OPTICAL MEASUREMENT OF THE VISCOELASTIC AND BIOCHEMICAL RESPONSES OF LIVING CELLS TO MECHANICAL PERTURBATION

We have developed an optical method for real-time monitoring of cellul ar motion in a natural environment with nanometer resolution. From the motion driven by small optical forces, we measured dynamic viscoelast ic responses of living cells in the linear reversible region. Cytoplas mic gel-to-sol transition that was due to the disruption of the actin- filament framework was detected, and a linear release of Ca2+ from int racellular storage that was related to submicrometer cell deformation was observed. The method was shown to be a powerful tool for studying the natural response of cells to mechanical perturbation. (C) 1998 Opt ical Society of America.