Department of Mechanical and Biomedical Engineering and National Centre for Biomedical Engineering Science, National University of Ireland, Galway, Ireland, UK.
Ann Biomed Eng. 2010 Jul;38(7):2263-73. doi: 10.1007/s10439-010-9972-y. Epub 2010 Mar 23.
Recent advances in angioplasty have involved the application of polymer coatings to stent surfaces for purposes of drug delivery. Given the high levels of deformation developed in the plastic hinge of a stent during deployment, the achievement of an intact bond between the coating and the stent presents a significant mechanical challenge. Problems with coating delamination have been reported in recent experimental studies. In this paper, a cohesive zone model of the stent-coating interface is implemented in order to investigate coating debonding during stent deployment. Simulations reveal that coatings debond from the stent surface in tensile regions of the plastic hinge during deployment. The critical parameters governing the initiation of delamination include the coating thickness and stiffness, the interface strength between the coating and stent surface, and the curvature of the plastic hinge. The coating is also computed to debond from the stent surface in compressive regions of the plastic hinge by a buckling mechanism. Computed patterns of coating delamination correlate very closely with experimental images. This study provides insight into the critical factors governing coating delamination during stent deployment and offers a predictive framework that can be used to improve the design of coated stents.
最近，血管成形术的进展涉及到在支架表面应用聚合物涂层，以达到药物输送的目的。考虑到支架在部署过程中在塑性铰处产生的高变形水平，实现涂层与支架之间的完整结合具有重大的机械挑战。最近的实验研究报告了涂层分层的问题。在本文中，实施了支架-涂层界面的内聚区模型，以研究支架部署过程中的涂层脱粘。模拟结果表明，在部署过程中，在塑性铰的拉伸区域，涂层从支架表面脱粘。控制分层起始的关键参数包括涂层厚度和刚度、涂层与支架表面之间的界面强度以及塑性铰的曲率。涂层还通过屈曲机制从塑性铰的压缩区域从支架表面脱粘。计算出的涂层分层模式与实验图像非常吻合。这项研究深入了解了支架部署过程中涂层分层的关键因素，并提供了一个预测框架，可用于改进涂层支架的设计。
