In vitro degradation of pure magnesium-the synergetic influences of glucose and albumin

The biocorrosion of magnesium in the external physiological environment is still difficult to accurately evaluate the degradation behavior in vivo,particularly,in the microenvironment of the patients with hyperglycemia or diabetes.Thus,we explored the synergistic effects of glucose and protein on the biodegradation of pure magnesium,so as to have a deeper understanding the mechanism of the degradation in vivo.The surface morphology and corrosion product composition of pure magnesium were investigated using SEM,EDS,FTIR,XRD and XPS.The effect of glucose and albumin on the degradation rate of pure magnesium was investigated via electrochemical and immersion tests.The adsorption of glucose and albumin on the sample surface was observed using fluorescence microscopy.The results showed that the presence of 2 g/L glucose changed the micromorphology of corrosion products on the magnesium surface by reacting with metal cations,thus inhibiting the corrosion of pure magnesium.Protein formed a barrier layer to protect the magnesium at early stage of immersion.The chelation reaction between protein and magnesium surface might accelerate the degradation at later stage.There may be a critical glucose(albumin)content.Biodegradation of pure magnesium was inhibited at low concentrations and promoted at high concentrations.The synergistic effect of glucose and protein restrained the adsorption of aggressive chloride ions to a certain extent,and thus inhibited the degradation of pure magnesium considerably.Moreover,XPS results indicated that glucose promoted the adsorption of protein on the sample surface.

Plain metallic biomaterials:opportunities and challenges

The‘plainification of materials’has been conceptualized to promote the sustainable development of materials.This perspective,for the first time in the field of biomaterials,proposes and defines‘plain metallic biomaterials(PMBs)’with demonstrated research and application case studies of pure titanium with high strength and toughness,and biodegradable,fine-grained and high-purity magnesium.Then,after discussing the features,benefits and opportunities of PMBs,the challenges are analyzed from both technical and regulatory aspects.Regulatory perspectives on PMB-based medical devices are also provided for the benefit of future research,development and commercialization.

纯镁的生物腐蚀研究

镁及其合金作为生物医用材料具有明显的优势,可以利用其耐蚀性差的特点,发展新型医用可降解镁金属材料.本文选择纯镁为主要研究对象,从杂质含量、加工处理状态等方面研究了两种纯镁在生理盐水中的腐蚀规律,表明降低纯镁中杂质元素的含量和细化晶粒可以提高纯镁在生理盐水中的开路腐蚀电位,减缓腐蚀速率.纯镁的腐蚀速率可以通过调整杂质含量、晶粒细化和固溶处理等方法进行控制,适宜发展成为一类新型的医用可降解金属材料.

白蛋白作用下纯镁的腐蚀行为

在模拟体液中添加牛血清白蛋白,建立生物生理环境,利用浸泡实验、电化学腐蚀实验测量纯镁的腐蚀降解行为。结果表明,白蛋白的加入抑制了纯镁在模拟体液中的腐蚀速率,并改变其阴、阳极反应过程,而且白蛋白浓度的增大会增强其抑制作用,但白蛋白的存在不会明显改变纯镁在模拟体液中的初期腐蚀类型,仍然以点蚀为主。

镁锌合金植入动物体内的分子生物相容性

背景:前期研究显示镁锌合金长期植入动物体内有较好的生物安全性。目的:观察将镁锌合金植入大鼠盲肠的分子生物相容性。方法:取72只SD大鼠,随机分成假手术组、纯钛组和镁锌合金组,每组24只。假手术组仅做盲肠切开缝合,纯钛组在盲肠切口周围包埋医用纯钛,镁锌合金组在盲肠切口周围包埋镁锌合金。手术前后检测血清谷丙转氨酶、肌酐、镁离子浓度及血小板衍化生长因子浓度,以及盲肠组织中转化生长因子β1表达情况。结果与结论:术后相同时间点3组间血清谷丙转氨酶、肌酐、镁离子浓及血清血小板衍化生长因子浓度,以及盲肠组织中转化生长因子β1表达差异无显著性意义(P>0.05)。镁锌合金组术后不同时间点血小板衍化生长因子浓度明显高于术前水平(P<0.05)。表明镁锌合金对大鼠肠道伤口愈合无明显影响,在肠道内有较好的分子生物相容性。

Mg/HA复合生物材料的制备及表面生物活性评价

用纯镁做基体,以化学沉淀法制备的类球状纳米羟基磷灰石(HA)粉体为增强体,采用粉末冶金法制备了含HA40%的HA/Mg复合材料。对所制备复合材料的组织、物相以及在模拟体液(simulated body fluid,简称SBF)中的生物活性进行了研究。结果表明:HA相均匀分布于镁基体中,形成理想的网状组织结构;复合材料在烧结后内部相组成以HA和Mg为主,烧结过程中没有发生化学反应;随着浸泡时间的延长,表面沉积物质增多,对其进行能谱分析发现沉积物质富含Ca、P和C元素,分析认为生成物为含碳酸根的羟基磷灰石,说明复合材料具有较好的生物活性。