Combinatorial Metal Oxide Substrates to Enhance Osteogenic Stem Cell Functions

描述(由申请者提供)：本项目的总体目标是为基于组合材料科学的生物材料筛选策略奠定基础。这种方法将为基材提供一系列表面属性和成分的细微变化。这些新材料配方的有效性将通过使用细胞培养模型并通过系统研究生物材料表面的元素组成、表面化学和形貌对间充质干细胞(MSC)分化和与新骨形成相关的功能的影响来确定。中心假设是材料基质的金属氧化物表面调节被吸附的蛋白质的类型、分布和构象，这些蛋白质直接和调节随后的细胞相互作用和与新组织形成相关的功能。具体目标1：开发以钛为基础的金属氧化物衬底，该衬底含有用作植入材料的其他三种金属的梯度。通过等离子体增强化学气相沉积的方法进行退火，可以利用溅射到钛衬底上的不同厚度的薄膜产生浓度梯度。特定目标2：确定特定的血清和/或ECM黏附蛋白的类型、分布和构象，如I型胶原、纤维连接蛋白、层粘连蛋白和玻璃体连接蛋白，吸附在与特定目标1相关的研究活动制备的新型材料基质上。假设在贴壁后，MSCs的迁移将受到表面梯度的影响，在底物表面已经吸附了特定蛋白质的区域，最重要的是，显示出适当的结构域，促进后续的细胞黏附和与新组织形成相关的功能。拟议的研究从根本上不同于过去和目前的方法，因为它将开发一种新的工艺，允许对各种化学计量组合的多种材料配方进行高通量测试。这项研究有望实现以下目标：(1)阐明蛋白质在新型底物上的吸附和黏附以及细胞的功能；(2)建立这些金属氧化物底物作为高通量细胞相容性评估平台的潜力。 与公共健康相关：随着美国假体植入物市场每年约10亿美元的规模，并以每年10%的速度增长，假体植入物的骨整合和寿命的任何改善都将产生巨大的经济影响，特别是如果考虑到在髋关节置换等手术中高达30%的假体没有表现出适当的骨整合。该项目旨在利用最先进的表面表征和基因表达技术，通过研究材料表面性质和蛋白质吸附对成骨间充质干细胞行为的影响，来增加筛选出的用于改善骨整合的候选生物材料的数量。

DESCRIPTION (provided by applicant): The overall objective of this project is to develop a foundation for a biomaterial screening strategy based on combinatorial materials science. This approach will provide substrates with a range of subtle changes in surface properties and composition. The efficacy of these novel material formulations will be determined in vitro using cell-culture models and by conducting a systematic investigation of the effects of the elemental composition of the biomaterial surface chemistry and topography on mesenchymal stem cell (MSC) differentiation and functions pertinent to new bone formation. The central hypothesis is that the metal oxide surface of the material substrate modulates the type, distribution and conformation of adsorbed proteins, these proteins direct and modulate subsequent cell interaction and function pertinent to new tissue formation. Specific Aim 1: Develop metal oxide substrates based on titanium that contain gradients of three other metals used as implant materials. It is hypothesized that, annealing by plasma-enhanced chemical vapor deposition, will generate concentration gradients using thin films of variable thickness sputtered onto Ti substrates. Specific Aim 2: Determine the type, distribution and conformation of select serum and/or ECM adhesive proteins such as collagen type I, fibronectin, laminin, and vitronectin, adsorbed onto the novel material substrates prepared by the research activities pertinent to Specific Aim 1. Specific Aim 3: Assess the osteogenic differentiation of MSCs onto the nanostructured substrates. It is hypothesized that following adhesion, MSCs migration will be affected by the surface gradients to regions on the substrate surface where select proteins had adsorbed and, most importantly, exhibit appropriate domains which promote subsequent cell adhesion and functions pertinent to new tissue formation. The proposed research is fundamentally different from past and current approaches in that it will develop a new process that will allow high-throughput testing of multiple material formulations of various stoichiometric combinations. This research is expected to achieve the following: (1) elucidate aspects of protein adsorption and adhesion and function of cells on the novel substrates; and (2) establish the potential of these metal oxide substrates as a high-throughput cytocompatibility assessment platform. PUBLIC HEALTH RELEVANCE: With a U.S. Prosthetic Implant market of about $1 billion a year and growing at a rate of 10% a year, any improvement in osseointegration and life of the prosthetic implant will have a drastic economic effect, especially if one takes into consideration that up to 30% of the implants in procedures such as hip replacement do not show appropriate osseointegration. The proposed project aims to improve the number of candidate biomaterials screened for improved osseointegration by investigating the effect of the material surface properties and protein adsorption on osteogenic mesenchymal stem cell behavior, using state of the art surface characterization and gene expression technologies.