UHMWPE髋臼的厚度对摩擦磨损的影响研究

人工关节中的髋臼大多采用耐磨损性能非常优良的超高分子量聚乙烯（UHMWPE）制作。但仍然产生部分超细磨屑造成骨溶解致使髋臼出现无菌松动。为了了解髋臼的磨损机理，尽量减少磨屑的产生，本研究用美国的ABAQUS有限元软件，对髋臼的厚度与应力，应变关系进行了计算，从应力与磨损之间关系入手，知道了超高分子量聚乙烯髋臼厚度对髋臼摩擦磨损的影响，分析了髋臼磨损机理，为合理设计人工关节提供了理论依据。     

人工关节改性材料的生物摩擦学研究

目的　研究不同人工关节材料的改性技术及生物摩擦学性能,为新型人工关节设计提供可靠的技术与理论基础。方法　选用表面渗碳、微弧氧化和氮离子注入技术对钛合金表面进行改性,以提高其耐磨损性能;超高分子量聚乙烯则采用填充改性技术,制备了UHMWPE/BHA、UHMWPE/NC和UHMWPE/VE复合材料,通过提高UHMWPE关节假体的承载能力和蠕变抗力,降低其磨损率;以聚乙烯醇（PVA）为基体材料,选用纳米羟基磷灰石（HA）为增强剂,制备了PVA/HA复合仿生人工软骨材料,考察了其摩擦学特性。结果　(1) 钛合金的表面改性可获得结合性能良好的表面陶瓷层,可有效提高钛合金的耐磨损性能。（2）超高分子量聚乙烯的填充改性,可获得耐磨损性能良好的关节复合材料,有效减少超高分子量聚乙烯磨损颗粒的产生并降低其磨损颗粒引起的生物学反应     

滚动式人工膝关节设计

针对人工关节中超高分子量聚乙烯(UHMWPE)磨粒导致的骨吸收、骨溶解及由此引起的假体远期松动问题,提出一种滚动式膝关节假体设计。这种膝关节假体利用金属—陶瓷滚动摩擦副代替UHMWPE-金属滑动摩擦副,通过降低膝关节伸屈运动时的摩擦阻力和假体—骨界面间的应力,从而减少磨屑产生,降低假体远期松动的可能性。     

人工关节材料性能与运动性关节软骨损伤

背景：人工关节从开始设计到临床应用已经经历了近一个世纪的历史,人工关节的先导为人工髋关节,随着在临床上的技术应用不断娴熟,推动了腕关节、肩关节、膝关节等人工关节的设计、应用及改进。目的：总结运动性关节损伤中人工关节材料的应用进展及性能特征。方法：由第一作者检索1980至2015年PubMed数据库(http://www.ncbi.nlm.nih.gov/PubMed)、万方数据库(http://wanfangdata.com.cn/)及CNKI中国期刊全文数据库(http://www.cnki.net/),以“sports;cartilage injury; Artificial Joint”为英文检索词,“运动,关节软骨损伤,人工关节”为中文检索词,对目前国内外人工关节的研究资料进行了分析和归纳,逐一介绍并分析了国内外常用的人工关节材料,并从材料科学的角度分析了各种材料在应用时的优劣,对目前常用人工关节的表面处理方法作了阐述,并从发展的角度指出了人工关节的研究方向。结果与结论：钛合金的表面改性可获得结合性能良好的表面陶瓷层,可有效提高钛合金的耐磨损性能。超高分子量聚乙烯的填充改性,可获得耐磨损性能良好的关节复合材料,有效减少超高分子量聚乙烯磨损颗粒的产生并降低其磨损颗粒引起的生物学反应。陶瓷人工关节的进一步研究与完善将是未来人工关节的发展方向。  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     

预损伤与改良传代体外培养许旺细胞的比较

背景：通过组织工程方法构建神经桥接体修复神经损伤,需要大量纯化体外培养的许旺细胞。 目的：对比观察预损伤法和改良传代法获取许旺细胞的纯度与质量。 方法：①预损伤法：预损伤SD乳鼠坐骨神经,3 d后取出坐骨神经,分离神经外膜,用胰酶、胶原酶消化,差速贴壁除去成纤维细胞,接种培养。②改良传代法：直接获取SD乳鼠坐骨神经,分离神经外膜,运用双酶消化法结合单酶消化法进行许旺细胞原代培养,5~7 d后采用单酶快速消化离心法行传代培养,同时纯化许旺细胞。 结果与结论：预损伤法和改良传代法体外培养的许旺细胞纯度均达95%以上,两种方法获得的许旺细胞纯度差异无显著性意义(P > 0.05)。两种方法获取的许旺细胞形态正常,数量及纯度高,增殖旺盛,说明预损伤法和改良传代法都是体外获取高质量与高纯度许旺细胞的理想方法。     

