Biodegradation mechanism and rate, biocompatibility, and toxicity for novel Zn-Mg stent materials

 产品说明：心脏病由于其对工业化国家的健康的巨大影响而引起巨大的社会兴趣，特别是在肥胖率高且典型饮食不利于心血管健康的发达国家。虽然侵入性手术不可取，但它们通常对确保患者生存至关重要。全世界每年使用的500万个冠状动脉支架在患者的一生中仍然存在于人体动脉中。这导致了一些严重的副作用的出现。随着时间的推移，无害地侵蚀掉的生物可吸收金属支架可以最大限度地减少与永久性支架相关的正常慢性风险。目前在设计这种可生物降解支架中所追求的Mg基和Fe基合金已经取得了有限的成功。密歇根理工大学提出的这项研究旨在首次开发一种锌基支架的替代产品线， vivo.初步研究表明，锌具有理想的生理腐蚀行为的生物可吸收支架应用。Zn-Mg支架的可行性、体内腐蚀行为和血管环境中的降解速率仍然是悬而未决的问题，并且是所提议项目的主题。将评价生物可吸收锌镁支架的总体可行性。将利用最近开发的动脉植入方法完成材料生物腐蚀的体内评价，其中将具有导丝几何形状的样品植入大鼠动脉壁。将制备锌镁合金，以定制材料性能，以接受 拉伸强度、断裂伸长率和渗透率的值。我们的初步研究表明，镁加入锌增加机械强度。此外，电/化学活性Mg添加将导致可调的生物腐蚀速率。该研究将导致选择和测试符合以下标准的锌镁合金：i）保持腐蚀速率接近0.02 mm/年值; ii）屈服强度>200 MPa，断裂伸长率>20%; iii）表现出与316 L不锈钢（支架材料的工业标准）相似的生物相容性。

 DESCRIPTION: Heart disease is of great societal interest due to its drastic impact on health in industrialized nations, especially in developed countries where obesity rates are high and the typical diet is not conducive to cardiovascular health. While invasive procedures are not desirable, they are often crucial to ensuring patient survival. The 5 million coronary stents administered world-wide each year remain present in the human artery for the lifetime of the patient. This has resulted in the emergence of several serious side effects. A bio absorbable metal stent that harmlessly erodes away over time could minimize the normal chronic risks associated with permanent stents. Mg- and Fe-based alloys currently pursued in designing such biodegradable stents have met with limited success. The research proposed at Michigan Tech aims to develop, for the first time, an alternative line of Zn-based stents that last 6-9 months in vivo. Preliminary study suggests that zinc exhibits ideal physiological corrosion behavior for bio absorbable stent application. The viability of a Zn-Mg stent, the corrosion behavior in vivo, and the degradation rate in the vascular environment remain open questions, and are the subjects of the proposed program. The overall feasibility of bio absorbable Zn-Mg stents will be evaluated. An in vivo evaluation of materials bio corrosion will be completed utilizing a recently developed arterial implantation method in which a sample with wire geometry is implanted into the arterial wall of a rat. Zn-Mg alloys will be prepared in order to tailor the material properties to accepted values of tensile strength, elongation to failure, and penetration rate. Our preliminary study has shown that the magnesium addition to zinc increases the mechanical strength. In addition, electro/chemically active Mg additions will lead to tunable rates of bio corrosion. The research will lead to selection and testing of a Zn-Mg alloy that meets the following criteria: i) keep corrosion rates close to the 0.02 mm/year value; ii) have >200 MPa yield strength, and >20% elongation to failure; and iii) exhibit biocompatibility similar to 316L stainless steel, industria standard for stent materials.