Recent advances in surface endothelialization of the magnesium alloy stent materials

Magnesium and its alloy have good mechanical properties and biodegradability,and have become the hotspot of the next-generation biodegradable vascular stent materials.However,their rapid degradation in vivo and poor biocompatibility are still the bottlenecks of clinical applications for the cardiovascular stents.In particular,how to induce the repair and regeneration of the vascular endothelial with normal physiological functions on the surface of the magnesium alloy stent materials represents the key to its clinical application in the field of cardiovascular stents.It has been believed that it is an ideal way to completely solve the postoperative complications through constructing the multifunctional anti-corrosive bioactive coating on the magnesium alloy surface to induce the formation of vascular endothelium with normal physiological functions.However,how to construct a corrosion-resistant multifunctional bioactive coating with the good endothelial regeneration abilities on the magnesium alloy surface still faces a great challenge.This paper mainly focused on highlighting and summarizing the recent advances in the surface endothelialization of the magnesium alloy materials for the vascular stent,including the bio-inert coating,in-situ immobilization of bioactive molecules on the surface,polymer coating loaded with bioactive factors,novel multifunctional polymer coating,bioactive micropatterns,bioactive layer with glycocalyx-like structure,NO-releasing coating and bioactive sol-gel coating.The advantages and disadvantages of these strategies were discussed and analyzed.Finally,in the senses of future development and clinical application,this paper analyzed and summarized the development direction and prospect of surface endothelialization of the magnesium alloy vascular stents.It is anticipated that this review can give the new cues to the surface endothelialization of the cardiovascular magnesium alloy stents and promote future advancements in this field.

Rational design, synthesis and prospect of biodegradable magnesium alloy vascular stents

Biodegradable magnesium(Mg) alloys are expected to be promising materials for cardiovascular stents(CVS), which can avoid the longterm clinical problems of current CVS, such as in-stent restenosis, late stent thrombosis, etc. Mg alloy stents exhibit superior biocompatibility and tunable biodegradability, compared with conventional permanent metallic stents. However, the poor formability and non-uniform corrosion of Mg alloy stents hinder their clinical application of CVS. This review focuses on the development of Mg alloys for CVS in recent years.According to the results of bibliometric analysis, we analyzed different biodegradable Mg alloy systems. Moreover, the structural design strategies for Mg alloy stents that can reduce the stress concentration, as well as the surface modification methods to control the corrosion behavior and biological performance of Mg alloy stents are also highlighted. At last, this review systematically discussed the potential directions and challenges of biodegradable magnesium stents(BMgS) in cardiovascular fields.

Understanding the corrosion of Mg alloys in in vitro urinary tract conditions: A step forward towards a biodegradable metallic ureteral stent

Ureteral stents play a fundamental role in modern time urology. However, following the deployment, stent-related symptoms are frequent and affect patient health and quality of life. Using biodegradable metals as ureteral stent materials have emerged as a promising strategy, mainly due to the improved radial force and slower degradation rate expected. Therefore, this study aimed to characterize different biodegradable metals in urinary tract environment to understand their propensity for future utilization as base materials for ureteral stents. The corrosion of 5 Mg alloys - AZ31, Mg-1Zn, Mg-1Y, pure Mg, and Mg-4Ag - under simulated urinary tract conditions was accessed. The corrosion layer of the different alloys presented common elements, such as Mg(OH)_(2), MgO, and phosphate-containing products, but slight variations in their chemical compositions were detected. The corrosion rate of the different metals varied, which was expected given the differences in the corrosion layers. On top of this, the findings of this study highlighted the significant differences in the samples' corrosion and corrosion layers when in stagnant and flowing conditions. With the results of this study, we concluded that Mg-1Zn and Mg-4Ag presented a higher propensity for localized corrosion, probably due to a less protective corrosion layer;Mg-4Ag corroded faster than all the other four alloys,and Mg-1Y stood out due to its distinct corrosion pattern, that showed to be more homogeneous than all the other four samples, making this one more attractive for the future studies on biodegradable metals.

