Microgroove and Cyclic Stretch-Based Stem Cell Gym Enhance Maturation of Human iPSC-Derived Cardiomyocytes

Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are an important source of engineered cardiac tissue; however, the immaturity of their structure and function considerably limits their application. During heart development, cardiomyocytes gradually align in parallel and generate contractile force, which hints that the orderly alignment and dynamic stretch of cells are essential for hiPSC-CM maturation. Our findings indicate that hiPSC-CMs exhibit increased cellular elongation, sarcomere length, and expression of cardiac troponin T (cTnT) when cultured on 10-50 μm microgroove substrates. Additionally, myocardial connexin expression and mitochondrial occupancy were enhanced on 10 and 30 μm microgroove substrates. Furthermore, cyclic stretching with 20 and 30 μm microgroove substrates further augmented the expression of cTnT and MLC2v, as well as sarcomere length and mitochondrial occupancy in hiPSC-CMs. Importantly, the action potential recordings demonstrated the electrophysiological properties of hiPSC-CMs were improved when subjected to cyclic stretching with 20 and 30 μm microgroove substrates. Our study suggests that coordinated microgroove and cyclic stretch act as a stem cell gym to promote the structural, metabolic, and electrophysiological maturation of hiPSC-CMs, thereby enhancing their utility in cardiac regeneration and disease modeling.