Nano-scale study of the nucleation and growth of calcium phosphate coating on titanium implants

The nucleation and growth of a calcium phosphate (Ca-P) coating deposited on titanium implants from simulated body fluid was investigated by using atomic force microscopy (AFM) and environmental scanning electron microscopy (ESEM). Forty titanium alloy plates were assigned into two groups. One group with a smooth surface having a maximum roughness R(max) < 0.10 microm (s-Ti6Al4V) and a group with a rough surface with an R(max) < 0.25 microm (r-Ti6Al4V) were used. Titanium samples were immersed in SBF concentrated by five (SBF x 5) from 10 min to 5 h and examined by AFM and ESEM. Scattered Ca-P deposits of approximately 15 nm in diameter appeared after only 10 min of immersion in SBF x 5. These Ca-P deposits grew up to 60-100 nm after 4 h on both s- and r-Ti6Al4V substrates. With increasing immersion time, the packing of Ca-P deposits with size of tens of nanometers in diameter formed larger globules and then a continuous Ca-P film on titanium substrates. A direct contact between the Ca-P coating and the Ti6Al4V surface was observed. The Ca-P coating was composed of nanosized deposits and of an interfacial glassy matrix. This interfacial glassy matrix might ensure the adhesion between the Ca-P coating and the Ti6Al4V substrate. In the case of s-Ti6Al4V substrate, failures within this interfacial glassy matrix were observed overtime. Part of the glassy matrix remained on s-Ti6Al4V while part detached with the Ca-P film. The Ca-P coating detached from the smooth substrate, whereas the Ca-P film extended onto the whole rough titanium surface over time. In the case of r-Ti6Al4V, the Ca-P coating covered evenly the substrate after immersion in SBF x 5 for 5 h. The present study suggested that the heterogeneous nucleation of Ca-P on titanium was immediate and did not depend on the Ti6Al4V surface topography. The further growth and mechanical attachment of the final Ca-P coating strongly depended on the surface, for which a rough topography was beneficial.     

Laser cladding of bioactive glass coatings

Laser cladding by powder injection has been used to produce bioactive glass coatings on titanium alloy (Ti6Al4V) substrates. Bioactive glass compositions alternative to 45S5 Bioglass^® were demonstrated to exhibit a gradual wetting angle–temperature evolution and therefore a more homogeneous deposition of the coating over the substrate was achieved. Among the different compositions studied, the S520 bioactive glass showed smoother wetting angle–temperature behavior and was successfully used as precursor material to produce bioactive coatings. Coatings processed using a Nd:YAG laser presented calcium silicate crystallization at the surface, with a uniform composition along the coating cross-section, and no significant dilution of the titanium alloy was observed. These coatings maintain similar bioactivity to that of the precursor material as demonstrated by immersion in simulated body fluid.     

Surface analysis and biocorrosion properties of nanostructured surface sol-gel coatings on Ti6Al4V titanium alloy implants

Surfaces of biocompatible alloys used as implants play a significant role in their osseointegration. Surface sol-gel processing (SSP), a variant of the bulk sol-gel technique, is a relatively new process to prepare bioreactive nanostructured titanium oxide for thin film coatings. The surface topography, roughness, and composition of sol-gel processed Ti6Al4V titanium alloy coatings was investigated by atomic force microscopy (AFM) and X-ray electron spectroscopy (XPS). This was correlated with corrosion properties, adhesive strength, and bioreactivity in simulated body fluids (SBF). Electroimpedance spectroscopy (EIS) and polarization studies indicated similar advantageous corrosion properties between sol-gel coated and uncoated Ti6Al4V, which was attributed to the stable TiO2 composition, topography, and adhesive strength of the sol-gel coating. In addition, inductive coupled plasma (ICP) and scanning electron microscopy with energy dispersive spectrometry (SEM-EDS) analysis of substrates immersed in SBF revealed higher deposition of calcium and phosphate and low release rates of alloying elements from the sol-gel modified alloys. The equivalent corrosion behavior and the definite increase in nucleation of calcium apatite indicate the potential of the sol-gel coating for enhanced bioimplant applications.     

