- Zr系合金表面形成了以 Ti O2 为主的致密氧化膜 ,浸渍液中均存在浓度为0 .2～ 1.0 7mg/ l的 Fe和 0 .16～ 0 .5 mg/ l的 Mn,这种义齿材料有利于补充人体所需的 Fe和 Mn;未见任何急性毒性反应 ;溶血程度为 0 .5 5 8%～ 0 .6 4 2 % ,有良好的血液相容性 ;细胞毒性实验评价级别为 0和 1级 ,无明显的细胞毒性作用 ;倒置相差显微镜观察细胞形态 ,未发现异常。由以上结果可以初步认为 Ti- Fe- Mo- Mn- Nb- Zr系合金是一种理想的生物材料     

九种医用金属材料的生物相容性

作者对九种金属材料:包括四种316L不锈钢,三种钛金属及二种钴铬钼合金材料,采用体外鸡胚股骨培养法和细胞毒性试验法进行了生物相容性评价,并将其中六种材料作了溶血试验,急性毒性试验及热源试验。 实验结果表示:九种金属材料在鸡胚股骨培养及细胞毒性试验中毒性低,其中六种金属材料的急性毒性、溶血及热源试验全部合格。这为筛选出较优良的临床使用材料,提供了一定的依据。