Dynamic AFM elastography reveals phase dependent mechanical heterogeneity of beating cardiac myocytes.
We developed a novel atomic force microscope (AFM) indentation technique for mapping spatiotemporal stiffness of spontaneously beating neonatal rat cardiac myocytes. Cells were indented at a rate close but unequal to their contractile frequency. Resultant apparent elastic modulus cycled at a predictable envelope frequency between a systolic value of 26.2 +/- 5.1 kPa and a diastolic value of 7.8 +/- 4.1 kPa. In cells probed along their axis, spatial heterogeneity of systolic stiffness correlated with the sarcomeric structure of underlying myofibrils. Treatment with blebbistatin eliminated contractile activity and resulted in a uniform modulus of 6.5 +/- 4.8 kPa. The technique provides a unique means of probing the mechanical effects of disease processes and pharmacological treatments on beating cardiomyocytes at the subcellular level, providing new insights relating myocardial structure and function.
Azeloglu
Evren U
EU
Department of Biomedical Engineering at Columbia University, New York, NY, USA. evren.azeloglu@mssm.edu
Costa
Kevin D
KD
D000818:Animals; D001696:Biomechanical Phenomena; D001698:Biomedical Engineering; D002478:Cells, Cultured; D055119:Elastic Modulus; D054459:Elasticity Imaging Techniques / Q000379:methods; D006576:Heterocyclic Compounds, 4 or More Rings / Q000494:pharmacology; D018625:Microscopy, Atomic Force / Q000379:methods; D009200:Myocardial Contraction / Q000187:drug effects / Q000502:physiology; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000502:physiology*; D051381:Rats
D006576:Heterocyclic Compounds, 4 or More Rings; C472645:blebbistatin