A promoting nitric oxide-releasing coating containing copper ion on ZE21B alloy for potential vascular stent application

Magnesium-based biodegradable metals as cardiovascular stents have shown a lot of excellent performance, which have been used to treat coronary artery diseases. However, the excessive degradation rate, imperfect biocompatibility and delayed re-endothelialization still lead to a considerable challenge for its application. In this work, to overcome these shortcomings, a compound of catalyzing nitric oxide(NO) generation containing copper ions(Cu^(2+)) and hyaluronic acid(HA), an important component of the extracellular matrix, were covalently immobilized on a hydrofluoric acid(HF)-pretreated ZE21B alloy via amination layer for improving its corrosion resistance and endothelialization. Specifically,the Cu^(2+) chelated firmly with a cyclen 1,4,7,10-tetraazacyclododecane-N’, N’’, N’’’, N-tetraacetic acid(DOTA) could form a stability of hybrid coating, avoiding the explosion of Cu^(2+). The chelated Cu^(2+) enabled the catalytic generation of NO and promoted the adhesion and proliferation of endothelial cells(ECs) in vascular micro-environment. In this case, the synergistic effect of NO-generation and endothelial glycocalyx molecules of HA lead to efficient ECs promotion and smooth muscle cells(SMCs) inhibition. Meanwhile, the blood compatibility also had achieved a marked improvement. Moreover, the standard electrochemical measurements indicated that the functionalized ZE21B alloy had better anti-corrosion ability. In a conclusion, the dual-functional coating displays a great potential in the field of biodegradable magnesium-based implantable cardiovascular stents.

In vitro corrosion properties of HTHEed Mg-Zn-Y-Nd alloy microtubes for stent applications:Influence of second phase particles and crystal orientation

Magnesium(Mg)alloys are promising materials for cardiovascular stent applications due to their good biocompatibility and biodegradability.However,in vitro and in vivo corrosion tests reveal that Mg alloy stents suffer from a rapid corrosion rate and severe localized corrosion,which is limiting their widespread application.To solve the problem of uneven degradation of stents,a HTHE(long-time and high-temperature heat treatment,large-reduction-ratio hot extrusion)process is used to manufacture Mg-Zn-Y-Nd alloy microtubes in this study.The heat treatment is to dissolve alloying elements and reduce the size of SPPs,and the hot extrusion is to acquire fine-grained and strongly textured microtubes.The microstructural characterization shows that coarse second phases in as-cast alloy are refined and uniformly distributed in matrix of microtubes.After hot extrusion,microtubes show strong texture with basal plain oriented parallel to the longitudinal section(LS).The corrosion testing indicates that severe localized corrosion occurs on the cross section(CS)while localized corrosion is alleviated on the LS.Based on the different corrosion properties of the LS and CS,HTHEed microtubes are promising for solving the problems of rapid corrosion rate and severe localized corrosion of Mg alloy stents.

Degradation of Mg-Zn-Y-Nd alloy intestinal stent and its effect on the growth of intestinal endothelial tissue in rabbit model

Biodegradable magnesium alloys have excellent properties with respect to biodegradability, biocompatibility, and biomechanics, which may indicate a possibility of its application in intestinal stents. Investigation of Mg-Zn-Y-Nd alloy’s application in intestinal stents has been performed. This study aims to investigate the degradation behavior of Mg-Zn-Y-Nd alloy intestinal stents coated with poly(L-lactide)/paclitaxel in the intestinal environment and its biocompatibility with intestinal tissue. In this paper, Mg-Zn-Y-Nd alloy’s corrosion properties were evaluated by the immersion test in human feces, SEM and XRD, and animal tests. In vitro results showed that when the Mg-Zn-Y-Nd alloy was immersed in human feces for two weeks, its corrosion resistance could be improved by micro arc oxidation(MAO) and poly-l-lactide(PLLA) dual coating. Additionally, this result was also confirmed in vivo experiments by rabbit model. And animal tests also demonstrated that the Mg-Zn-Y-Nd alloy with MAO/PLLA/paclitaxel dual coating drug-eluting stents could inhibit the proliferation of local intestinal tissue around the stents. However, in vivo studies illustrated that the intestinal stents gradually degraded in rabbit model within 12 days.Considering the degradation rate of the stent was faster than expected in rabbits, the support performance of the scaffold requires further improvement.

