Microenvironmental control of adult stem cell differentiation: Influence of biochemical ECM composition, ECM stiffness and electric fields

细胞发育强烈依赖于由细胞微环境提供的许多生化和物理信号。传统上，体外实验研究集中在一种信号类型的影响，并没有忠实地概括在体内占主导地位的复杂和动态的信号。然而，越来越清楚的是，各种信号-生物化学和物理性质-相互作用强烈，特别是这些刺激的组合是必不可少的终端分化。因此，本项目的目的是研究多种生物化学（基质成分）和生物物理（基质硬度，电场）信号在其对人MSC分化行为的综合影响中的相互作用。特别地，将设计并评估基于胶原蛋白与所选GAG衍生物组合的掺入各种ECM分子的混合夹心凝胶在MSC中引发差异反应的功效。此外，凝胶的硬度将在宽范围内定制，以匹配天然组织的顺应性，例如脂肪（~ 2 kPa）、软骨（~ 20 kPa）和预钙化骨（~ 40 kPa）。此外，通过电场的额外应用，该项目旨在确定最适合成骨分化的参数集，并初步了解信号通路如何受到这种组合刺激的影响。总的来说，该项目将为细胞分化过程提供新的见解。理解这种复杂的细胞-材料-相互作用将为设计和开发新型组织工程构建体创造新的机会。

Cellular development is strongly dependent on numerous biochemical and physical signals provided by the cellular microenvironment. Traditionally, in vitro experimental studies concentrate on the influence of one signaling type and do not faithfully recapitulate the complex and dynamic signaling that predominates in vivo. However, it is increasingly clear that various signals - both of biochemical and physical in nature - interact strongly with each other and especially the combination of these stimuli is essential for terminal differentiation. Thus, the aim of this project is to study the interaction of multiple biochemical (matrix composition) and biophysical (matrix stiffness, electric fields) signals in their combined effects on differentiation behavior of human MSCs. In particular, a hybrid-sandwich gel incorporating various ECM molecules, based on collagen in combination with selected GAG-derivatives, will be designed and evaluated for its efficacy in eliciting differential response in MSCs. Moreover, the stiffness of the gel will be tailored over a wide range, to match the compliance of native tissues such as adipose (~ 2 kPa), cartilage (~ 20 kPa) and pre-calcified bone (~ 40 kPa). Further, by the additional application of electric field this project intent to determine the parameters sets best suited for osteogenic differentiation and to gain a first understanding of how signaling pathways are influenced by such combined stimulations. Overall, this project will provide new insights into the cellular differentiation process. Understanding such complex cell-material-interactions will create new opportunities for designing and developing novel tissue engineering constructs.