Ji Jiaying, Ren Xiang, Zorlutuna Pinar
Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, IN 46556, USA.
Micromachines (Basel). 2021 Oct 31;12(11):1351. doi: 10.3390/mi12111351.
Cardiomyocytes (CMs) and fibroblast cells are two essential elements for cardiac tissue structure and function. The interactions between them can alter cardiac electrophysiology and thus contribute to cardiac diseases, such as arrhythmogenesis. One possible explanation is that fibroblasts can directly affect cardiac electrophysiology through electrical coupling with CMs. Therefore, detecting the electrical activities in the CM-fibroblast network is vital for understanding the coupling dynamics among them. Current commercialized platforms for studying cardiac electrophysiology utilize planar microelectrode arrays (MEAs) to record the extracellular field potential (FP) in real-time, but the prearranged electrode configuration highly limits the measurement capabilities at specific locations. Here, we report a custom-designed MEA device with a novel micropatterning method to construct a controlled network of neonatal rat CMs (rCMs) and fibroblast connections for monitoring the electrical activity of rCM-fibroblast co-cultures in a spatially controlled fashion. For the micropatterning of the co-culture, surface topographical features and mobile blockers were used to control the initial attachment locations of a mixture of rCMs and fibroblasts, to form separate beating rCM-fibroblast clusters while leaving empty space for fibroblast growth to connect these clusters. Once the blockers are removed, the proliferating fibroblasts connect and couple the separate beating clusters. Using this method, electrical activity of both rCMs and human-induced-pluripotent-stem-cell-derived cardiomyocytes (iCMs) was examined. The coupling dynamics were studied through the extracellular FP and impedance profile recorded from the MEA device, indicating that the fibroblast bridge provided an RC-type coupling of physically separate rCM-containing clusters and enabled synchronization of these clusters.
心肌细胞（CMs）和成纤维细胞是心脏组织结构和功能的两个基本要素。它们之间的相互作用会改变心脏电生理，进而导致诸如心律失常等心脏疾病。一种可能的解释是，成纤维细胞可通过与心肌细胞的电耦合直接影响心脏电生理。因此，检测心肌细胞-成纤维细胞网络中的电活动对于理解它们之间的耦合动力学至关重要。当前用于研究心脏电生理的商业化平台利用平面微电极阵列（MEAs）实时记录细胞外场电位（FP），但预先安排的电极配置极大地限制了在特定位置的测量能力。在此，我们报告一种定制设计的MEA装置，其采用一种新颖的微图案化方法构建新生大鼠心肌细胞（rCMs）和成纤维细胞连接的可控网络，以便以空间可控的方式监测rCM-成纤维细胞共培养物的电活动。对于共培养物的微图案化，利用表面形貌特征和移动阻滞剂来控制rCMs和成纤维细胞混合物的初始附着位置，形成单独跳动的rCM-成纤维细胞簇，同时留出成纤维细胞生长的空间以连接这些簇。一旦去除阻滞剂，增殖的成纤维细胞就会连接并耦合这些单独跳动的簇。使用这种方法，研究了rCMs和人诱导多能干细胞衍生的心肌细胞（iCMs）的电活动。通过从MEA装置记录的细胞外FP和阻抗谱研究了耦合动力学，表明成纤维细胞桥提供了物理上分离的含rCM簇的RC型耦合，并实现了这些簇的同步。
