共查询到19条相似文献,搜索用时 187 毫秒
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生物可降解支架是在植入手术后血管修复期间为血管提供一定的支撑作用,然后预期在血管修复完成后一段时间内,通过与体内环境的相互作用转化成无毒性的降解产物被人体所吸收或排出体外。因此,人们对作为可降解支架的金属材料的力学性能、耐腐蚀性、降解特性、生物相容性等都提出了严格的要求。近年来,铁基合金作为可降解金属材料成为生物医学领域新的研究热点。纯铁是人体必需的微量元素之一,且具有优异的力学特性、耐腐蚀性、降解特性、生物性能以及加工成型性,这使得铁基合金作为生物医用可降解材料成为可能。然而,纯铁的降解速率过慢,这是阻碍其作为生物医用金属材料的主要问题之一。合金化在改善铁基材料降解性能的同时也可以改善力学性能,从而提高铁基材料的综合性能。在提高降解速率的同时,铁基材料也应保证足够的力学性能来支撑血管,并且力学性能越好、支架壁越薄、质量越小,则越能缩短降解时间,降解产物越少,对人体的毒性也越小。本文综述了铁基合金作为支架材料的研究现状,以及目前报道的铁锰合金的力学性能、腐蚀降解性能以及体外细胞相容性,并重点介绍了铁锰合金在生物可降解支架方面的研究现状以及需解决的关键问题,同时给出可能的解决方案。 相似文献
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进入21世纪以来,随着材料科学的进步,医用金属植入材料从传统的316L不锈钢、钛合金等惰性金属材料逐渐转向可降解金属材料。可降解金属材料由于其良好的生物相容性和适宜的降解速率,可以在完成植入任务时被人体吸收,无需二次手术将内植物取出,从而引起广泛关注。在过去的10多年里,镁和铁及其合金作为医用可降解金属被广泛研究。锌是人体所必需的营养元素之一,因具有良好的生物相容性和适宜的降解速率,锌基合金在最近几年里成为继镁基和铁基合金之后又一具有广泛应用前景的医用可降解金属。然而,对锌基合金的设计和制备等仍处于初步阶段,还有大量的研究工作需要完成。综述了生物降解锌近年来用于骨科领域的研究进展,重点讨论了锌及其合金的力学性能、生物降解性能和生物相容性以及锌的合金化和制造技术之间的关系。 相似文献
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随着人们医疗观念的转变和材料科学的进步,医用金属植入材料的选择从传统316L不锈钢、钴铬合金、钛合金等惰性金属逐渐转向可降解材料。为了减轻与耐腐蚀支架相关的副作用(即慢性炎症和晚期血栓形成),目前正在开发新一代的生物可吸收支架,支架在完成任务后会被逐渐降解和吸收。目前的可降解金属主要包括镁合金、铁合金和锌合金,铁在动脉中产生大量的氧化产物而镁及其合金又腐蚀得太快。其中,锌合金具有更适宜的降解速度、良好的降解行为和较好的力学性能,基于锌的生物可吸收材料是近年兴起的最具发展潜力的可降解医用金属材料。本文主要介绍了纯锌、锌铜系、锌镁系及其他锌基合金近年来的主要研究进展。 相似文献
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目前可降解血管支架材料包括聚合物、镁合金、铁合金及锌合金,它们的降解特性直接影响其作为血管支架植入后的支撑能力、局部反应和血管修复的预后。聚合物降解时间较易调整、生物相容性较好,但力学性能不足;镁合金的降解存在降解速率快、释氢反应和微环境pH值变化较大的问题;铁合金降解速率太慢;锌合金的降解速率适中,是近年可降解血管内植入材料研究热点。除了材料自身的特性,可降解材料的血管内降解行为还受到环境的离子浓度、酶、pH值和温度等多种因素的影响。综述了目前不同血管内可降解支架材料在模拟体液及动物体内生物降解行为的研究结果,以期为血管内可降解材料研究和产品开发提供参考。 相似文献
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目的 综述可降解材料(光降解材料、生物降解材料和光-生物降解材料)的研究现状,探讨可降解材料在海洋领域的研究进展和未来研究方向。方法 综述各类可降解材料的特性、应用及其降解机理,并从材料降解机理的角度讨论可降解材料在海水中的降解可行性及相应的材料改性方法。结果 由于海水环境存在特殊性,各类可降解材料在海水中的降解性能大幅下降,降解过程受诸多因素影响,为了使材料能在海水环境下降解,针对降解材料改性研究方面提出了建议。结论 可降解材料虽是目前材料领域的研究热点,但可降解材料在海洋领域的应用仍处于起步阶段,因此,开发出具有良好水降解性能的可降解材料是解决海洋污染问题的重点,也是未来研究的难点和热点。 相似文献
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为了防止心血管支架植入后再狭窄的发生,目前采用将抑制平滑肌细胞生长的药物通过高分子载体涂在支架表面.由于支架植入体内后,涂层受到血液冲刷作用.本工作采用可降解高分子材料PLGA作为载体,将PLGA薄膜置于体外循环冲刷装置中,在37℃、pH7.4的Hank's模拟体液、模拟血流冲刷作用下的体外降解,并与静态降解作为对比.采用SEM、GPC、1H-NMR和DSC技术研究了聚合物在降解过程中形貌、分子量及分子量分布、失重率、组成和热性能的变化,并对降解机理进行探讨.与静态降解相比较,在流动体液中,高分子载体表面形貌、失重率以及分子量变化均较慢.上述结果与表面微环境有关. 相似文献
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《材料科学技术学报》2020,(4)
Magnesium alloy coronary stent becomes a hot research topic due to its biodegradable character for avoiding late thrombosis and late restenosis. However, fracture of Mg alloy stent was a common issue after implantation. In this study, 18 drug-eluting biodegradable AZ31 B stents were implanted into porcine coronary arteries to assess its structural integrity, corrosion behavior and microstructure change in vivo.The coronary artery tissue responses to AZ31 B stent implantation were detected by quantitative coronary angiography and optical coherence tomography at the set time periods. In addition, further analyses were focused on the stent structure integrity, corrosion behaviors and the microstructure change of Mg alloy stents after implantation. A large number of fractures on stent struts were observed by high-resolution transmission X-ray tomography clearly. Moreover, degradation products, twins and grain refinement that appeared in Mg alloy stent matrix after implantation were also observed during the study. Inferred from this study, it is shown that the loss of AZ31 B stent structural integrity may be the result of stress concentration, degradation and microstructure change. 相似文献
