González-Lana Sandra, Randelovic Teodora, Ciriza Jesús, López-Valdeolivas María, Monge Rosa, Sánchez-Somolinos Carlos, Ochoa Ignacio
Tissue Microenvironment (TME) Lab. Aragón Institute of Engineering Research (I3A), University of Zaragoza, C/ Mariano Esquillor s/n, 500018 Zaragoza, Spain.
BEONCHIP S.L., CEMINEM, Campus Río Ebro. C/ Mariano Esquillor Gómez s/n, 50018 Zaragoza, Spain.
Lab Chip. 2023 May 16;23(10):2434-2446. doi: 10.1039/d3lc00075c.
The tissue microenvironment plays a crucial role in tissue homeostasis and disease progression. However, the simulation has been limited by the lack of adequate biomimetic models in the last decades. Thanks to the advent of microfluidic technology for cell culture applications, these complex microenvironments can be recreated by combining hydrogels, cells and microfluidic devices. Nevertheless, this advance has several limitations. When cultured in three-dimensional (3D) hydrogels inside microfluidic devices, contractile cells may exert forces that eventually collapse the 3D structure. Disrupting the compartmentalisation creates an obstacle to long-term or highly cell-concentrated assays, which are extremely relevant for multiple applications such as fibrosis or ischaemia. Therefore, we tested surface treatments on cyclic-olefin polymer-based microfluidic devices (COP-MD) to promote the immobilisation of collagen as a 3D matrix protein. Thus, we compared three surface treatments in COP devices for culturing human cardiac fibroblasts (HCF) embedded in collagen hydrogels. We determined the immobilisation efficiency of collagen hydrogel by quantifying the hydrogel transversal area within the devices at the studied time points. Altogether, our results indicated that surface modification with polyacrylic acid photografting (PAA-PG) of COP-MD is the most effective treatment to avoid the quick collapse of collagen hydrogels. As a proof-of-concept experiment, and taking advantage of the low-gas permeability properties of COP-MD, we studied the application of PAA-PG pre-treatment to generate a self-induced ischaemia model. Different necrotic core sizes were developed depending on initial HCF density seeding with no noticeable gel collapse. We conclude that PAA-PG allows long-term culture, gradient generation and necrotic core formation of contractile cell types such as myofibroblasts. This novel approach will pave the way for new relevant co-culture models where fibroblasts play a key role such as wound healing, tumour microenvironment and ischaemia within microfluidic devices.
组织微环境在组织稳态和疾病进展中起着至关重要的作用。然而，在过去几十年中，由于缺乏足够的仿生模型，相关模拟受到了限制。得益于用于细胞培养应用的微流控技术的出现，通过结合水凝胶、细胞和微流控设备，可以重现这些复杂的微环境。尽管如此，这一进展仍有若干局限性。当在微流控设备内的三维（3D）水凝胶中培养时，收缩性细胞可能会施加力，最终导致3D结构坍塌。破坏分隔会给长期或高细胞浓度检测带来障碍，而这些检测对于诸如纤维化或缺血等多种应用极为重要。因此，我们测试了基于环烯烃聚合物的微流控设备（COP-MD）上的表面处理，以促进作为3D基质蛋白的胶原蛋白的固定。于是，我们比较了COP设备中用于培养包埋在胶原蛋白水凝胶中的人心脏成纤维细胞（HCF）的三种表面处理方法。我们通过在研究的时间点量化设备内水凝胶的横向面积来确定胶原蛋白水凝胶的固定效率。总的来说，我们的结果表明，COP-MD的聚丙烯酸光接枝（PAA-PG）表面改性是避免胶原蛋白水凝胶快速坍塌的最有效处理方法。作为概念验证实验，并利用COP-MD的低气体渗透性，我们研究了PAA-PG预处理在生成自诱导缺血模型中的应用。根据初始HCF接种密度形成了不同大小的坏死核心，且未观察到明显的凝胶坍塌。我们得出结论，PAA-PG允许长期培养、梯度生成以及诸如肌成纤维细胞等收缩性细胞类型的坏死核心形成。这种新方法将为新的相关共培养模型铺平道路，在这些模型中，成纤维细胞在微流控设备内的伤口愈合、肿瘤微环境和缺血等方面发挥关键作用。
