Collagen microstructure is closely related to the mechanical properties of tissues and affects cell migration through the extracellular matrix. To study these structures, three-dimensional (3D) in vitro collagen-based gels are often used, attempting to mimic the natural environment of cells. Some key parameters of the microstructure of these gels are fiber orientation, fiber length, or pore size, which define the mechanical properties of the network and therefore condition cell behavior. In the present study, an automated tool to reconstruct 3D collagen networks is used to extract the aforementioned parameters of gels of different collagen concentration and determine how their microstructure is affected by the presence of cells. Two different experiments are presented to test the functionality of the method: first, collagen gels are embedded within a microfluidic device and collagen fibers are imaged by using confocal fluorescence microscopy; second, collagen gels are directly polymerized in a cell culture dish and collagen fibers are imaged by confocal reflection microscopy. Finally, we investigate and compare the collagen microstructure far from and in the vicinities of MDA-MB 23 cells, finding that cell activity during migration was able to strongly modify the orientation of the collagen fibers and the porosity-related values.

中文翻译：

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基于图像的3D胶原蛋白网络表征和嵌入式细胞的作用。

胶原蛋白的微结构与组织的机械特性密切相关，并影响细胞通过细胞外基质的迁移。为了研究这些结构，经常使用三维（3D）体外胶原蛋白凝胶，试图模仿细胞的自然环境。这些凝胶的微结构的一些关键参数是纤维取向，纤维长度或孔径，它们定义了网络的机械性能并因此调节了细胞的行为。在本研究中，用于重建3D胶原蛋白网络的自动化工具用于提取不同胶原蛋白浓度的凝胶的上述参数，并确定细胞的存在如何影响其微观结构。提出了两个不同的实验来测试该方法的功能：首先，将胶原蛋白凝胶包埋在微流体装置中，并使用共聚焦荧光显微镜对胶原蛋白纤维成像；第二，将胶原蛋白凝胶直接在细胞培养皿中聚合，并通过共聚焦反射显微镜对胶原蛋白纤维成像。最后，我们调查并比较了MDA-MB 23细胞附近和附近的胶原微结构，发现迁移过程中的细胞活性能够强烈地改变胶原纤维的方向和孔隙率相关值。