Biocompatibility of corrosion-resistant zeolite coatings for titanium alloy biomedical implants

Titanium alloy, Ti6Al4V, is widely used in dental and orthopedic implants. Despite its excellent biocompatibility, Ti6Al4V releases toxic Al and V ions into the surrounding tissue after implantation. In addition, the elastic modulus of Ti6Al4V (～110 GPa) is significantly higher than that of bone (10–40 GPa), leading to a modulus mismatch and consequently implant loosening and deosteointegration. Zeolite coatings are proposed to prevent the release of the toxic ions into human tissue and enhance osteointegration by matching the mechanical properties of bone. Zeolite MFI coatings are successfully synthesized on commercially pure titanium and Ti6Al4V for the first time. The coating shows excellent adhesion by incorporating titanium from the substrate within the zeolite framework. Higher corrosion resistance than the bare titanium alloy is observed in 0.856 M NaCl solution at pHs of 7.0 and 1.0. Zeolite coatings eliminate the release of cytotoxic Al and V ions over a 7 day period. Pluripotent mouse embryonic stem cells show higher adhesion and cell proliferation on the three-dimensional zeolite microstructure surface compared with a two-dimensional glass surface, indicating that the zeolite coatings are highly biocompatible.     

In vitro dermal and epidermal cellular response to titanium alloy implants fabricated with electron beam melting

Transdermal osseointegrated prostheses (TOPs) are emerging as an alternative to socket prostheses. Electron beam melting (EBM) is a promising additive manufacturing technology for manufacture of custom, freeform titanium alloy (Ti6Al4V) implants. Skin ongrowth for infection resistance and mechanical stability are critically important to the success of TOP, which can be influenced by material composition and surface characteristics.We assessed viability and proliferation of normal human epidermal keratinocytes (NHEK) and normal human dermal fibroblasts (NHDF) on several Ti6Al4V surfaces: solid polished commercial, solid polished EBM, solid unpolished EBM and porous unpolished EBM. Cell proliferation was evaluated at days 2 and 7 using alamarBlue^® and cell viability was analyzed with a fluorescence-based live–dead assay after 1 week.NHDF and NHEK were viable and proliferated on all Ti6Al4V surfaces. NHDF proliferation was highest on commercial and EBM polished surfaces. NHEK was highest on commercial polished surfaces.All EBM Ti6Al4V discs exhibited an acceptable biocompatibility profile compared to solid Ti6Al4V discs from a commercial source for dermal and epidermal cells. EBM may be considered as an option for fabrication of custom transdermal implants.     

Response of human bone marrow stromal cells to a novel ultra-fine-grained and dispersion-strengthened titanium-based material

A novel titanium-based material, containing no toxic or expensive alloying elements, was compared to the established biomaterials: commercially pure titanium (c.p. Ti) and Ti6Al4V. This material (Ti/1.3HMDS) featured similar hardness, yield strength and better wear resistance than Ti6Al4V, as well as better electrochemical properties at physiological pH 7.4 than c.p. Ti grade 1 of our study. These excellent properties were obtained by utilizing an alternative mechanism to produce a microstructure of very fine titanium silicides and carbides (<100 nm) embedded in an ultra-fine-grained Ti matrix (365 nm). The grain refinement was achieved by high-energy ball milling of Ti powder with 1.3 wt.% of hexamethyldisilane (HMDS). The powder was consolidated by spark plasma sintering at moderate temperatures of 700 °C. The microstructure was investigated by optical and scanning electron microscopy (SEM) and correlated to the mechanical properties. Fluorescence microscopy revealed good adhesion of human mesenchymal stem cells on Ti/1.3HMDS comparable to that on c.p. Ti or Ti6Al4V. Biochemical analysis of lactate dehydrogenase and specific alkaline phosphatase activities of osteogenically induced hMSC exhibited equal proliferation and differentiation rates in all three cases. Thus the new material Ti/1.3HMDS represents a promising alternative to the comparatively weak c.p. Ti and toxic elements containing Ti6Al4V.     

