A Study of Frequency Dependency of Cellular Deformation for a Mechanosensing Mechanism of a Cultured Cell under Mechanical Vibration

Abstract

Applying mechanical vibration to cultured cells gives cellular biochemical responses activated so that it can be applied to medical fields such as regenerative medicine. However, the cellular mechanisms of sensing mechanical vibration and transducing into the biochemical responses have not been clarified. One of the previous studies culturing osteoblastic cells under mechanical vibration reported that gene expression levels related to bone formation reached maximum dependent of frequencies like a resonance curve from a mechanical engineering point of view. Considering the analogies between mechanical and biochemical responses of a cell, modes of vibration of a cell can be related to the cellular mechanisms of mechanosensing. In this paper, we experimentally measured displacement of a fluorescently labeled nucleus of living cell under horizontal mechanical vibration of 25-100 Hz, 0.5-2.0 G by using an experimental system consisting of an electromagnetic exciter, a fluorescent microscope, and a high-sensitivity and high-speed camera. To measure the displacement from the images captured under static state and dynamic state where the velocity of vibration was 0, fluorescent microspheres were adhered on the bottom of a cell culture dish as the reference positions. As a result, the displacements of the nucleus were measured but frequency dependencies were not observed in those conditions. This present paper will contribute to elucidating upstream of the mechanisms of mechanosensing from mechanical engineering point of view.