成骨细胞重塑胶原基聚电解质膜机制及其在骨基质形成中的作用研究

在生物材料设计中需充分考虑细胞与材料的相互作用。细胞接受周围基质信号刺激，对其微环境进行重塑的过程在组织形成中至关重要。我们前期研究发现，成骨细胞不仅可以在硫酸软骨素/I型胶原聚电解质膜上粘附、伸展，还能将膜内胶原组装成特定纤维阵列结构，提示成骨细胞可重塑胶原基聚电解质膜，但具体机制及其对骨基质形成的影响并不明确。本项目拟采用层层自组装技术仿生构建不同硬度的胶原基聚电解质膜，利用荧光染色结合高分辨活细胞显微成像系统等技术考察成骨细胞对各聚电解质膜的重塑情况，明确膜硬度对重塑的影响；并通过研究重塑过程中成骨细胞对聚电解质膜力学组装及酶解作用的影响，阐明成骨细胞对聚电解质膜的重塑机制；最后仿生模拟体内骨形成条件，通过研究骨有机基质的分泌、组装及钙化，揭示成骨细胞重塑胶原基聚电解质膜在引导骨基质形成中的作用。项目的成功将为聚电解质膜材料设计提供新的思路，为探讨材料诱导组织再生能力提供重要依据。

The comprehensive consideration regarding dynamic interaction between cells and material is highly demanded by designing ideal biomaterials. Cells accept distinct signals from the surrounding matrix and in turn, they actively regulate microenvironment to develop tissues. We have found previously that osteoblasts were not only able to adhere onto the multilayer surface assembling from type I collagen and chondroitin sulfate but also organize the collagen into a specific fibrillar-like array pattern, suggesting the remodeling of polyelectrolyte multilayers. Yet, the potential mechanism underlying the remodeling activity mediated by osteoblasts and its role in bone matrix formation is unclear. Here, the layer by layer method is applied to build up collagen based-polyelectrolyte multilayers varying in stiffness, and the remodeling ability of osteoblasts towards the multilayer system is studied by using a DeltaVision high resolution microscopy system, combined with fluorescent staining, to investigate the effect of substrate stiffness on remodeling process. To clarify the potential mechanism involved, we will further study the mechanical assembly and enzymatic changes of substrates in the process of remodeling. Finally, we attempt to monitor matrix secretion and its calcification to reveal the role of multilayer remodeling caused by osteoblasts during bone matrix formation. The success of this project will provide new insights into biomaterial design and sound evidence on guiding tissue regeneration by biomaterials.