A novel MgF2/PDA/S-HA coating on the bio-degradable ZE21B alloy for better multi-functions on cardiovascular application

Recently, functional molecules such as Polydopamine(PDA), Hyaluronic Acid(HA) and heparin have been widely studied in the field of surface modification of magnesium(Mg) alloy stents for better degradation behavior and biocompatibility, but their further application is limited by undesirable anticoagulant function, uncontrollable degradation and easy bleeding, respectively.Regarding to this consideration, a magnesium Fluoride/Polydopamine/Sulphonated hyaluronic acid(Mg F2/PDA/S-HA) composite coating was successfully prepared by applying S-HA with sulfur content of 9.71 wt% on the surface of ZE21B alloy in this study. The results showed that the composite coating with a unique mesh structure not only inherited the anticoagulant effect of sulfonic acid group and the excellent cyto-compatibility of S-HA with high sulfur content, but also significantly improved the corrosion performance of ZE21B alloy.These results indicate a great application potential of the composite coating in the field of cardiovascular biomaterials.

FEM for Design of Balloon Expandable Stent for Coronary Artery Using Co-Cr Alloy

Lately, cardiovascular diseases are becoming a critical issue to human health and patients suffer from such a disease tend to be increasing throughout the world due to the changes in lifestyle. As the remedies to cardiovascular diseases, a coronary artery bypass graft surgery （CABG） and a stent implantation have been widely used. In order to achieve successful results through these treatments, a stent must fulfill the certain conditions with its design and mechanical properties. A stent must have sufficient stiffness to secure the strength of narrowed blood vessel and sufficient fatigue strength against the pulsatory motion of the blood vessel. Also its high flexibility is mandatory not to damage the vessel wall while it is being transferred to the lesion through the blood vessel. A design of stent has considerable influence upon the performance of stent. Thickness, curvature and connection method of strut are main variable factors in stent design.

记忆合金椎体支架在猪椎骨内的植入实验

目的探讨记忆合金椎体支架在动物椎体内扩张支撑的初步结果,检验支架设计的可操作性。方法将自行研制的记忆合金可扩张椎体支架植入猪椎体,可吸收骨材料填充入椎体支架空腔内。实验对同一猪选择两节椎体L1、L3间隔植入的对照方式。本次实验选用3头大白猪:1号猪(编号8420)、2号猪(编号8439)、3号猪(编号8424),分7、13、26周3个时间观察点作为终末结果观察节点。术后4周与实验预定结束时间点前1周采集X线片,实验结束后取标本的Micro-CT影像观测支架在猪椎体内的植入情况,对支架在椎体内的稳定性和支架扩张结果进行分析。结果支架在植入椎体内的操作过程中顺利,获得微创置入预期;支架植入椎体内如期扩张并且随即稳定卡在椎体空腔内。在本实验的观察过程中,2号猪(编号8439)术后出现犬坐,术后3 d恢复正常行走,但在第46 d发现死亡,检查后为睾丸疝,因与实验时间差距不大,其实验结果被列入观察,将2号猪(编号8439)与1号猪(编号8420)互换观察,1号猪(编号8420)与3号猪(编号8424)完成后两组实验观察。支架植入猪椎体在影像观察中未见滑移、移出椎体。大体标本观察,支架均稳定在椎体内。支架在植入后4周与处死前1周的影像测量中高度略有变化,术后4周支架影像测量高度为(8.967±0.952)mm,处死前1周的支架影像测量高度为(9.532±0.708)mm,两者比较差异有统计学意义(P<0.05)。结论记忆合金椎体支架具有良好的临床可操作性与椎体内植入的安全性,具有良好的力学支撑和椎体内的可扩张性能;记忆合金可扩张椎体支架对于椎体压缩骨折的微创治疗是一项有前景的微创技术。

