Surfactant-Templated Polyurea-Nanoencapsulated Macroporous Silica Aerogel, a Potential New Biomaterial for Artificial Heart Valves

ID：MPS/DMR/BMAT（7623）0907291 主要研究者：尹伟 ORG：俄克拉荷马州表面活性剂模板化聚脲纳米胶囊化大孔二氧化硅气凝胶：一种潜在的人工心脏瓣膜新生物材料该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。智力优势：二氧化硅气凝胶是介孔材料，形成为湿硅胶，并通过超临界流体萃取孔隙填充凝胶化溶剂进行干燥。它们重量轻，孔隙率高，但通常机械强度低。最近，Co-PI Leventis开发了一种在保形聚合物涂层下纳米封装3D二氧化硅纳米结构而不堵塞孔隙的方法。这种新型轻质材料，称为交联气凝胶（X-气凝胶），具有显着提高的机械强度，并具有类似于生物相容性聚氨酯的表面化学。这里提出将这种材料开发为用于人工心脏瓣膜的小叶材料，现在通常由热解碳制成。 假设X-气凝胶瓣叶的重量较轻将导致跨瓣压较低并减少血液中的气穴现象。 这一假设将通过以下具体目的进行检验：（1）确定X-气凝胶对血浆、血细胞（特别是血小板）和血管内皮细胞的生物相容性。 (2)表征X-气凝胶在压缩、拉伸、剪切和双轴应力状态下的机械行为和化学稳定性;还将测试材料的蠕变、松弛、断裂和疲劳。(3)制备X-气凝胶单叶心脏瓣膜，并确定其在具有匹配体内循环的动态特性的流动室中的血液动力学性能。 更广泛的影响：鉴于需要外科瓣膜置换术的心脏瓣膜缺陷的患病率以及人工心脏瓣膜的预计持续需求，该材料开发提案具有显著临床影响的潜力。 该项目由一个非常跨学科的团队领导，它为跨化学，材料科学和生物医学工程的学生提供了极好的培训机会。 研究生和本科生都将接受该项目的培训。 已经为俄克拉荷马州和密苏里州罗拉站点之间的PI和学生访问做出了规定。

ID: MPS/DMR/BMAT(7623) 0907291 PI: Yin, Wei ORG: Oklahoma StateTitle: Surfactant-Templated Polyurea-Nanoencapsulated Macroporous Silica Aerogel: A Potential New Biomaterial for Artificial Heart ValvesThis award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).INTELLECTUAL MERIT: Silica aerogels are mesoporous materials formed as wet silica gels and dried by supercritical fluid extraction of the pore-filling gelation solvent. They are lightweight with high porosity but typically have low mechanical strength. Recently, Co-PI Leventis developed a method to nanoencapsulate 3D silica nanostructures under a conformal polymer coating without clogging the pores. This novel lightweight material, termed crosslinked aerogel (X-aerogel), has a significantly improved mechanical strength and possesses surface chemistry resembling biocompatible polyurethane. It is proposed here to develop this material as a leaflet material for artificial heart valves, typically made now of pyrolytic carbon. It is hypothesized that the lighter weight of X-aerogel valve leaflets will lead to lower transvalvular pressures and reduced cavitation in the blood. This hypothesis will be tested through the following specific aims: (1) To determine the biocompatibility of X-aerogels towards plasma, blood cells (especially platelets) and vascular endothelial cells. (2) To characterize the mechanical behavior and chemical stability of X-aerogels under compressive, tensile, shear, and bi-axial stress states; creep, relaxation, fracture, and fatigue of the material will also be tested. (3) To manufacture an X-aerogel monoleaflet heart valve and determine its hemodynamic performances in a flow chamber with dynamic properties matching the in vivo circulation. BROADER IMPACTS: In view of the prevalence of heart valve defects requiring surgical valve replacement and the projected continuing need for artificial heart valves, this materials development proposal has the potential for significant clinical impact. The project is headed by a very interdisciplinary team, and it provides excellent opportunities for training of students across the boundaries of chemistry, materials science, and biomedical engineering. Both graduate students and undergraduate students will be trained on the project. Provisions have been made for visits by PIs and students between the Oklahoma State and Missouri Rolla sites.