Glass-matrix biocomposites

CaO-SiO(2) base glass-matrix/Ti particle biocomposite coatings on Ti6Al4V substrates have been prepared by means of Vacuum Plasma Spray. The base glass is considered bioactive, because, when soaked in a fluid that simulates the inorganic ion concentration of human plasma (SBF), it develops a bonelike apatite layer on its surface. The aim of this research activity was to toughen this brittle bioactive material and to broaden its biomedical applications. Pure titanium was chosen as toughening phase because of its well-known biocompatibility, and Ti6Al4V alloy as substrate because of both its biocompatibility and its mechanical reliability. At first the composites were prepared as bulk materials, by means of a simple sintering process. Then, by ball-milling the sintered composite, the as-obtained "composite powders" were sprayed by Vacuum Plasma Spray (VPS) on the substrate. By means of Differential Thermal Analysis (DTA) and Differential Scanning Calorimetry (DSC), the characteristic temperatures of the base glasses were determined. The thermal properties of mixtures of glass powders and different vol% Ti particles were studied by means of DTA, DSC, hot-stage microscopy, and dilatometry, with the aim of optimizing the sintering conditions. Both the bulk and the coated samples have been characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), compositional analysis (EDS), Vickers indentations, and leaching tests after soaking in a simulated body fluid (SBF).     

UHMWPE与钛基-TiN-TiC系梯度薄膜材料对磨的生物摩擦磨损特性

为了探索超高分子量聚乙烯（ＵＨＭＷＰＥ）与钛基－ＴｉＮ－ＴｉＣ系梯度薄膜材料组合作为人工关节置换材料的可能性,利用离子注入和等离子体化学气相沉积（ＰＣＶＤ）方法制备了Ｔｉ６Ａ１４Ｖ－ＴｉＮ－ＴｉＣ系梯度薄膜材料。通过摩擦系数和ＵＨＭＷＰＥ磨损失重的测定和用ＳＥＭ对磨损后的ＵＨＭＷＰＥ表面形貌分析,研究了ＵＨＭＷＰＥ与Ｔｉ６Ａ１４Ｖ－ＴｉＮ－ＴｉＣ系梯度薄膜材料摩擦副的生物摩擦磨损特性。研究表明：在     

Nucleation and growth of apatite on chemically treated titanium alloy: an electrochemical impedance spectroscopy study

Bone-like apatite formed on the surface of Ti6Al4V pretreated with NaOH solution after having been immersed in simulated body fluid (SBF), while no apatite formed on the surface of untreated Ti6Al4V. In the present study, electrochemical impedance spectroscopy (EIS) measurement was used to investigate the nucleation and growth of apatite on chemically treated Ti6Al4V immersed in the SBF solution, and the difference between the behaviors of treated and untreated Ti6Al4V. Appropriate equivalent circuit models were constructed to describe the nucleation and growth of apatite, and thin oxide film formed on the surface of untreated Ti6Al4V. It was found that EIS is a useful method for investigating the nucleation and growth of bone-like apatite on Ti6Al4V pretreated with NaOH solution.     

A Ni-free ZrCuFeAlAg bulk metallic glass with potential for biomedical applications

The mechanical properties and biocompatibility of an Ni-free Zr-based bulk metallic glass (BMG) Zr_60.14Cu_22.31Fe_4.85Al_9.7Ag₃ were investigated in detail to evaluate its potential as a biomaterial. The BMG was found to have a low Young’s modulus of 82 ± 1.9 GPa, a high strength of 1720 ± 28 MPa and a high fracture toughness of 94 ± 19 MPa m^1/2, as well as good fatigue strength over 400 MPa. The corrosion behavior of the alloy was investigated in simulated body fluid (SBF) by electrochemical measurements, which indicates that the Zr-based BMG has a better corrosion resistance than pure Zr and Ti6Al4V. X-ray photoelectron spectroscopy analysis revealed that the passive film formed on the BMG surface is enriched in Al- and Zr-oxides, which could account for the good corrosion resistance of the BMG. On the other hand, metal ion release of the BMG in SBF was determined by inductively coupled plasma mass spectrometry after the BMG was immersed in SBF at 37 °C for 30 days, showing a ppb (ng ml^?1) level of metal ion release. The in vitro test via cell culture indicates that the BMG exhibits a cytotoxicity of Grade 0–1, which is as good as Ti6Al4V alloy. Cell adhesion morphological analysis shows that the cells were flattened and well spread out on the surfaces of the BMG, showing that the BMG had good biocompatibility. The combination of good mechanical properties and biocompatibility demonstrates that the Ni-free Zr-based BMG studied in this work is a good candidate for a new type of load-bearing biomedical material.     