Multi-objective structural optimization and degradation model of magnesium alloy ureteral stent

Background:Mg alloys have attractive properties,including biocompatibility,biodegradability,and ideal mechanical properties.Moreover,Mg alloys are regarded as one of the promising candidates for manufacturing ureteral stents.This study proposed a multi-objective optimization method based on the Kriging surrogate model,NSGA-III,and finite element analysis to improve the degradation performance of Mg alloy ureteral stents.Methods:The finite element model for the degradation of Mg alloy ureteral stents has been established to compare the degradation performance of the stents under different parameters.Latin hypercube sampling was adopted to generate train sample points in the design space.Meanwhile,the Kriging surrogate model was constructed between strut parameters and stent degradation behavior.The NSGA-III was utilized to determine the optimal solution in the global design space.Results:The optimized stent achieved 5.52degradation uniformity(M),10degradation time(DT),and 4work time(FT).The errors between the Kriging surrogate model and the finite element calculation results were less than 6%.Conclusion:The optimized stent achieved better degradation performance.The degradation behavior of stents was dependent on the design parameters.The multi-objective optimization method based on the Kriging surrogate model and finite element analysis was effective in stent design optimization problems.

新型混编支架的制备与径向支撑力学行为

背景:编织支架因良好的柔顺性被广泛应用于狭窄动脉的治疗,但在提供足够的径向支撑性能方面存在明显局限。目的:针对单一材料制成的编织支架存在径向支撑力不足的问题,采用不同力学参数的生物可降解材料混合编织支架,探究影响混编支架径向力学性能的影响因素。方法:在镁合金支架中引入铁合金纱线,采用有限元分析法对不同编织参数的混编支架进行参数化分析,通过与0.18 mm直径镁合金纱线制备的普通支架进行对比,评估其径向支撑力、径向回弹率和扩张不均匀性。结果与结论:①当铁合金纱线直径为0.18 mm和0.14 mm时,随着铁合金纱线数量的增多,混编支架的径向支撑力增加;此时,尽管直径0.14 mm铁合金纱线提供的径向支撑力小于同数量的0.18 mm铁合金纱线,但增加细铁合金纱线的数量可以达到与较粗铁合金纱线混编支架相媲美的径向支撑力。当铁合金纱丝直径为0.10 mm时,随着铁合金纱线数量的增加,混编支架的径向支撑力降低。②增大编织角度,混编支架的径向支撑力降低,但其径向回弹率和狗骨率得到了改善。通过降低编织角可以改善小直径铁合金纱线造成的支架径向支撑力不足。③结果显示,在镁合金支架中引入铁合金纱线,可以实现在不增加纱线直径的情况下精确地调整支架的径向力学性能,这不仅克服了单一材料支架的局限性,也为多材料支架的设计提供了新思路。

纯钛支架钴铬合金支架义齿修复治疗伴有轻中度牙周病牙列缺损患者的疗效

目的探讨纯钛支架、钴铬合金支架义齿修复治疗轻中度牙周病伴牙列缺损的疗效及对龈沟液C反应蛋白(CRP)、肿瘤坏死因子α(TNF-α)及白细胞介素-6(IL-6)水平的影响。方法选择2021年1月至2022年12月本院轻中度牙周病伴牙列缺损患者120例,按照患者佩戴不同金属种类的义齿将其分为钴铬合金组和纯钛组,钴铬合金组40例采用钴铬合金支架可摘义齿修复治疗,纯钛组40例采用纯钛支架可摘义齿修复治疗,随访1年。观察2组临床疗效、咀嚼效率及随访期间不良症状发生情况。另外,以采用不含金属的树脂材料活动义齿修复治疗40例为空白对照组,对比3组龈沟液炎症水平。结果纯钛组和钴铬合金组总治疗有效率差异无统计学意义(P>0.05);2组修复6个月后的咀嚼效率均高于修复前,且纯钛组高于钴铬合金组(P<0.05)。3组修复1个月后的龈沟液CRP、TNF-α及IL-6水平均低于修复前,且钴铬合金组>纯钛组>对照组,两两对比差异有统计学意义(P<0.05);纯钛组随访1年内的不良症状发生率明显较钴铬合金组低(P<0.05)。结论纯钛支架、钴铬合金支架可摘义齿修复均为临床治疗轻中度牙周病伴牙列缺损的有效手段,虽然两种金属支架均不可避免会导致一定的龈沟液炎症,但纯钛支架更有利于提高咀嚼效果,缓解龈沟液炎症,并预防各种不良症状的发生。

