Del Amo C, Borau C, Movilla N, Asín Jesús, García-Aznar J M
Aragón Institute of Engineering Research (I3A), Department of Mechanical Engineering, University of Zaragoza, Zaragoza, Spain.
Integr Biol (Camb). 2017 Apr 18;9(4):339-349. doi: 10.1039/c7ib00022g.
Cell migration is an essential process involved in crucial stages of tissue formation, regeneration or immune function as well as in pathological processes including tumor development or metastasis. During the last few years, the effect of gradients of soluble molecules on cell migration has been widely studied, and complex systems have been used to analyze cell behavior under simultaneous mechano-chemical stimuli. Most of these chemotactic assays have, however, focused on specific substrates in 2D. The aim of the present work is to develop a novel microfluidic-based chip that allows the long-term chemoattractant effect of growth factors (GFs) on 3D cell migration to be studied, while also providing the possibility to analyze the influence of the interface generated between different adjacent hydrogels. Namely, 1.5, 2, 2.5 and 4 mg ml concentrations of collagen type I were alternatively combined with 5, 10 or 50 ng ml concentrations of PDGF and VEGF (as a negative control). To achieve this goal, we have designed a new microfluidic device including three adjacent chambers to introduce hydrogels that allow the generation of a collagen concentration step gradient. This versatile and simple platform was tested by using dermal human fibroblasts embedded in 3D collagen matrices. Images taken over a week were processed to quantify the number of cells in each zone. We found, in terms of cell distribution, that the presence of PDGF, especially in small concentrations, was a strong chemoattractant for dermal human fibroblasts across the gels regardless of their collagen concentration and step gradient direction, whereas the effects of VEGF or collagen step gradient concentrations alone were negligible.
细胞迁移是一个重要过程，涉及组织形成、再生或免疫功能的关键阶段，以及包括肿瘤发展或转移在内的病理过程。在过去几年中，可溶性分子梯度对细胞迁移的影响已得到广泛研究，并且已使用复杂系统来分析细胞在机械化学刺激同时作用下的行为。然而，大多数这些趋化性分析都集中在二维的特定底物上。本研究的目的是开发一种新型的基于微流控的芯片，该芯片能够研究生长因子（GFs）对三维细胞迁移的长期趋化作用，同时还能够分析不同相邻水凝胶之间产生的界面的影响。具体而言，将1.5、2、2.5和4毫克/毫升浓度的I型胶原蛋白与5、10或50纳克/毫升浓度的血小板衍生生长因子（PDGF）和血管内皮生长因子（VEGF，作为阴性对照）交替组合。为实现这一目标，我们设计了一种新的微流控装置，该装置包括三个相邻的腔室，用于引入水凝胶，从而能够产生胶原蛋白浓度阶梯梯度。通过使用嵌入三维胶原蛋白基质中的人皮肤成纤维细胞对这个多功能且简单的平台进行了测试。对一周内拍摄的图像进行处理，以量化每个区域的细胞数量。在细胞分布方面，我们发现，PDGF的存在，尤其是低浓度时，对人皮肤成纤维细胞来说是一种强大的趋化剂，能使其穿过凝胶，而不论凝胶的胶原蛋白浓度和阶梯梯度方向如何，而单独的VEGF或胶原蛋白阶梯梯度浓度的影响可忽略不计。