Osteoblast response and osseointegration of a Ti–6Al–4V alloy implant incorporating strontium

This study investigated the surface characteristics, in vitro and in vivo biocompatibility of Ti–6Al–4V alloy implants incorporating strontium ions (Sr), produced by hydrothermal treatment using a Sr-containing solution, for future biomedical applications. The surface characteristics were evaluated by scanning electron microscopy, thin-film X-ray diffractometry, X-ray photoelectron spectroscopy, optical profilometry, contact angle and surface energy measurement and inductively coupled plasma-mass spectroscopy (ICP-MS). Human osteoblast-like cell (MG63) attachment, proliferation, alkaline phosphatase (ALP) activity, and quantitative analysis of osteoblastic gene expression on Sr-containing Ti–6Al–4V surfaces were compared with untreated Ti–6Al–4V surfaces. Fifty-six screw implants (28 control and 28 experimental) were placed in the tibiae and femoral condyles of seven New Zealand White rabbits. The osteoconductivity of Sr-containing Ti–6Al–4V implants was evaluated by removal torque testing and histomorphometric analysis after 4 weeks implantation. Hydrothermal treatment produced a crystalline SrTiO₃ layer. ICP-MS analysis showed that Sr ions were released from treated surfaces into the solution. Significant increases in ALP activity (P = 0.000), mRNA expressions of key osteoblast genes (osterix, bone sialoprotein, and osteocalcin), removal torque values (P < 0.05) and bone–implant contact percentages (P < 0.05) in both cortical and cancellous bone were observed for Sr-containing Ti–6Al–4V surfaces. The results indicate that the Sr-containing oxide layer produced by hydrothermal treatment may be effective in improving the osseointegration of Ti–6Al–4V alloy implants by enhancing differentiation of osteoblastic cells, removal torque forces and bone apposition in both cortical and cancellous bone.     

热化学法制备CaTiO3涂层及涂层的生物相容性

背景：钛酸钙(CaTiO₃)作为一种有前途的涂层,可应用于钛基医用植入体表面。 目的：通过一种简单的热化学处理技术,在Ti6Al4V基体上制备均匀的CaTiO₃涂层,同时通过培养成骨细胞观察涂层生物相容性。 方法：通过将Ti6Al4V基体埋于无水硝酸钙(Ca(NO₃)₂)粉末中,并且升高温度;当温度处在Ca(NO₃)2熔点以上时,在Ti6Al4V基体上能够生成一层均匀的CaTiO₃层。同时在热化学处理温度为570 ℃的Ti6Al4V基体材料上进行成骨细胞培养,观察所制备涂层的生物相容性。 结果与结论：该涂层转化只有在(Ca(NO₃)₂)熔点(561 ℃)以上时才会发生,同时随着处理温度的升高,CaTiO₃晶体尺寸随之增大;经过热化学处理后的样品具有良好的生物相容性,对成骨细胞黏附、增殖具有更好的促进作用。该方法简单、有效,所制备的涂层具有良好的生物相容性,有望在钛植入体表面处理中获得应用,以提高金属表面与细胞、组织的相容性。     

Electrochemical behavior of (Ti1−xNbx)5Si3 nanocrystalline films in simulated physiological media

In this paper, (Ti_1−xNb_x)₅Si₃ nanocrystalline films were synthesized and their potential as highly corrosion-resistant coatings for the biomedical alloy Ti–6Al–4V was explored. To assess the electrochemical behavior of the as-deposited films, the samples were immersed in Ringer’s solution open to air at 37 °C. The processes that govern the electrochemical reactions at the film surface were analyzed using a combination of complementary electrochemical measurement techniques such as potentiodynamic polarization, electrochemical impedance spectroscopy and Mott–Schottky analysis. The results show that the (Ti_1−xNb_x)₅Si₃ nanocrystalline films offer Ti–6Al–4V a strong shield from corrosive attack and the addition of Nb in the films greatly enhances their resistance to corrosion, and in so doing, minimizes metal ion release. Collectively, our data suggest that (Ti_1−xNb_x)₅Si₃ nanocrystalline films as supreme coatings with anti-corrosive properties have potential to improve the performance and extend the service life of orthopedic and cochlear implants.     

