Research article

Viscoelastic behaviour of human mesenchymal stem cells

Samuel CW Tan^{* 1} , Wen X Pan^{* 2} , Gang Ma² , Ning Cai¹ , Kam W Leong^3,4 and Kin Liao¹

¹Division of Bioengineering, School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637457, Singapore

²Biomedical Engineering Research Center, School of Electrical & Electronic Engineering, Nanyang Technological University, Singapore 637553, Singapore

³Duke-National University of Singapore Graduate Medical School, Singapore 169547, Singapore

⁴Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA

author email corresponding author email* Contributed equally

BMC Cell Biology 2008, 9:40doi:10.1186/1471-2121-9-40

Published:	22 July 2008

Abstract

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.