改良酶消化法分离培养人乳牙牙髓干细胞

背景：乳牙牙髓干细胞具有极强的增殖活力,可以在短期内获得组织工程需要的细胞量。 目的：比较传统酶消化法和改良酶消化法获取人乳牙牙髓干细胞的成功率及生物学特性。 方法：取无龋滞留乳切牙12 颗,随机数字表法均分为两组,分别应用传统酶消化法和改良酶消化法分离获取乳牙牙髓细胞,在不同代次细胞中检测细胞扩增天数、收获量、生长曲线、倍增时间、克隆形成率、细胞表面特异标记物STRO-1、CD146、CD34 和CD45 的表达。细胞成骨、成脂诱导分化能力及通过检测碱性磷酸酶和牙本质涎蛋白表达水平,判定细胞牙向分化潜能。 结果与结论：两组细胞生长曲线,扩增天数、细胞收获量及细胞倍增时间相比,差异有显著性意义(P <0.05);牙向分化实验结果显示,改良酶消化法碱性磷酸酶和牙本质涎蛋白较传统酶消化法和对照组而言呈强阳性表达。然而,两组在克隆形成率、细胞表面特异标记物及多项诱导分化等方面差异无显著性意义(P > 0.05)。说明改良酶消化法与传统酶消法相比,可在较短时间内完成同源乳牙牙髓干细胞体外扩增培养,可为牙齿再生治疗提供高质量种子细胞,是乳牙牙髓干细胞体外培养的可靠方法。     

犬骨骼肌成肌细胞体外分离、纯化及培养方法改良探索

目的:探讨犬骨骼肌成肌细胞(SkMs)体外分离、纯化及培养方法的改良并研究其生物学特性.方法:采用机械分离结合Ⅱ型胶原酶、中性蛋白酶双酶一步消化法分离犬骨骼肌成肌细胞,经差速贴壁法纯化后,在骨骼肌细胞生长培养基(SKGM)中进行原代和传代培养,免疫细胞化学染色鉴定.结果:改良后的培养方法适于获取犬骨骼肌成肌细胞,SKGM培养基适于犬骨骼肌成肌细胞的体外培养.SkMs在细胞密集或低血清分化培养基作用下可融合成肌管.结蛋白(desmin)单克隆抗体(mAb)细胞化学染色鉴定SkMs呈阳性,纯度在90%以上.结论:通过改良后的双酶一步消化法获得的SkMs在合适的培养条件下能够增殖、分化并保持其生物学特性,为其在基因治疗和组织工程中的应用奠定了基础.     

氧化铝陶瓷在髋关节置换领域中的应用

今天,高技术陶瓷已经普遍应用于人们的生活、工 作和科技领域,尽管它往往不被肉眼看到,但是其作用 却是不可替代的。随着现代人工关节置换术在临床取得 的成功,关节界面磨损以及其磨屑诱发的骨溶解随之成 为制约人工关节假体长期生存的主要原因。由此,努力 降低关节磨屑的产生并寻找低磨损率的界面材料已成为 人工关节材料学研究领域里的重要课题。陶瓷球头和陶 瓷衬的使用可以显著降低磨损进而有效地改善假体生存     