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Jan Tobias Krüger Kay-Peter Hoyer Anatolii Andreiev Mirko Schaper Carolin Zinn 《Advanced Engineering Materials》2023,25(3):2201008
In medical technology, implants are used to improve the quality of patients’ lives. The development of materials with adapted properties can further increase the benefit of implants. If implants are only needed temporarily, biodegradable materials are beneficial. In this context, iron-based materials are promising due to their biocompatibility and mechanical properties, but the degradation rate needs to be accelerated. Apart from alloying, the creation of noble phases to cause anodic dissolution of the iron-based matrix is promising. Due to its high electrochemical potential, immiscibility with iron, biocompatibility, and antibacterial properties, silver is suited for the creation of such phases. A suitable technology for processing immiscible material combinations is powder-bed-based procedure like laser beam melting. This procedure offers short exposure times to high temperatures and therefore a limited time for diffusion of alloying elements. As the silver phases remain after the dissolution of the iron matrix, a modification is needed to ensure their degradability. Following this strategy, pure iron with 5 wt% of a degradable silver–calcium–lanthanum alloy is processed via laser beam melting. Investigation of the microstructure yields achievement of the intended microstructure and long-term degradation tests indicates an impact on the degradation, but no increased degradation rate. 相似文献
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Anticorrosion and cytocompatibility behavior of MAO/PLLA modified magnesium alloy WE42 总被引:1,自引:0,他引:1
Guo M Cao L Lu P Liu Y Xu X 《Journal of materials science. Materials in medicine》2011,22(7):1735-1740
Recently, biodegradable magnesium alloys have been introduced in the field of cardiovascular stents to avoid the specific
drawbacks of permanent metallic implants. However, the major obstacle of the clinical use of magnesium-based materials is
their rapid corrosion rate. In this paper, a composite micro-arc oxidation/poly-l-lactic acid (MAO/PLLA) coating was fabricated on the surface of the magnesium alloy WE42 to improve its corrosion resistance
and the cytocompatibility of the modified materials was also investigated for safety aim. In our study, the morphology of
materials was analyzed by Scanning electron microscopy. Potentiodynamic polarization was used to evaluate the corrosion behavior
of the samples and corrosion weight loss was used to demonstrate their degradation rate. Furthermore, we applied cytotoxicity
test in testing the cytocompatibility of the modified samples. The results showed that the PLLA coating effectively sealed
the microcracks and micropores on the surface of the MAO coating by physical interlocking to interfere the corrosion ions.
