Evaluation of Extracellular Matrix Influence to Beat Synchronicity of iPSC-derived Cardiomyocyte-NHC Fibroblast 3D Tissues Using Image Correlation Analysis

Multicellular 3D cardiac microtissues composed of induced pluripotent stem cell (iPSC) derived cardiomyocytes and normal human cardiac fibroblasts (NHCFs) with different contractile performances are presented in this work. The cells were coated with fibronectin-gelatin nanofilm or collagen and then assembled using the developed cell accumulation technique to produce the multi-layered 3D tissues. The mixing ratio of NHCFs was adjusted to 0%, 25%, 50%, and 75% (iPS-CM100, iPS-CM75, iPS-CM50, iPS-CM25) of the total cell number. Using the image correlation analysis (Fig 1a-d), a non-invasive method, the effect of the amount of NHCF and the type of extra cellular matrix (ECM) coating used in the developed technique was determined. After 4 days of incubation, it was observed that the microtissue formed from the cells coated with collagen and with 25% NHCF had the best performance (Fig. 1e-f). However, further tests are still needed to determine if a lower amount of NHCF will have better performance and if it will be compatible with the host myocardium. Other tests are still needed to be done to determine the relationship of the histology to the observed contractile behavior. In addition, the presented data can be utilized in tuning the contractile behavior of the tissue by changing the ratio of iPS-CM and NHCF and cell surface coating depending on the desired behavior. With this, an alternative method for analyzing the engineered tissue and assessing the derived parameters were formulated which can be helpful in realizing the ideal cardiac tissue for transplant.