Substrate Independent, Spatially Resolved, Stable Polymer Coatings for Studying Human Mesenchymal Stem Cells (hMSCs)

该奖项由材料研究部的生物材料计划颁发，是一项为期三年的综合研究、教育和推广聚合物涂层的计划，用于研究人类间充质干细胞(HMSCs)。该奖项由材料研究部的聚合物项目共同资助。早期的研究表明，hMSC的表型受到来自自然细胞微环境的配体的强烈影响，包括细胞粘附肽、肝素结合肽和生长因子模拟肽。这一建议是以聚乙二醇共聚物为基础的聚合物涂层，其可交联性基团最多为10%，可交联成30 nm的垫子用于多肽的固定化。这些垫的化学定义是为了在较长的时间内稳定地呈现两种可能的成骨多肽，并深入探讨对hMSC向成骨细胞分化的影响。这些含有多肽的聚合物涂层呈现出稳定的疏细胞板层，因此可以真正研究相关多肽在成骨分化的整个过程中对hMSCs的影响。重要的是，这些涂层是可以应用于几乎任何底层衬底的薄膜，这将对细胞培养研究和未来生物医学设备的设计产生广泛影响。由于薄膜的性质，拟议使用的X射线光电子能谱将精确地定量聚合物涂层上呈现的多肽。此外，这项建议将研究首次系统分析化学定义的、纳米尺度的生长因子受体结合配体，鉴于受体二聚化/聚集在几乎所有生长因子信号系统中的重要性，它可能会导致广泛的影响。这一提议在技术上的更广泛影响将是开发一种新的超薄生物材料涂层，具有一套独特的干细胞生长特性。为了清楚地了解微环境信号对干细胞行为的影响，迫切需要向干细胞呈现特定信号和复杂信号组合的实验系统。建议的平台可能会导致细胞生物学家普遍广泛使用建议的方法。最终，这一系列研究可能导致识别促进谱系特异性干细胞分化的信号，从而开发和优化在体外和体内促进干细胞分化的底物。更广泛地说，所提出的可适应性和化学可剪裁的薄膜将适用于细胞生物学中的广泛的基本问题，其中需要稳定的、可控的多肽配体的呈现。作为这笔赠款的一部分，该项目将：1)在两个系开发两门跨学科课程，一个以材料科学与工程为基础，另一个以生物医学工程为基础；2)通过开发干细胞和组织工程的实践展览，为科学和社会媒体课程提供案例研究材料，开展传播和外联活动；以及3)招募和指导女性和代表性较低的少数族裔研究生和本科生参加研究活动。

This award by the Biomaterials program in the Division of Materials Research is a three-year plan of integrated research, education, and outreach on a polymeric coating for studying human mesenchymal stem cells (hMSCs). This award is cofunded by the Polymer program in the Division of Materials Research. Earlier studies strongly indicate that hMSC phenotype is strongly influenced by ligands derived from the natural cellular microenvironment, including cell adhesion peptides, heparin-binding peptides, and growth factor-mimetic peptides. This proposal is to develop polymer coatings based on copolymers of poly(ethylene glycol) with at most 10% of crosslinkable groups, which can be crosslinked into 30 nm mats for immobilization of peptides. These mats are chemically-defined for stable presentation of two putative pro-osteogenic peptides over an extended timeframe, and to explore in depth the effects on hMSC differentiation into osteoblasts. These polymer coatings with peptides present a stable cytophobic slate, and hence one can truly investigate the effect of the relevant peptides on hMSCs during the entire time course of osteogenic differentiation. Importantly, these coatings are thin films that can be applied to virtually any underlying substrate, which will lead to broad impact on cell culture studies and future design of biomedical devices. Because of the thin-film nature, the proposed use of X-ray photoelectron spectroscopy will quantify precisely the peptides presented on the polymer coatings. Further, this proposal will study the first systematic analysis of chemically defined, nanometer-scale presentation of a growth factor-receptor binding ligand, and it may lead to broad impact in view of the importance of receptor dimerization/clustering in virtually all growth factor signaling systems. The technological broader impact of this proposal would be in developing a new class of ultra-thin biomaterial coatings with unique set of properties for stem cell growth. In order to clearly understand the effects of micro environmental signals on stem cell behavior, there is a critical need for experimental systems that present specific signals, and complex signal combinations, to stem cells. The proposed platform may lead to widespread use of the proposed approaches by cell biologists in general. Ultimately, this line of research could result in identification of signals that promote lineage-specific stem cell differentiation, leading to development and optimization of substrates that promote stem cell differentiation in vitro and in vivo. More generally, the proposed adaptable and chemically tailorable thin films would be applicable to a broad range of fundamental questions in cell biology in which stable, controlled presentation of peptide ligands is desirable. As part of this grant, this project will: 1) develop Interdisciplinary Curriculum Development of two courses in two departments, one based in Materials Science & Engineering, and the second one based in Biomedical Engineering; 2) carry out dissemination and outreach activities by the development of hands-on exhibits on Stem Cells and Tissue Engineering that would provide case study materials for a Science and Social Media course; and 3) recruit and mentor female and underrepresented minority graduate and undergraduate students in research activities.