A noninvasive approach to determine viscoelastic properties of an individual adherent cell under fluid flow.

Mechanical properties of cells play an important role in their interaction with the extracellular matrix as well as the mechanotransduction process. Several in vitro techniques have been developed to determine the mechanical properties of cells, but none of them can measure the viscoelastic properties of an individual adherent cell in fluid flow non-invasively. In this study, techniques of fluid-structure interaction (FSI) finite element method and quasi-3-dimensional (quasi-3D) cell microscopy were innovatively applied to the frequently used flow chamber experiment, where an adherent cell was subjected to fluid flow. A new non-invasive approach, with cells at close to physiological conditions, was established to determine the viscoelastic properties of individual cells. The results showed an instantaneous modulus of osteocytes of 0.49 ± 0.11 kPa, an equilibrium modulus of 0.31 ± 0.044 kPa, and an apparent viscosity coefficient of 4.07 ± 1.23 kPas. This new quantitative approach not only provides an excellent means to measure cell mechanical properties, but also may help to elucidate the mechanotransduction mechanisms for a variety of cells under fluid flow stimulation.