载紫杉醇聚乳酸聚乙醇酸共聚物纳米粒抑制人肝癌细胞HepG2的作用

背景：临床上应用的紫杉醇注射剂毒性大,过敏反应发生率高。 目的：研制载紫杉醇聚乳酸聚乙醇酸共聚物纳米粒,观察其对人肝癌细胞HepG2的抑制及诱导细胞凋亡的作用。 方法：采用MTT法检测0,3.125,6.25,12.5,25,50,100 mg/L载紫杉醇聚乳酸聚乙醇酸共聚物纳米粒子或紫杉醇作用后人肝癌细胞HepG2的生长;观察25 mg/L载紫杉醇聚乳酸聚乙醇酸共聚物纳米粒子或紫杉醇作用后人肝癌细胞HepG2的形态变化,并观察0,12.5,25,50 mg/L载紫杉醇聚乳酸聚乙醇酸共聚物纳米粒子作用后细胞的凋亡情况。 结果与结论：在3.125-100 mg/L质量浓度范围内,载紫杉醇聚乳酸聚乙醇酸共聚物纳米粒子与紫杉醇均能明显抑制HepG2细胞的生长,且载紫杉醇聚乳酸聚乙醇酸共聚物纳米粒子显示出明显的缓释作用,随着作用时间的增加其抑制率显著增加,72 h时抑制效果最好,但紫杉醇此现象不明显。载紫杉醇聚乳酸聚乙醇酸共聚物纳米粒子或紫杉醇作用后,细胞出现典型的凋亡形态,且随着载紫杉醇聚乳酸聚乙醇酸共聚物纳米粒子作用时间的增加这一现象更加典型;12.5,25,50 mg/L载紫杉醇聚乳酸聚乙醇酸共聚物纳米粒子可明显诱导细胞凋亡,且有明显的量效和时效关系,质量浓度越高、时间越长效果越明显。     

犬关节软骨细胞的体外分离与培养

背景：自1967年Manning等提出的通过胰蛋白酶和细菌胶原酶联合消化法分离软骨细胞以来,软骨细胞的体外分离培养研究较多,但目前尚无统一标准。 目的：研究犬关节软骨细胞在体外分离以及培养的条件,寻求体外扩增软骨细胞较简便、可行、高效的实验方法。 方法：取3周龄幼犬关节软骨组织,应用胰酶、胶原酶制定8种消化方法获取软骨细胞,对比不同方法所获取细胞数量及细胞成活率,分离细胞进行原代及传代培养,观察各代软骨细胞形态。 结果与结论：在体外分离犬关节软骨细胞的各种方法中,单纯应用Ⅱ型胶原酶消化法获得的软骨细胞数最多,细胞成活率最高。软骨细胞可以通过体外培养获得扩增,并且维持良好的细胞形态及表型,但仅限于5代以内。     

Comparison of three joint simulator wear debris isolation techniques: acid digestion, base digestion, and enzyme cleavage

Quantification of ultrahigh molecular weight polyethylene (UHMWPE) wear debris remains a challenging task in orthopedic device analysis. Currently, the weight loss method is the only accepted practice for quantifying the amount of wear generated from a PE component. This technique utilizes loaded soak controls and weight differences to account for polymeric material lost through wear mechanisms. This method enables the determination of the amount of wear in the orthopedic device, but it provides no information about debris particulate size distribution. In order to shed light on wear mechanisms, information about the wear debris and its size distribution is necessary. To date, particulate isolation has been performed using the base digestion technique. The method uses a strong base, ultracentrifugation, and filtration to digest serum constituents and to isolate PE debris from sera. It should be noted that particulate isolation methods provide valuable information about particulate size distribution and may elucidate the mechanisms of wear associated with polymeric orthopedic implants; however, these techniques do not yet provide a direct measure of the amount of wear. The aim of this study is to present alternative approaches to wear particle isolation for analysis of polymer wear in total joint replacements without recourse to ultracentrifugation. Three polymer wear debris isolation techniques (the base method, an acid treatment, and an enzymatic digestion technique) are compared for effectiveness in simulator studies. A requirement of each technique is that the wear particulate must be completely devoid of serum proteins in order to effectively image and count these particles. In all methods the isolation is performed through filtration and chemical treatment. Subsequently, the isolated polymer particles are imaged using scanning electron microscopy and quantified with digital image analysis. The results from this study clearly show that isolation can be performed without the use of ultracentrifugation and that these methods provide a viable option for wear debris analysis.     

