基于数字体积图像相关的高性能三维细胞生长力显微镜技术研究

Quantifying spatial-temporal dynamics of 3D cell growth forces is crucial for investigating the complex mechano-transduction pathways as well as the interactions between single cells and 3D matrix around them. This project first plans to fabricate biocompatible hydrogels which can not only be used to carry out 3D cell culture but also facilitate the tracking of hydrogel deformation induced by cell activities. In this way, this project will establish an experimental platform for mechanical interplay between cells and the corresponding matrix micro-environments. Based on the microscope, this project will subsequently explore a feasible way to obtain the high-quality cell-matrix images in combination with high-efficiency 3D image deconvolution strategy. Further, this project will develop a set of digital volume correlation (DVC) algorithms specific for local large-deformation measurement by introducing some appropriate weighted window function into the traditional DVC algorithms. Finally, this project will develop a stable and reliable technique of 3D cell growth force recovery with the aid of a nonlinear large-deformation finite element model characterizing the mechanical relationship of cell growth forces and the resultant matrix deformations. This research work provides an accurate and reliable measurement tool for deeply studying mechano-biological mechanism related to cell interactions with 3D extracellular micro-environments.

精准测量单细胞三维生长力的时空变化规律是定量开展细胞与三维基质物理力学相互作用及其诱发复杂力信号转导通路研究的必要前提和基础。本项目拟通过合成生物相容性好，既适合细胞体外三维培养又利于数字图像变形测量的荧光-水凝胶基质材料，构建细胞与三维基质物理力学相互作用研究实验体系；依托荧光显微镜成像技术，研究优化对细胞与三维基质相互作用进行长时间、高时空分辨率显微荧光成像的可行实验方案和相应的图像后处理方法；结合权重窗函数思想，着重发展适于大变形测量的数字体积图像相关测量新算法；在此基础上，基于非线性大变形有限元方法构建细胞与三维基质相互作用的力学模型，发展稳定可靠、高时空分辨率的三维细胞生长力反演技术，为三维细胞力学生物学研究提供精准可靠的实验技术手段。

本项目聚焦于单细胞三维生长力时空变化的精准表征这一重要科学问题，从材料合成、三维图像获取、算法开发及理论模型推导等方面，对高性能三维细胞生长力显微镜技术的发展进行了系统地研究。本项目合成了多种生物相容性良好、力学性质可调的水凝胶基质材料，不仅为细胞力学相关研究提供了条件，也为生物医学和柔性电子学等领域的应用提供了新的可能性。通过采用光片显微镜对细胞进行三维荧光成像，并结合解卷积、细胞轮廓提取等后处理方法，有效提高了所得图像的空间分辨率和信噪比。基于项目研究过程中的实验发现，本项目设计了一系列复杂的物理力学细胞外基质微环境，对细胞响应的生物力学和力学生物学机制进行了深入探讨，所得结果在阐明胚胎发育过程、指导研发癌症治疗新方法等方面均具有潜在意义。为了提高位移测量的精准性，本项目分别开发了基于自适应子区/单元尺寸选取的数字体积相关方法和无网格数字体积相关方法，作为非线性大变形位移场定量表征的有效途径，在生物力学、航空航天、地质监测等领域均具有良好的应用前景。通过引入超弹性本构及截断总体最小二乘正则化方法，发展了精准高效、稳定鲁棒的三维细胞生长力反演技术，为三维细胞力学生物学研究提供了可靠的实验平台。此外，本项目还构建了可描述细胞-基质三维相互作用的理论模型，揭示了三维细胞外基质刚度对细胞生理/病理状态的调节作用。