Preparation of functional coating on magnesium alloy with hydrophilic polymers and bioactive peptides for improved corrosion resistance and biocompatibility

Biodegradable magnesium alloy stents(MAS)have great potential in the treatment of cardiovascular diseases.However,too fast degradation and the poor biocompatibility are still two key problems for the clinical utility of MAS.In the present work,a functional coating composed of hydrophilic polymers and bioactive peptides was constructed on magnesium alloy to improve its corrosion resistance and biocompatibility in vitro and in vivo.Mg-Zn-Y-Nd(ZE21B)alloy modified with the functional coating exhibited moderate surface hydrophilicity and enhanced corrosion resistance.The favourable hemocompatibility of ZE21B alloy with the functional coating was confirmed by the in vitro blood experiments.Moreover,the modified ZE21B alloy could selectively promote the adhesion,proliferation,and migration of endothelial cells(ECs),but suppress these behaviors of smooth muscle cells(SMCs).Furthermore,the modified ZE21B alloy wires could alleviate intimal hyperplasia,enhance corrosion resistance and re-endothelialization in vivo transplantation experiment.These results collectively demonstrated that the functional coating improved the corrosion resistance and biocompatibility of ZE21B alloy.This functional coating provides new insight into the design and development of novel biodegradable stents for biomedical engineering.

西罗莫司-聚三亚甲基碳酸酯改性镁合金的降解和药物释放行为

背景:冠状动脉镁合金支架腐蚀速率及药物释放的双重调控是目前镁合金支架需要解决的重要课题。可降解载药聚合物涂层作为一种有前途的改性策略引发了广泛关注。目的:研究可降解载药聚合物涂层修饰对镁合金降解的影响,以及镁合金降解对可降解载药聚合物涂层药物释放的影响。方法:制备不同的药物聚合物溶液,溶液S1:西罗莫司0.01 g、聚三亚甲基碳酸酯0.005 g、二氯甲烷1 mL;溶液S2:西罗莫司0.01 g、聚三亚甲基碳酸酯0.01 g、二氯甲烷1 mL;S3:西罗莫司0.01 g、聚三亚甲基碳酸酯0.02 g、二氯甲烷1 mL;S2-1:西罗莫司0.01 g、聚三亚甲基碳酸酯0.01 g、0.001 g聚乙二醇400、二氯甲烷1 mL;S2-2:西罗莫司0.01 g、聚三亚甲基碳酸酯0.01 g、0.002 g聚乙二醇400、二氯甲烷1 mL。将5种药物聚合物溶液涂覆在AZ31镁合金表面制备涂层,对比涂层在镁合金基底上的药物释放行为差异,以及各涂层对镁合金腐蚀能力的影响;探索基底对西罗莫司-聚三亚甲基碳酸酯涂层的影响;考察各修饰镁合金的体外细胞相容性与血液相容性。结果与结论:①西罗莫司-聚三亚甲基碳酸酯涂层的修饰可以大幅增强镁合金的耐腐蚀能力,随着载药涂层的药物释放,涂层中形成微观水通道,涂层的腐蚀防护能力逐渐下降;浸泡后期金属降解产生的碱性微环境对药物释放起到一定的加速作用;涂层中药物占比的升高或聚乙二醇的加入会加快药物释放速率,但也加快了金属腐蚀速率;以上结果说明镁合金降解和药物涂层降解之间具有一定的双向促进效应,即镁合金的降解促进药物涂层的降解,而药物涂层的降解造成的孔隙也反过来进一步加快镁合金的降解。②5种药物涂层可有效抑制人血管内皮细胞与人血管平滑肌细胞的增殖与贴附,既不会引发溶血反应,也不影响内外源凝血机制(不同涂层参数的影响效果有小幅度的差异)。