Quantitative analysis of ultrahigh molecular weight polyethylene (UHMWPE) wear debris associated with total knee replacements

The size and morphology of particulate wear debris retrieved from tissues around 18 failed total knee replacements (TKR) were characterized. Interfacial membranes from nine cemented and nine uncemented TKR were harvested from below the tibial components during revision surgery. Wear debris were extracted using papain and potassium hydroxide digestion. Ultrahigh molecular weight polyethylene (UHMWPE) particles from around cemented or uncemented TKR were similar in size and morphology. The mean size was 1.7 +/- 0. 7 microm with a range of 0.1-18 microm. Thirty-six percent of the particles were less than 1 microm and 90% were less than 3 microm. Morphologically the particles were predominantly spherical with occasional fibrillar attachments and flakes. Particles from TKR were greater than threefold larger than previously characterized particles from total hip replacements, which were 0.5 microm in mean size. Differences in joint conformity and wear patterns between the hip and knee articulations may explain the disparity in size of the wear debris. Since particle size represents an important variable influencing the magnitude of the biological response, it is possible that in vivo the larger TKR debris results in a diminished mediator release, which in turn may account for the lower incidence of osteolysis and aseptic loosening in some designs of TKR.     

The influence of molecular weight, crosslinking and counterface roughness on TNF-alpha production by macrophages in response to ultra high molecular weight polyethylene particles

The response of murine macrophages to clinically relevant polyethylene wear particles generated from different polyethylenes at various time points and volumetric doses in vitro was evaluated. Clinically relevant ultra high molecular weight polyethylene (UHMWPE) wear debris was generated in vitro in a lubricant of RPMI 1640 supplemented with 25% (v/v) foetal calf serum using a multi-directional pin-on-plate wear rig under sterile conditions. Wear debris was cultured with C3H murine peritoneal macrophages at various particle volume (microm(3)): cell number ratios. The secretion of TNF-alpha was determined by ELISA. Initially the effect of molecular weight of UHMWPE was considered. Higher molecular weight GUR415HP was shown to have a lower wear rate than the lower molecular weight GUR1120, however a greater volume of the wear debris produced by the high molecular weight GUR415HP was in the 0.1-1.0 microm size range. Wear debris from GUR415HP produced significant levels of TNF-alpha at a concentration of 1 microm(3)/cell while at least 10 microm(3)/cell of GUR1120 wear debris per cell was needed to produce significant levels of TNF-alpha. Secondly the effects of crosslinking GUR1050 was examined when worn against a scratched counterface. The wear rate of the material was shown to decrease as the level of crosslinking increased. However the materials crosslinked with 5 and 10 Mrad of gamma irradiation produced higher percentages of 0.1-1.0 microm size wear particles than the non-crosslinked material. While the crosslinked material was able to stimulate cells to produce significantly elevated TNF-alpha levels at a particle concentration of just 0.1 microm(3)/cell only concentrations of 10 microm(3)/cell and above of the non-crosslinked wear debris were stimulatory. When the counterface was changed from scratched to smooth the wear rate for all three GUR1050 materials was further reduced. For the first time nanometre size wear particles were observed from polyethylene which reduced the percentage mass of debris in the 0.1-1.0 microm size range. For all three materials on the smooth counterface only concentrations of 50 microm(3)/cell and above were stimulatory. This study has demonstrated that molecular weight, crosslinking and counterface roughness are important factors in determining the biological activity of polyethylene.     

维生素E稳定型交联超高分子量聚乙烯在骨关节置换中的研究进展

BACKGROUND: As the latest generation of ultrahigh molecular weight polyethylene, vitamin E-stabilized ultrahigh molecular weight polyethylene has been widely put into use of various kinds of joint replacement. However, wear debris and osteolysis caused by that are still the vital factor influencing the clinical curative effect.      

Quantitative analysis of wear and wear debris from metal-on-metal hip prostheses tested in a physiological hip joint simulator

Osteolysis and loosening of artificial joints caused by UHMWPE wear debris has prompted renewed interest in metal-on-metal (MOM) hip prostheses. This study investigated the wear and wear debris morphology generated by MOM prostheses in a physiological anatomical hip simulator for different carbon content cobalt chrome alloys. The low carbon pairings demonstrated significantly higher "bedding in" and steady state wear rates than the mixed and high carbon pairings. The in vitro wear rates reported here were up to one or two orders of magnitude lower than the clinical wear rates for first-generation MOM hip prostheses. Two methods for characterising the metal wear debris were developed, involving digestion, scanning electron microscopy and transmission electron microscopy. The metal wear particles characterised by the two methods were similar in size, 25-36 nm, and comparable to particles isolated from periprosthetic tissues from first and second-generation MOM hip prostheses. Due to the small size of the metal particles, the number of particles generated per year for MOM prostheses in vitro was estimated to be up to 100 times higher than the number of polyethylene particles generated per year in vivo. The volumetric wear rates were affected by the carbon content of the cobalt chrome alloy and the material combinations used. However, particle size and morphology was not affected by method of particle characterisation, the carbon content of the alloy or material combination.     

