Department of Mechanical Engineering, University of Colorado at Boulder, CO, USA; Section of Cardiovascular Medicine and Yale Cardiovascular Research Center, Yale University School of Medicine, New Haven, CT, USA; Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA.
Department of Mechanical Engineering, University of Colorado at Boulder, CO, USA.
Colloids Surf B Biointerfaces. 2019 Nov 1;183:110395. doi: 10.1016/j.colsurfb.2019.110395. Epub 2019 Jul 27.
Vascular implants remain clinically challenged due to often-occurring thrombosis and stenosis. Critical to addressing these complications is the design of implant material surfaces to inhibit the activities of platelets, smooth muscle cells (SMCs) and inflammatory cells. Recent mechanobiology studies accentuate the significance of material elasticity to cells and tissues. We thus developed and characterized an implant coating composed of hybrid, viscoelastic microfibers with coaxial core-sheath nanostructure. The coating over metallic stent material was formed by first depositing coaxially-electrospun fibers of poly(L-lactic acid) core and polyethylene glycol dimethacrylate sheath, and then polymerizing fibers with various UV times. Material characterizations were performed to evaluate the coating structure, mechanical property and biocompatibility. Results showed that coaxial microfibers exhibited arterial-like mechanics. The soft surface, high water content and swelling ratio of the coaxial fibers resemble hydrogels, while they are mechanically strong with an elastic modulus of 172-729 kPa. The coating strength and surface elasticity were tunable with the photopolymerization time. Further, the elastic fibers, as conformal coating on stent metal, strongly reduced SMC overgrowth and discouraged platelet adhesion and activation, compared to bare metals. Importantly, after 7-day subcutaneous implantation, coaxial fiber-coated implants showed more favorable in vivo responses with reduced tissue encapsulation, compared to bare stent metals or those coated with a two-layered fiber mixture composed of fibers from individual polymers. The excellent biocompatibility aroused from nanostructural interfaces of hybrid fibers offering hydrated, soft, nonfouling microenvironments. Such integrated fiber system may allow creation of advanced vascular implants that possess physico-mechanical properties of native arteries.
血管植入物由于经常发生的血栓形成和狭窄仍然具有临床挑战性。解决这些并发症的关键是设计植入材料表面，以抑制血小板、平滑肌细胞（SMCs）和炎症细胞的活性。最近的机械生物学研究强调了材料弹性对细胞和组织的重要性。因此，我们开发并表征了一种由具有共轴核-鞘纳米结构的混合粘弹性微纤维组成的植入物涂层。通过首先在金属支架材料上沉积具有聚（L-丙交酯）核和聚乙二醇二甲基丙烯酸酯鞘的同轴电纺纤维，然后用不同的 UV 时间聚合纤维，形成涂层。对材料特性进行了评估，以评估涂层结构、机械性能和生物相容性。结果表明，共轴微纤维表现出动脉样力学性能。共轴纤维的柔软表面、高含水量和高溶胀率类似于水凝胶，而它们具有机械强度，弹性模量为 172-729 kPa。涂层强度和表面弹性可以通过光聚合时间进行调节。此外，与裸金属相比，弹性纤维作为支架金属的 conformal 涂层，强烈抑制了 SMC 的过度生长，并抑制了血小板的黏附和激活。重要的是，与裸支架金属或由来自单个聚合物的纤维组成的双层纤维混合物涂覆的支架相比，共轴纤维涂层植入物在皮下植入 7 天后显示出更有利的体内反应，组织包裹减少。混合纤维的纳米结构界面提供了水合的、柔软的、不易结垢的微观环境，从而产生了优异的生物相容性。这种集成纤维系统可能允许创建具有天然动脉物理机械性能的先进血管植入物。
