Click Chemistry for Immobilized Bone Morphogenetic Protein

描述（由申请人提供）：项目摘要/摘要：美国每年有超过630万例骨折，其中约70万例难以愈合。对于不愈合或愈合缓慢的骨折，可用的治疗选择是有限的。骨形态发生蛋白是刺激新骨产生的生长因子，并已获得FDA批准用于骨折修复和脊柱融合。对于BMP的大多数临床批准的用途，可吸收的胶原海绵被用作递送基质以将BMP保留在修复部位。BMP对胶原蛋白的低亲和力导致BMP的快速扩散，因此，需要超生理水平的BMP来促进愈合。Affinergy开发肽类大分子，界面生物材料（IFBM），调节生物表面之间的关键界面，以启动和指定界面生物活性。所研究的IFBM由对BMP和胶原海绵具有亲和力的不同肽模块组成。该技术的局限性是构建许多不同IFBM以促进快速筛选用于随后的体内评价的能力。[3+2]环加成或“点击化学”将用于制备IFBM，因为这利用了我们的模块化方法，并且通过较短肽（<25聚体）的偶联允许更高的总产率。作为一个模型系统，我们将识别，合成和表征IFBM，结合再生胶原海绵和生长因子，持续释放骨形态发生蛋白（BMP），以改善骨折部位的骨愈合。具体目标是：目标1：使用点击化学优化用于偶联不同分子量和序列的肽的反应条件。目的2：从利用相展示鉴定的肽中筛选合成的IFBM文库，并测定其与BMP-2的体外结合亲和力。目标3：评价具有不同BMP亲和力的BMP-IFBM涂覆的胶原海绵在C3 H10 T1/2小鼠间充质细胞系中诱导成骨细胞分化的体外能力。本SBIR的目的是证明IFBM可与可吸收材料一起使用，以控制生长因子向骨损伤的输送，从而改善愈合和临床结局。美国每年有超过630万例骨折，其中约70万例难以治愈。骨形态发生蛋白（BMP）是刺激新骨生成的生长因子，已获得FDA批准。目前，可再吸收的胶原海绵被用作BMP的递送基质。BMP对海绵的低亲和力导致差的递送特征，需要超生理水平的BMP来促进愈合。在这个提议中，我们描述了一种新的基于肽的方法来增强BMP-2对海绵的亲和力，并假设这种改善将导致BMP的持续释放，从而改善骨愈合。

DESCRIPTION (provided by applicant): Project Summary/Abstract: There are over 6.3 million fractures each year in the United States of which approximately 700,000 are difficult to heal. The available treatment options for fractures that do not heal or are slow to heal are limited. Bone morphogenetic proteins are growth factors that stimulate new bone production and have received FDA approval for bone fracture repair and spinal fusion. For most clinically approved uses of BMPs, a resorbable collagen sponge is used as the delivery matrix to retain BMP at the site of repair. Low affinity of BMP for the collagen results in the rapid diffusion of BMP and as a result, supraphysiological levels of BMP are required to promote healing. Affinergy develops peptidic macromolecules, interfacial biomaterials (IFBMs) that modulate the critical interface between biological surfaces to initiate and specify interfacial biologic activities. The IFBMs under investigation are composed of different peptide modules that have affinity for BMP and the collagen sponge. A limitation of the technology is the ability to construct many different IFBMs to facilitate rapid screening for subsequent in vivo evaluation. [3+2] cyclo-addition or "click chemistry" will be used to prepare IFBMs since this takes advantage of our modular approach and allows for higher total yields through the coupling of shorter peptides (<25 mers). As a model system we will identify, synthesize, and characterize IFBMs that bind a regenerated collagen sponge and a growth factor for sustained release of Bone Morphogenetic Protein (BMP) to improve bone healing at a fracture site. The specific aims are: Aim 1: Optimize the reaction conditions for coupling peptides of varying molecular weights and sequences using click-chemistry. Aim 2: Screen a library of synthesized IFBMs from peptides identified using phase display and determine binding affinity in vitro to BMP-2. Aim 3: Evaluate the in-vitro ability of BMP-IFBM coated collagen sponges with varying BMP affinities to induce osteoblast differentiation in a C3H10T1/2 mouse mesenchymal cell line. The goal of this SBIR is to demonstrate that IFBMs can be used with a resorbable material to control the delivery of growth factors to bone injuries with the intent of improving healing and clinical outcomes. Project Narrative: There are over 6.3 million fractures each year in the United States of which approximately 700,000 are difficult to heal. Bone morphogenetic proteins (BMPs) are growth factors that stimulate new bone production and have received FDA approval. Currently, a resorbable collagen sponge is used as a delivery matrix for BMP. Low affinity of BMP for the sponge results in poor delivery profiles requiring supraphysiological levels of BMP to promote healing. In this proposal, we describe a novel peptide based approach to enhance the affinity of BMP-2 to the sponge and postulate that this improvement will result in sustained release of BMP resulting in improved bone healing.