三维体系细胞机械力调控、可视化的光学技术设计和应用

Mechanical force has a critical role in many cellular functions, including cell division, gene expression, differentiation and motility. Despite its fundamental importance to cell biology, significant gaps remain in our understanding of the coupling between chemical and mechanical signals. As a first step to understanding mechanotransduction circuits operating within cells, a number of techniques have been developed to investigate the response of individual cells to spatially confined physical perturbations and passively measure cell-generated forces. However, in all of the methods for studying mechanotransduction thus far, cells are cultured on two-dimensional (2D) substrates. And in vivo, cells exist within three-dimensional (3D) environments, and the focal adhesion, cytoskeletal organization and migration of cells in 3D are remarkably different from those of cells cultured on 2D substrates. .Here, we proposed to develop several nanophotonics-based tools to manipulate and investigate cell mechanotransduction in three-dimensional (3D) nanofiber scaffolds. The Optomechanical acatutor (OMA) nanoparticles incorporated with 3D nanofiber scaffolds will allow one to specifically deliver pN forces to cell surface receptors in 3D environments using NIR light. We will study that a variety of 3D cell behaviors, such as cell adhesion, shape and migration are mechanosensitive and can be remotely controlled by our optomechanical switch. Also, we will describe the systematic development of a gold nanoparticle tension probe incorporated 3D scaffolds for visualizing forces exerted by integrin receptors in 3D. For the first time, integrin forces in 3D scaffolds will be quantified with molecular tension probes during in 3D environments. .Combined with 3D force manipulation and 3D tension visualization tools, we will further study how the mechanical force affects the tumor cell adhesion function to maintain intercellular contacts and migrations. These basic knowledge of cell mechanics is related to a variety of major diseases, and will provide new perspectives in biomedical research such as tumor cell invasion and metastasis, stem cell differentiation.

微观机械力在细胞分裂、基因表达、分化和运动等过程中扮演着重要角色。但是由于缺少有效的研究手段，我们目前缺乏对细胞中的机械信号和化学信号之间的耦合机制的理解。为了研究细胞机械信号传导过程，人们开发了多种方法可以在2D基底上对细胞的机械力进行调控和绘制的技术，极大的促进了该领域的发展。但是在真实的3D环境中细胞的形态和迁移过程都显著不同于2D体系。申请人拟发展一套基于纳米光学的3D细胞的机械力学调控和可视化技术，利用光学手段对3D环境中的细胞-ECM界面力学信号进行调控，研究细胞在3D环境下对机械力刺激的响应过程和机制，并将微观机械力学信号转化为荧光信号进行实时观测。结合力学刺激和可视化技术，深入研究3D体系中机械力是如何影响肿瘤细胞黏附、形变以及迁移过程。这些基础知识为在肿瘤细胞入侵转移、干细胞分化等生物医学研究中提供不同视角。

微观机械力在细胞分裂、基因表达、分化和运动等过程中扮演着重要角色。但是由于缺少有效的研究手段，我们目前缺乏对细胞中的机械信号和化学信号之间的耦合机制的理解。为了研究细胞机械信号传导过程，人们开发了多种方法可以在2D基底上对细胞的机械力进行调控和绘制的技术，极大的促进了该领域的发展。但是在真实的3D环境中细胞的形态和迁移过程都显著不同于2D体系。因此，在空间和时间上对细胞机械力进行精准地表征，将可以帮助我们深入认识细胞如何利用微观力学信号诱导和改变相关的生物化学信号，申请人设计了一种新型DNA结构的荧光张力探针并应用于活细胞机械力可视化研究，具有力学量程宽、可逆、单分子灵敏度等优势，并可以用光来控制该探针的机械结构进而达到控制细胞力的功能。通过对细胞迁移过程中integrin介导的机械力进行研究，发现了一类少量、但传递更强机械力的integrin在细胞运动过程扮演着重要角色。此外，除此之外，我们还开发了一个实验程序，实现了水凝胶上细胞分子力的成像，以及实现了3D环境中进行力学调控与成像。这些技术有望成为研究肿瘤细胞迁移、免疫细胞的识别和激活等机械力深度参与的生命过程的重要工具。.