Microwear phenomena of ultrahigh molecular weight polyethylene cups and debris morphology related to gamma radiation dose in simulator study

Ultrahigh molecular weight polyethylene (PE) cups with 0, 2.5, 50, 100, and 150 Mrad radiation treatments were run in a hip simulator for comparison of the microwear phenomena on the cup surfaces with the corresponding debris morphology. In general, the size and frequency of the PE surface fibrils and the size of the retrieved PE debris decreased with increasing radiation dose. The fibril size and shape on the cup surfaces were well correlated with the radiation dose. The fibrillar shape and size were found to be proportional to the square root of the radiation dose. However, the trend for size and shape factors of the wear debris related to the radiation dose was weak at best. Thus, the morphology of the PE fibrils on the cup surfaces was more sensitive to variations in the radiation dose than the actual wear debris. The wear response appeared to be a three-step process, which was dependent on the formation of surface nodules or ripples, the teasing out of surface fibrils, and the toughness of the PE matrix in releasing a wear fibril to form a debris particle. The tougher PE became with increasing radiation dose, the harder it was for the PE fibrils to break out into wear particles.     

Opsonization of polyethylene wear particles regulates macrophage and osteoblast responses in vitro

The cellular reaction to wear debris may result in the failure of an artificial joint's fixation to the skeleton. The influence of debris opsinization on cell activity has received little attention. This study seeks to establish whether different proteinaceous culture environments may invoke variant cellular responses to debris challenge. Consideration of the zeta potential of a low density polyethylene particle group and an ex vitro ultrahigh molecular weight polyethylene particle group revealed that the nature of the protein adsorbants is related to the concentration of the proteins in solution. Furthermore, the composition of the adsorbed layer was shown to vary with the spectra of proteins in solution. In standard cell culture conditions zeta potential approached zero, indicating the high probability of particle agglomeration. Cell challenge studies with U937 macrophages showed that BSA and FCS protein adsorption mediated increased cell adhesion, while bovine IgG showed little change over control values. No changes in behavior of osteoblastic cells were observed in similar experiments.     

A quantitative study of the tissue reaction and its relationship to debris production from a joint implant.

An attempt has been made to refine the quantitative evaluation of the tissue response to a prosthesis using the goat hip as an experimental model. Total joint replacement was performed in six goats; in three the cup was made of conventional ultrahigh molecular weight polyethylene and in three a new silane cross-linked ultrahigh molecular weight polyethylene was used. The pseudocapsule of the hips was examined histologically at 15, 19 and 24 months following surgery. Small and large polyethylene debris were visualized using semi-crossed polars and were counted. Giant cells were counted after staining with toluidine blue as were macrophages which were identified by dense staining after the acid phosphatase reaction. The amount of small birefringent debris was closely related to the number of macrophages in the pseudocapsule. This method of assessment may be helpful in comparing the tissue reaction of different polymers.     

An easy technique to digest and isolate UHMWPE wear particles from a hip joint simulator

The size and morphology of polyethylene wear particles isolated from in vitro tests were analysed in this study. There are some major controversies emerging in the literature that will only be resolved by careful particles analysis. Since it is difficult to identify the factors that affect size and morphology of the wear particles, the goal of this study was to compare four different polymer wear debris isolation techniques (base method and acid treatment) under identical conditions in a hip joint simulator to obtain polyethylene wear particles. We investigated achieving particulate isolation by using a different approach to the one reported in the literature that involved an easier and streamline method of particle debris isolation. The new method, compared to the previous one, used a strong base, normal centrifugation, and filtration to digest the serum constituents thus isolating the polyethylene particle debris from lubricant. In all four methods the isolation involved some or all of the following steps: density gradient separation, centrifugation or ultracentrifugation, and washing. However, a requirement for all these techniques was that the lubricant had to be devoid of organic compounds in order to effectively image and count the particle debris. The results from these studies clearly show that this new method of particle isolation is easier and more streamlined than the three methods analysed and reported in literature because it did not involve ultracentrifugation and is quicker.