Understanding how the mechanical microenvironment affects cardiomyocyte development is crucial to the creation of in vitro models for studying heart physiology and pathophysiology. This knowledge will also facilitate the design of biomaterials and tissue scaffolds utilized in the generation of functional tissue constructs for regenerative medicine and drug screening applications. Here, plasma lithography patterning of elastomeric substrates is exploited for creating microtissues composed of neonatal cardiomyocytes and investigating their attributes in different mechanical microenvironments. Restriction of the cellular outgrowth in line patterns results in cardiomyocytes developing into multicellular clusters and collectively adapting to geometric confinement and substrate stiffness. Immunofluorescence microscopy, video microscopy, and force spectroscopy show that the size and shape of the cardiomyocyte clusters, as well as sarcomere length, fiber alignment, beating amplitude, and beating frequency of the cardiomyocytes, are regulated by the microenvironmental cues. Computational analysis reveals that the mechanical stress at the cluster-substrate interface strongly correlates with the characteristics of the cardiomyocytes. Taken together, our results underscore a collective mechanoadaptation scheme in cardiac development.
Keywords: cardiomyocyte; cell microenvironment; cell patterning; mechanoregulation; plasma lithography.