Viscoelastic behaviour of human mesenchymal stem cells

Background: In this study, we have investigated the viscoelastic behaviour of individual human adult bone marrow-derived mesenchymal stem cells (hMSCs) and the role of F-actin filaments in maintaining these properties, using micropipette aspiration technique together with a standard linear viscoelastic solid model. Results: Under a room temperature of 20°C, the instantaneous and equilibrium Young's modulus, E0 and E∞, were found to be 886 ± 289 Pa and 372 ± 125 Pa, respectively, while the apparent viscosity, μ, was 2710 ± 1630 Pa·s. hMSCs treated with cytochalasin D up to 20 μM at 20°C registered significant drop of up to 84% in stiffness and increase of up to 255% in viscosity. At the physiological temperature of 37°C, E0 and E∞ have decreased by 42-66% whereas μ has increased by 95%, compared to the control. Majority of the hMSCs behave as viscoelastic solid with a rapid initial increase in aspiration length and it gradually levels out with time. Three other types of non-typical viscoelastic behavior of hMSCs were also seen. Conclusion: hMSCs behave as viscoelastic solid. Its viscoelstic behaviour are dependent on the structural integrity of the F-actin filaments and temperature.