镁合金外支架辅助自体牙异位移植

目的:探索微弧氧化处理的镁合金支架辅助自体牙异位移植的可行性。方法:拔除9只雌性比格犬(9~11 kg)的左下颌第二前磨牙、左下颌第三前磨牙和右下颌第二前磨牙,截冠得犬牙根,3Shape扫描形态制作微弧氧化镁合金支架并装配自体牙根,3个月后植入牙槽窝,同时植入1个钛合金种植体和自体牙根进行对照;植入后3、6、12个月分三批处死实验犬,每批3只。截取骨组织标本进行Micro-CT扫描、切片VG染色观察。结果:Micro-CT结果显示,镁合金支架组成骨效果在各时间点均优于钛合金组和自体牙组。VG染色结果可见,无论是在哪个时间点,镁合金支架组的骨接触率均高于钛合金种植体组,自体牙组最低,且差异具有统计学意义(P<0.05)。结论:与自体牙移植和钛合金种植体相比,镁合金支架辅助的自体牙异位移植可以有效促进机体形成新骨,有利于提高移植牙的初期稳定性。

纳米晶NiTi形状记忆合金在生物医用中的应用展望

传统的NiTi合金具有超弹性、形状记忆效应及优异的生物相容性在众多领域都有广泛应用,例如:在生物医用领域被制备成口腔正畸弓丝和血管支架。但生物医用器材需要精密化及小型化,传统NiTi合金已经跟不上发展,经过严重塑性变形的纳米晶NiTi合金比传统的粗晶和超细晶NiTi合金拥有更好的拉伸、抗压强度、塑性和疲劳性能等性能。有望扩大在生物医用领域的应用范围。纳米晶NiTi合金可以用于新型医疗器械制造和骨科生物材料,与Ag组合成NiTiAg三元合金不仅力学性能优异,还附带抗菌效果;与W纳米线/带复合形成W-NiTi复合材料提高辐射不透明度,使器械和植入物在人体内的定位和部署更加简单。近年来,还有一种新型表面改性技术:超声波纳米晶表面改性,在NiTi合金表面产生纳米结晶以改善疲劳和耐腐蚀性能等。主要介绍现有的NiTi合金的应用以及纳米晶NiTi合金在生物医用领域的应用展望。

医用金属材料促血管生成的分子机制

背景:血管生成对于组织修复与再生是必不可少的,提高医用金属材料促血管生成的能力是近年来的研究热点。目的:整理讨论了医用金属材料促内皮细胞血管化的可能分子机制,为后续研发各种促血管生成的医用金属材料奠定基础。方法:检索PubMed、ScienceDirect、中国知网和万方数据库收录的相关文献。英文检索词为“medical metal materials OR alloy”“stent OR scaffold”“vascularization OR angiogenesis”“molecular mechanism OR signaling pathway”“endothelial cells”,中文检索词为“医用金属材料、金属”“支架”“血管化、血管生成”“分子机制、信号通路”“内皮细胞”,最终纳入76篇文献进行分析总结。结果与结论:①医用金属材料植入机体后在降解过程中所释放的金属离子,可以通过促进内皮细胞的增殖、迁移、黏附和提高成管能力来影响血管生成。②镁、锌、铜、锶及钴等金属离子可以激活Wnt、PI3K/Akt、MAPK、缺氧诱导因子1α/血管内皮生长因子等信号通路,上调血管内皮生长因子、血小板衍生生长因子及缺氧诱导因子1α等血管生成因子的表达,促进血管生成相关细胞因子的分泌,从而诱导血管生成。③金属植入体内引起的免疫反应不仅影响植入材料的稳定性,还会影响血管化及成骨效果。④金属离子的浓度会影响血管生成的过程,金属材料降解过快,金属离子爆发积累会导致细胞毒性。确定金属离子最佳促血管化及成骨分化的浓度,是开发多功能金属材料的关键。⑤通过合金化、表面修饰改性等手段提高金属材料的耐腐蚀性,调控金属离子释放速率,有利于营造良好的成骨和血管生成微环境,加速组织的修复与再生。⑥金属促血管生成的机制丰富,但具体分子机制尚未彻底明晰,未来仍需进一步的研究。

