Materials World Network: Nano-Macro Porous Glass Bone-Scaffolds

细胞生物学和材料科学的进步导致了通过在生物相容的支架上向损伤部位提供健康的祖细胞来修复或再生丢失或受损组织的概念。这种最理想的治疗方法的成功取决于3D结构的发展，细胞可以附着在3D结构上并形成牢固的结合。理想的支架材料应该与宿主组织的生物力学相似，并且必须是生物相容的，最好是生物活性的，以便主动控制组织的生长。这种方法在使用CaO-P2O5-SiO_2基玻璃制成的骨支架进行骨替代方面取得了最成功的结果。一个宏大的多孔结构是通过快速血管化和骨生长获得良好的种植体结合所必需的，但理想的支架应该包括模拟结缔组织发育的细胞外环境的纳米孔。因此，理想的骨支架必须由纳米大孔的双峰分布组成。不存在用于在具有规定的机械和生物兼容性特性的生物活性玻璃中制造双峰孔隙率的方法。因此，我们提出了一套完整的研究方案，用于构建骨支架，并在可控的体外和现实的体内环境(利用骨髓间充质干细胞进行牙槽骨再生)下验证其有效性。Sol-Gel方法将是玻璃制备的主要方法，它将通过聚合诱导相分离与Sol-Gel转变同时进行，或通过大孔模板在现有的生物玻璃类型组成中引入双峰孔洞。为了优化玻璃的成分和工艺参数，我们将研究玻璃的体积和表面、骨-支架界面和新形成的骨的物理和化学结构。我们的目标范围非常广泛，将由玻璃合成化学家、物理玻璃科学家、表面科学家、具有组织工程专业知识的牙医和生物力学专家共同努力，组成一个由来自埃及、葡萄牙、塞内加尔和美国的五个小组组成的团队。就广泛的影响而言，该项目将有助于开发一种更好的治疗老龄化人口或创伤患者骨组织丢失的方法。我们的新型生物活性纳米多孔玻璃支架不仅可以帮助骨科患者，还可能为药物输送和细胞包裹引入新的技术。它将展示材料科学和工程学在推进医学尖端方面的好处。它还将帮助建立一个由跨学科材料研究人员组成的有重点的材料世界网络，并为来自三大洲的四个国家培养年轻科学家，实现一个共同的目标。该项目将在两个发展中国家创建第一个生物活性材料综合研究计划，从而为这一研究领域的未来研究树立一个典范。该项目的影响将通过与国家稳定机构、利哈伊大学和普林斯顿大学的两个国际材料研究所结盟而扩大。该奖项由美国国家科学基金会国际科学与工程办公室的非洲和近东项目共同资助。

Advances in cell biology and material science have led to the concept of repairing or regenerating lost or damaged tissue by providing healthy progenitor cells to the injured site on a biocompatible scaffold. The success of this most desirable treatment rests on the development of 3D structures to which cells can attach and form firm bonds. The ideal material to make such scaffolds should be biomechanically similar to the host tissue and must be biocompatible, preferably be bioactive so as to actively control tissue growth. The most successful results of this approach have been obtained for bone replacement using bone-scaffolds made from CaO-P2O5-SiO2 based glasses. A macro porous structure is necessary to obtain good implant incorporation through rapid vascularization and bone ingrowth, yet an ideal scaffold should consist of nanopores that simulate the extracellular environment for the development of connective tissue. Thus an ideal bone-scaffold must consist of a bimodal distribution of nano-macro pores. The process for fabricating bimodal porosity in a bioactive glass with prescribed mechanical and biocompatibility properties does not exist. Therefore, a comprehensive research program is proposed for fabricating bone-scaffolds and demonstrating their efficacy under controlled in vitro and realistic in vivo environment (alveolar bone regeneration utilizing bone marrow mesenchymal stem cells). Sol-gel method will be the primary method of glass preparation in which bimodal porosity will be introduced in established Bioglass type compositions either by polymerization-induced phase separation simultaneously with the sol-gel transition, or via macroporous templates. To optimize the glass composition and processing parameters, we will investigate the physical and chemical structure of the bulk and surface of glass, the bone-scaffold interface, and newly formed bone. The very broad scope of our goal will be pursued collaboratively by glass synthesis chemists, physical glass scientists, surface scientists, dentists with expertise in tissue engineering, and biomechanics specialists, forming a team of five groups from Egypt, Portugal, Senegal and USA.With regard to broad impact, the project will help develop a better treatment of bone tissue loss in aging population or patients suffering from a trauma. Our novel bioactive nano-macro porous glass-scaffold would not only help orthopedic patients, but may also introduce new technology for drug delivery and cell encapsulation. It will demonstrate the benefits of materials science and engineering in advancing the cutting edge of medicine. It will also help establish a focused materials world network of researchers in cross-disciplinary materials research, and train young scientists in four countries from three continents with one common goal. The project will be creating the first comprehensive research programs of bioactive materials in two developing countries, and thus setting a model for future research in this area of research. The projects impact will be amplified via its alignment with NSFs two International Materials Institutes at Lehigh and Princeton Universities. This award is co-funded by the Africa and Near East Programs of the NSF Office of International Science and Engineering.