Laser Sintered Porous Ti–6Al–4V Implants Stimulate Vertical Bone Growth

The objective of this study was to examine the ability of 3D implants with trabecular-bone-inspired porosity and micro-/nano-rough surfaces to enhance vertical bone ingrowth. Porous Ti–6Al–4V constructs were fabricated via laser-sintering and processed to obtain micro-/nano-rough surfaces. Male and female human osteoblasts were seeded on constructs to analyze cell morphology and response. Implants were then placed on rat calvaria for 10 weeks to assess vertical bone ingrowth, mechanical stability and osseointegration. All osteoblasts showed higher levels of osteocalcin, osteoprotegerin, vascular endothelial growth factor and bone morphogenetic protein 2 on porous constructs compared to solid laser-sintered controls. Porous implants placed in vivo resulted in an average of 3.1 ± 0.6 mm³ vertical bone growth and osseointegration within implant pores and had significantly higher pull-out strength values than solid implants. New bone formation and pull-out strength was not improved with the addition of demineralized bone matrix putty. Scanning electron images and histological results corroborated vertical bone growth. This study indicates that Ti–6Al–4V implants fabricated by additive manufacturing to have porosity based on trabecular bone and post-build processing to have micro-/nano-surface roughness can support vertical bone growth in vivo, and suggests that these implants may be used clinically to increase osseointegration in challenging patient cases.     

In vitro short-term platelet adhesion on various metals

The in vitro short-term platelet adhesion on various metals, as accelerated by the addition of Ca²⁺, was evaluated in this study. Metals used for medical devices [an austenitic stainless steel, a cobalt (Co)-chromium (Cr)-molybdenum (Mo) alloy, a titanium (Ti)-6 aluminum (Al)-4 vanadium (V) alloy, a Ti-6Al-7 niobium (Nb) alloy, a Tinickel (Ni) alloy, and commercially pure Ti] were immersed into a platelet-rich plasma solution for 5 or 20 min, and platelet adhesion and aggregation on the surfaces were observed using a scanning electron microscope. The platelet adhesion level on each metal after 5 min of immersion in a platelet-rich plasma solution was the smallest in this order: stainless steel ≤ Co-Cr-Mo alloy < Ti-6Al-4V alloy < Ti-6Al-7Nb alloy < Ti-Ni alloy = Ti. The levels after 5 min of immersion were almost the same as those after 20 min of immersion. Platelet adhesion was minimal on stainless steel and Co-Cr-Mo alloy, which have a Cr₂O₃-containing passive surface oxide film, but was accelerated on Ti and Ti alloys having a TiO₂-contanining film. A Cr₂O₃-containing oxide film has a lower relative permittivity than a TiO₂-contanining film; it thus supports a larger electrostatic force than the latter, adsorbs more albumins, which work as inhibitory proteins, and inhibits platelet aggregation. Therefore, platelet adhesion and aggregation are controlled by the composition of the surface oxide film on a metal due to the relative permittivity of the metal, which influences the amount of adsorbed proteins.     

Biological reaction to alumina,zirconia, titanium and polyethylene particles implanted onto murine calvaria

