Improved Biocompatibility and Biodegradation of Zn-based Stent Materials through Surface Nano-Engineering

通过表面纳米工程改善锌基支架材料的生物相容性和生物降解性

• 批准号: 8871928
• 负责人: Jaroslaw W Drelich
• 金额: $ 20.4万
• 依托单位: MICHIGAN TECHNOLOGICAL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-04-01 至 2017-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8871928
• 关键词: Alloys; American Heart Association; Arteries; Behavior; Biocompatible; Biodegradation; Blood Vessels; Characteristics; Chronic; Corrosion; Engineering; Environment; Evaluation; Exhibits; Failure; Film; Geometry; Implant; Lead; Lithium; Magic; Metals; Methods; Michigan; Modification; Oxides; Penetration; Physiological; Property; Rare Earth Metals; Rattus; Research; Risk; Sampling; Solutions; Stents; Structure; Surface; Tensile Strength; Testing; Thick; Time; Zinc; base; biomaterial compatibility; design; implant material; implantation; improved; in vivo; meetings; nanoengineering; percutaneous coronary intervention; programs; public health relevance; statistics; success

 DESCRIPTION: Metal stents are commonly used to revascularize occluded arteries. The American Heart Association states that 622,000 percutaneous coronary interventions were performed in 2007 (the most recent period for which statistics have been compiled). 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 are currently pursued in designing such biodegradable stents with a limited success. Only one commercial Mg-based stent called Lekton Magic Stent and developed by Biotronik was recently introduced but it dissolves away too fast and involves rare earth elements, which have unknown biocompatibility. 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 and contain biocompatible Li. Preliminary study suggests that zinc exhibits ideal physiological corrosion behavior for bio absorbable stent application. The viability of a zinc stent was demonstrated in our preliminary study. The corrosion behavior in vivo for zinc and zinc-lithium with a passive layer of oxide film and its effect on the degradation rate in the vascular environment remain open questions, and are the subjects of the proposed program. The overall feasibility of a bio absorbable zinc and zinc-based stents with engineered surfaces 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. Zinc-lithium alloys will be prepared in order to tailor the material properties to accepted values of tensile strength, elongation to failure, and penetration rate. Oxide films of varying thickness and structure will be formulated on surfaces of both zinc and zinc-lithium alloys using an anodization. The surface engineering of thin oxide films will lead to tunable rates of bio corrosion. The research will lead to selection of surface modification characteristics that meets the following criteria: i) improve hemocompatibility and biocompatibility and zinc-based implant materials; ii) keep corrosion rates below the 0.02 mm/year value in the first 3-4 months; and iii) will not protect metal from accelerated (>0.02 mm/year) biodegradation after 4 months.

 描述：金属支架通常用于闭塞动脉的血运重建。美国心脏协会指出，2007年（最近的统计数据已汇编）进行了622，000例经皮冠状动脉介入治疗。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。目前在设计这种生物可降解支架时采用Mg基和Fe基合金，但成功有限。最近只有一种名为Lekton Magic Stent的商业镁基支架由Biotronik开发，但它溶解得太快，并且含有稀土元素，这些元素具有未知的生物相容性。密歇根理工大学提出的这项研究旨在首次开发一种替代性的锌基支架，该支架在体内可持续6-9个月，并含有生物相容性的锂。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。我们的初步研究证明了锌支架的可行性。锌和锌锂在体内的腐蚀行为与钝化层的氧化膜及其对血管环境中的降解速率的影响仍然是开放的问题，是拟议计划的主题。将评价具有工程表面的生物可吸收锌和锌基支架的总体可行性。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。锌锂合金将成为 为了将材料性能调整到可接受的拉伸强度、断裂伸长率和渗透率的值而制备。不同厚度和结构的氧化膜将被 使用阳极氧化在锌和锌-锂合金的表面上配制。薄氧化膜的表面工程将导致可调的生物腐蚀速率。这项研究将导致 选择符合以下标准的表面改性特性：i）改善血液相容性和生物相容性以及锌基植入材料; ii）在前3-4个月内将腐蚀速率保持在0.02 mm/年以下;以及iii）在4个月后不会保护金属免受加速（>0.02 mm/年）生物降解。