SILK SCAFFOLDS FOR BONE FORMATION

用于骨骼形成的丝质支架

• 批准号: 6634672
• 负责人: DAVID L. KAPLAN
• 金额: $ 19.53万
• 依托单位: TUFTS UNIVERSITY MEDFORD
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-01 至 2004-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6634672
• 关键词: DNA replication; alkaline phosphatase; biomaterial development /preparation; bone morphogenetic proteins; cell adhesion; collagen; femur; laboratory rat; macrophage; medical implant science; normal ossification; osteoblasts; osteocalcin; osteogenesis; parathyroid hormones; protein biosynthesis; protein engineering; stem cells; tissue /cell culture; tissue support frame; DNA replication; alkaline phosphatase; biomaterial development /preparation; bone morphogenetic proteins; cell adhesion; collagen; femur; laboratory rat; macrophage; medical implant science; normal ossification; osteoblasts; osteocalcin; osteogenesis; parathyroid hormones; protein biosynthesis; protein engineering; stem cells; tissue /cell culture; tissue support frame

DESCRIPTION: (verbatim) Temporary scaffolds for bone formation must meet a challenging set of requirements both in vitro and in vivo. These requirements will vary depending on whether the scaffold is to be used in vivo or for subsequent surgical transplantation, or for direct incorporation into the body as a biomaterial. In either case, the scaffolds must be biocompatible, mechanically robust, and tailorable to sustain sufficient integrity during repair or bone formation, assemble to fill in all parts of the repair site in vivo to avoid voids that can result in scar tissue, and eventually degrade to nontoxic materials. Silks exhibit excellent mechanical properties and can be genetically tailored to control sequence, composition and structure/properties. This control is particularly important for peptide coupling to these surfaces for control of types, densities and homogeneity of cell adhesion and bone formation. The ability to precisely control the placement and density of these factors is an essential feature in order to fully understand relationships between these peptides and bone growth in vivo or in vitro. Our hypothesis for the proposed study is that silk based polymers, because of their unique properties, including biocompatibility, high mechanical strength yet flexible with excellent resistance to compression, and our ability to genetically tailor the structures, can provide important 2D and 3 D scaffolds for bone formation. We plan to address this hypothesis by exploring the relationships between silk structure, growth factor types and decoration, and cell responses related to bone formation. Silk proteins will be prepared, including regenerated silkworm silk and different spider silks using recombinant DNA techniques (with and without encoded RGD and cysteines). The different silk substrates will be fabricated into 2D and 3D matrices and subsequently decorated by chemical coupling bone related growth factors (PTH 1-34, BMP-2)at different concentrations and in different combinations. Complete chemical, physical, and morphological analyses of these materials (e.g., CD, FTIR, ESEM, AFM, Contact Angle, XPS, TEM)will be conducted before and after cell studies. Cell responses to these matrices will be characterized in vitro using osteoblasts and stem cells and the studies will include assays for adhesion and spreading, DNA synthesis, collagen synthesis, alkaline phosphatase, osteocalcin, bone and mineralization. Macrophage assays in vitro and osteogenic potential and inflammation assessments in rat models in vivo will provide preliminary assessments of bone formation. A rat femur model will be used to study the best candidate silk biomaterials. The outcome of these studies will be the identification of the most promising silk-decorated matrices (appropriate types, densities and combinations of growth factors, and adhesion sites) for bone formation. All phases of the planed studies are supported with Preliminary Data that to demonstrate both the feasibility of the proposed experimental directions and the potential for this type of silk scaffolding to provide a new family of matrices for bone formation and eventually orofacial repair.

描述：（逐字）骨骼形成的临时支架必须满足 在体外和体内都具有挑战性的要求。这些要求 会根据要在体内还是用于 随后的手术移植或直接掺入体内 作为生物材料。无论哪种情况，脚手架都必须是生物相容性的， 机械稳健，可量身定制以维持足够的完整性 修复或骨形成，组装以填充维修地点的所有部分 体内避免可以导致疤痕组织的空隙，并最终降解为 无毒材料。丝绸具有出色的机械性能，可以是 基因量身定制的，以控制序列，组成和结构/特性。 这种控制对于肽耦合到这些表面尤为重要 用于控制细胞粘附和骨的类型，密度和均匀性 形成。精确控制这些的放置和密度的能力 因素是为了充分理解关系的重要特征 这些肽与体内或体外的骨骼生长之间。我们的假设 拟议的研究是基于丝绸的聚合物，因为它们的独特 特性，包括生物相容性，高机械强度却灵活 具有极好的压缩性，并且我们的遗传量身定制能力 这些结构可以为骨形成提供重要的2D和3 D支架。 我们计划通过探索丝绸之间的关系来解决这一假设 结构，生长因子类型和装饰以及与 骨形成。丝绸蛋白将准备好，包括再生蚕 丝绸和不同的蜘蛛丝使用重组DNA技术（使用和 没有编码的RGD和半胱氨酸）。不同的丝绸基材将是 制造成2D和3D矩阵，随后用化学装饰 在不同的 浓度和不同的组合。完整的化学，物理和 这些材料的形态分析（例如CD，FTIR，ESEM，AFM，接触 角度，XP，TEM）将在细胞研究之前和之后进行。细胞反应 这些矩阵将在体外使用成骨细胞和茎来表征 细胞和研究将包括粘附和扩散，DNA的测定 合成，胶原蛋白合成，碱性磷酸酶，骨钙素，骨骼和 矿化。巨噬细胞测定在体外和成骨潜力， 大鼠模型体内的炎症评估将提供初步 评估骨形成。大鼠股骨模型将用于研究最好的 候选丝绸生物材料。这些研究的结果将是 识别最有希望的丝绸装饰矩阵（合适的矩阵 生长因子的类型，密度和组合，以及粘附位点） 骨形成。策划研究的所有阶段都得到了初步的支持 可以证明提出的实验的可行性的数据 方向和这种类型的丝绸脚手架的潜力提供新的 用于骨形成的矩阵家族和最终的口面修复。