Measuring the Contractile Forces of Human Induced Pluripotent Stem Cell Derived Cardiomyocytes With Arrays of Microposts

Abstract

Human stem cellderived cardiomyocytes hold promise for heart repair, disease modeling, drug screening, and for studies of developmental biology. All of these applications can be improved by assessing the contractility of cardiomyocytes at the single cell level. We have developed an in vitro platform for assessing the contractile performance of stem cellderived cardiomyocytes that is compatible with other common endpoints such as microscopy and molecular biology. Human induced pluripotent stem cellderived cardiomyocytes (hiPSCCMs) were seeded onto elastomeric micropost arrays in order to characterize the contractile force, velocity, and power produced by these cells. We assessed contractile function by tracking the deflection of microposts beneath an individual hiPSCCM with optical microscopy. Immunofluorescent staining of these cells was employed to assess their spread area, nucleation, and sarcomeric structure on the microposts. Following seeding of hiPSCCMs onto microposts coated with fibronectin, laminin, and collagen IV, we found that hiPSCCMs on laminin coatings demonstrated higher attachment, spread area, and contractile velocity than those seeded on fibronectin or collagen IV coatings. Under optimized conditions, hiPSCCMs spread to an area of approximately 420 خ¼m2, generated systolic forces of approximately 15 nN/cell, showed contraction and relaxation rates of 1.74 خ¼m/s and 1.46 خ¼m/s, respectively, and had a peak contraction power of 29 fW. Thus, elastomeric micropost arrays can be used to study the contractile strength and kinetics of hiPSCCMs. This system should facilitate studies of hiPSCCM maturation, disease modeling, and drug screens as well as fundamental studies of human cardiac contraction.