Mechanical and Materials Engineering, School of Biomedical, Materials and Mechanical Engineering (SBMME), College of Engineering and Computing, Florida International University, 10555 West Flagler Street, Miami, FL 33174, USA.
Department of Physics, Florida International University, Miami, FL 33174, USA.
Nanoscale. 2023 Jun 23;15(24):10360-10370. doi: 10.1039/d3nr01553j.
Understanding myocytes' spatiotemporal mechanical behavior and viscoelasticity is a long-standing challenge as it plays a critical role in regulating structural and functional homeostasis. To probe the time-dependent viscoelastic behaviors of cardiomyocytes with cross-linked polymer networks, we measure stem cell-derived cardiomyocyte's (hiPSC-CM) deformation, adhesion, and contractility using atomic force microscopy (AFM) nanoindentation, fluidic micropipette, and digital image correlation (DIC). Our results show a cytoplasm load of 7-14 nN, a de-adhesion force of 0.1-1 nN, and an adhesion force between two hiPSC-CMs of 50-100 nN with an interface energy of 0.45 pJ. Based on the load-displacement curve, we model its dynamic viscoelasticity and discover its intimate associations with physiological properties. Cell detaching and contractile modeling demonstrate cell-cell adhesion and beating related strains manifesting viscoelastic behavior, highlighting viscoelasticity plays the primary role in governing hiPSC-CM spatiotemporal mechanics and functions. Overall, this study provides valuable information about the mechanical properties, adhesion behaviors, and viscoelasticity of single hiPSC-CM, shedding light on mechanical-structure relationships and their dynamic responses to mechanical stimuli and spontaneous contraction.
了解心肌细胞的时空力学行为和粘弹性是一个长期存在的挑战，因为它在调节结构和功能的动态平衡中起着至关重要的作用。为了研究具有交联聚合物网络的心肌细胞的时变粘弹性行为，我们使用原子力显微镜（AFM）纳米压痕、流体微管和数字图像相关（DIC）技术测量干细胞衍生的心肌细胞（hiPSC-CM）的变形、粘附和收缩性。我们的结果显示细胞质负荷为 7-14 nN，去粘附力为 0.1-1 nN，两个 hiPSC-CM 之间的粘附力为 50-100 nN，界面能为 0.45 pJ。基于加载-位移曲线，我们对其动态粘弹性进行建模，并发现其与生理特性密切相关。细胞分离和收缩建模表明细胞-细胞粘附和跳动相关应变表现出粘弹性行为，突出了粘弹性在控制 hiPSC-CM 的时空力学和功能方面起着主要作用。总的来说，这项研究提供了关于单个 hiPSC-CM 的机械特性、粘附行为和粘弹性的有价值的信息，揭示了机械结构关系及其对机械刺激和自发收缩的动态响应。