Periprosthetic osteolysis is a serious problem that limits long-term survival of total hip arthroplasty. Ceramics have been introduced as a joint surface material to reduce osteolysis due to wear particles. The aim of this study is to investigate the biological reaction of ceramic particles on murine calvarial bone, in comparison with polyethylene and titanium particles. Sixty CL/BL6 mice were divided into five groups according to the materials implanted onto the murine calvariae: control, Al(2)O(3), ZrO(2), high-density polyethylene (HDP) and Ti6Al4V. One week after the implantation, each calvarial tissue was dissected and the release of proinflammatory mediators (IL-1beta, IL-6, TNF-alpha) and bone resorption were assessed. The particles of HDP and Ti6Al4V induced three and two times larger osteolytic lesions than the control, respectively. The levels of IL-1beta and IL-6 were significantly elevated in the medium subcultured with the calvariae of HDP and Ti6Al4V groups. Any particle type did not increase the levels of TNF-alpha. There were no significant differences observed in the levels of proinflammatory mediators or osteolytic area among Al(2)O(3), ZrO(2) and control groups. The inflammatory response and bone resorption induced by ceramic particles were much smaller than those induced by HDP and Ti6Al4V. These biological features suggest the biocompatibility of ceramics as a joint surface material for artificial joints.     

Mesenchymal stem cell adhesion and spreading on microwave plasma-nitrided titanium alloy

Improved methods to increase surface hardness of metallic biomedical implants are being developed in an effort to minimize the formation of wear debris particles that cause local pain and inflammation. However, for many implant surface treatments, there is a risk of film delamination due to the mismatch of mechanical properties between the hard surface and the softer underlying metal. In this article, we describe the surface modification of titanium alloy (Ti-6Al-4V), using microwave plasma chemical vapor deposition to induce titanium nitride formation by nitrogen diffusion. The result is a gradual transition from a titanium nitride surface to the bulk titanium alloy, without a sharp interface that could otherwise lead to delamination. We demonstrate that vitronectin adsorption, as well as the adhesion and spreading of human mesenchymal stem cells to plasma-nitrided titanium is equivalent to that of Ti-6Al-4V, while hardness is improved 3- to 4-fold. These in vitro results suggest that the plasma nitriding technique has the potential to reduce wear, and the resulting debris particle release, of biomedical implants without compromising osseointegration; thus, minimizing the possibility of implant loosening over time.     

Impacts of trace carbon on the microstructure of as-sintered biomedical Ti–15Mo alloy and reassessment of the maximum carbon limit

The formation of grain boundary (GB) brittle carbides with a complex three-dimensional (3-D) morphology can be detrimental to both the fatigue properties and corrosion resistance of a biomedical titanium alloy. A detailed microscopic study has been performed on an as-sintered biomedical Ti–15Mo (in wt.%) alloy containing 0.032 wt.% C. A noticeable presence of a carbon-enriched phase has been observed along the GB, although the carbon content is well below the maximum carbon limit of 0.1 wt.% specified by ASTM Standard F2066. Transmission electron microscopy (TEM) identified that the carbon-enriched phase is face-centred cubic Ti₂C. 3-D tomography reconstruction revealed that the Ti₂C structure has morphology similar to primary α-Ti. Nanoindentation confirmed the high hardness and high Young’s modulus of the GB Ti₂C phase. To avoid GB carbide formation in Ti–15Mo, the carbon content should be limited to 0.006 wt.% by Thermo-Calc predictions. Similar analyses and characterization of the carbide formation in biomedical unalloyed Ti, Ti–6Al–4V and Ti–16Nb have also been performed.     

In situ cell culture monitoring on a Ti–6Al–4V surface by electrochemical techniques

In this work, the in situ interaction between Ti–6Al–4V alloy and osteoblastic cells has been studied by electrochemical techniques as a function of time. The interaction has been monitored for cell adhesion and growth of human osteoblastic Saos-2 cells on Ti–6Al–4V samples. The study has been carried out by electrochemical techniques, e.g., studying the evolution of corrosion potential with exposure time and by electrochemical impedance spectroscopy. The impedance results have been analyzed by using different equivalent circuit models that simulate the interface state at each testing time. The adhesion of the osteoblastic cells on the Ti–6Al–4V alloy leads to surface areas with different cell coverage rates, thus showing the different responses in the impedance diagrams with time. The effect of the cells on the electrochemical response of Ti–6Al–4V alloy is clearly seen after 4 days of testing, in which two isolated and well-differentiated time constants are clearly observed. One of these is associated with the presence of the cells and the other with a passive film on the Ti–6Al–4V alloy. After 7 days of culture, the system is governed by a resistive component over a wide frequency range which is associated with an increase in the cell coverage rate on the surface due to the extracellular matrix.     

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