Fluid induced mechanical environment of cells during high-frequency oscillations in-vitro

Bone cells can perceive high-frequency oscillations as an anabolic signal. The oscillatory motions will generate forces not only through accelerations but also through fluid-cell interactions within the bone structure. Here, we describe a combined computational and experimental method to quantify the mechanical environment that cells are exposed to during high-frequency mechanical oscillations in-vitro. Finite element (FE) modeling determined the velocity profile of a viscous fluid in a rigid container oscillating horizontally at 60 Hz with 1g peak accelerations. Predicted peak fluid shear stresses approached 0.1Pa. When compared to FE, speckle interferometry revealed a similar fluid behavior over one cycle. The identification of fluid shear as a force concomitant to accelerations during high frequency oscillations in-vitro emphasizes that there are multiple potential mechanisms by which cells may sense these low-magnitude mechanical signals.