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

该奖项由材料研究部生物材料项目颁发，是一项为期三年的综合研究、教育和推广计划，旨在研究用于研究人类间充质干细胞（hMSCs）的聚合物涂层。该奖项由材料研究部的聚合物项目共同资助。早期的研究强烈表明，hMSC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、肝素结合肽和模拟生长因子肽。该方案是开发基于聚乙二醇共聚物的聚合物涂层，其交联基团最多为10%，可交联成30 nm的垫，用于固定肽。这些垫子是化学定义的，用于在较长时间内稳定呈现两种推定的促成骨肽，并深入探索hMSC向成骨细胞分化的影响。这些带有多肽的聚合物涂层提供了一个稳定的细胞排斥板，因此人们可以真正研究相关肽在成骨分化的整个过程中对hMSCs的影响。重要的是，这些涂层是薄膜，几乎可以应用于任何底层基质，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的影响。由于薄膜的性质，建议使用x射线光电子能谱可以精确地量化聚合物涂层上呈现的肽。此外，该提案将首次系统分析生长因子受体结合配体的化学定义，纳米尺度的呈现，鉴于受体二聚化/聚类在几乎所有生长因子信号系统中的重要性，它可能会产生广泛的影响。这项提议在技术上的广泛影响将是开发一种新的超薄生物材料涂层，这种涂层具有干细胞生长的独特性能。为了清楚地了解微环境信号对干细胞行为的影响，迫切需要能够向干细胞提供特定信号和复杂信号组合的实验系统。所提出的平台可能导致细胞生物学家普遍使用所提出的方法。最终，这条研究路线可能导致识别促进谱系特异性干细胞分化的信号，从而开发和优化促进体外和体内干细胞分化的底物。更一般地说，提出的适应性和化学上可定制的薄膜将适用于细胞生物学中广泛的基本问题，其中稳定，控制肽配体的呈现是可取的。作为本基金的一部分，本项目将：1)开发两个系的两门跨学科课程开发，一门基于材料科学与工程，另一门基于生物医学工程；2)通过开发干细胞和组织工程的实践展览开展传播和外展活动，为科学和社会媒体课程提供案例研究材料；3)在研究活动中招募和指导女性和少数民族研究生和本科生。

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.