The corrosion rate was decreased and the cyototoxicity test showed that the MAO/PLLA composite coating WE42 had good cytocompatibility. 相似文献
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《Current Opinion in Solid State & Materials Science》2020,24(3):100822
The movement towards the commercialization of biodegradable Fe has been hampered by the perceived slow degradation rate of the metal in physiological environments. The introduction of Fe-Mn alloys offers promise due to its significantly improved biocorrosion rates, excellent biocompatibility, and non-magnetic properties. However, the issue of slow corrosion rates persists in this alloy and its future hinges on addressing this issue. This short review report presents the current approaches to address this problem, the challenges concerning Fe-Mn corrosion, and some future techniques that may improve the degradation rate of Fe-Mn alloys. 相似文献
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In order to improve mechanical and corrosion properties of biodegradable pure Zn,a knowledge-based microstructure design is performed on Zn-Li alloy system composed of hard β-LiZn4 and soft Zn phases.Precipitation and multi-modal grain structure are designed to toughen β-LiZn4 while strengthen Zn,resulting in high strength and high ductility for both the phases.Needle-like secondary Zn precipi-tates form in β-LiZn4,while fine-scale networks of string-like β-LiZn4 precipitates form in Zn with a tri-modal grain structure.As a result,near-eutectic Zn-0.48Li alloy with an outstanding combination of high strength and high ductility has been fabricated through hot-warm rolling,a novel fabrication process to realize the microstructure design.The as-rolled alloy has yield strength (YS) of 246 MPa,the ultimate tensile strength (UTS) of 395 MPa and elongation to failure (EL) of 47 %.Immersion test in simulated body fluid (SBF) for 30 days reveals that Li-rich products form preferentially at initial stage,followed by Zn-rich products with prolonged time.Aqueous insoluble Li2CO3 forms a protective passivation film on the alloy surface,which suppresses the average corrosion rate from 81.2 μm/year at day one down dramatically to 18.2 μm/year at day five.Afterwards,the average corrosion rate increases slightly with decrease of Li2CO3 content,which undulates around the clinical requirements on corrosion resistance(i.e.,20 μm/year) claimed for biodegradable metal stents. 相似文献
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Michael Schinhammer Isabel Gerber Anja C. Hänzi Peter J. Uggowitzer 《Materials science & engineering. C, Materials for biological applications》2013,33(2):782-789
Biodegradable iron-based alloys are potential candidates for application as temporary implant material. This study summarizes the design strategy applied in the development of biodegradable Fe–Mn–C–Pd alloys and describes the key factors which make them suitable for medical applications. The study's in vitro cytotoxicity tests using human umbilical vein endothelial cells revealed acceptable cytocompatibility based on the alloys' eluates. An analysis of the eluates revealed that Fe is predominantly bound in insoluble degradation products, whereas a considerable amount of Mn is in solution. The investigation's results are discussed using dose–response curves for the main alloying elements Fe and Mn. They show that it is mainly Mn which limits the cytocompatibility of the alloys. The study also supplies a summary of the alloying elements' influence on metabolic processes.The results and discussion presented are considered important and instructive for future alloy development. The Fe-based alloys developed show an advantageous combination of microstructural, mechanical and biological properties, which makes them interesting as degradable implant material. 相似文献
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Shengfa Zhu Nan Huang Li Xu Yu Zhang Hengquan Liu Hong Sun Yongxiang Leng 《Materials science & engineering. C, Materials for biological applications》2009,29(5):1589-1592
Pure iron is a candidate material for coronary artery stents because of its biodegradable and nontoxic properties. However the degradation characteristics of pure iron in vivo and in vitro are not yet clear. The purpose of the work described here was to determine the degradation rate of pure iron in vitro and to characterize the interaction of individual corrosion products from biocorrodible iron stents with endothelial cells (ECs) from the adjacent tissue. Pure iron was immersed in simulated body fluids (SBF) solution and the mass loss was measured. The response of human ECs to various concentrations of ferrous ions was investigated using WST-8 assay. The results demonstrate that the mean degradation rate of iron in vitro is about 20.4 μg/(cm2 h). The lower iron concentration (< 10 μg/ml) may produce the favorable effect on the metabolic activity of ECs. Conversely, the very high iron ion concentration (> 50 μg/ml) may have cytotoxicity on ECs. 相似文献