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Abstract

It is well known that many cells adherent on a cyclically stretched substrate reorient nearly perpendicular to the applied stretching direction. Such periodic mechanical signals are characterized by the stretching amplitude and frequency ad many studies focus on the influence of the amplitude on the orientation behavior. However, little is know about the temporal characteristic and dynamics of this cellular response. Consequently, we developed an experimental stretch system for live cell imaging. Using this setup, we observed the dynamic reorientation of different human fibroblast types over a frequency range 0.01–10 s−1 and a constant stretching amplitude of 8%. We demonstrate an increasing mean cell orientation with an exponentially time characteristics. The characteristic time τ for the reorientation is frequency-dependent and is in a range from 1 to 5 h. This characteristic time is a function of frequency and follows a power law for frequencies below 1s−1,τ decreases with a power law as the frequency increases. For frequencies above 1s−1,τ is nearly constant and the kinetics of cell reorientation is in saturation. In addition, a threshold frequency is found below which no significant cell reorientation occurs. Our results are consistent for the two different human fibroblast types and indicate a saturation of molecular mechanisms of mechanotransduction or response machinery for subconfluent cells within the frequency regime under investigation.