钛合金支架—明胶复合载药体系的制备及其抗菌性研究

目的:探究提高钛合金骨植入材料的抗菌性及生物相容性的有效方法。方法:本文以3D打印的多孔钛合金为支架,将负载有庆大霉素的明胶填充于其中以制备复合骨植入材料;通过红外吸收光谱、水溶性及体外药物释放测试评价不同载药量对明胶稳定性的影响;利用细菌黏附、细菌活性以及抑菌圈实验分析该复合材料的抗菌性能;采用细胞活性实验评价该材料的生物相容性。结果:不同载药量下明胶的耐水性均达到6 d,药物释放效应可维持到明胶完全溶解;载药量的提升能更有效地抑制大肠杆菌(E. coli)和金黄色葡萄球菌(S. aureus)的生长,在载药量为8 mg/mL的情况下,两种细菌的抑菌圈最大;细胞毒性分析发现不同载药量对成骨细胞的活性无显著影响(P>0.05)。结论:此复合骨植入体材料具有良好的体外抑菌性能及生物相容性。

镁合金生物材料降解对内皮化细胞的影响

背景:镁合金材料依靠其优良的生物相容性和可降解性被誉为“革命性的金属材料”,其降解对内皮化的影响具有重大研究意义。目的:综述镁合金材料的研究进展。方法:利用计算机检索PubMed、中国知网数据库、Web of Science和Elsevier等数据库中的相关文献,以“金属生物材料,镁合金材料,血管支架,内皮化,动物实验,体外实验”为中文主题检索词,以“Metallic biomaterials,Magnesium alloys,Vascular stents,Endothelialization,Animal experiments,In vitro”为英文检索词进行检索,检索时限为2015-2022年,通过阅读文题和摘要进行初步筛选,最终纳入116篇文献进行结果分析。结果与结论:镁合金材料降解形成的含一定浓度镁离子的微环境有利于内皮细胞及平滑肌细胞的增殖,镁离子对内皮化的作用基本被认可。但降解速率过快是镁合金的最大问题,镁离子浓度过高会出现细胞毒性,因此目前的研究多集中于改善其降解,提高生物相容性。目前常见的改善镁合金降解的方法有纯化、合金化、表面改性,均可提高其耐腐蚀性,并且不同元素的合金化对镁合金的改善是不同方面,未来可能针对不同需求来选择不同合金化的镁合金以适应临床患者的情况,除引入其他元素外,改进镁合金的制作工艺改善降解问题也可能是一种值得尝试的方法。

钛镍合金丝材电解抛光工艺的研究

添加柠檬酸和甘油对高氯酸-甲醇基础抛光液进行优化,用不同抛光液对钛镍合金丝材进行电解抛光,对比研究了抛光前后丝材的表面形貌、抗腐蚀性和血液相容性。结果表明,添加柠檬酸和甘油后抛光液缓蚀效果明显,增加了抛光过程的可控性;与抛光前相比,优化后抛光液电解抛光的钛镍丝材表面平整,平均粗糙度从161.3 nm降至15.6 nm,自腐蚀电位从-0.167 V升至0.045 V,磷酸盐缓冲液中镍溶出量更低,抗腐蚀性提高,溶血率从2.333%降至0.333%,血小板黏附数量明显减少,血液相容性得到改善。