<B>Abstract:</B>

We have developed a tool, which we call Single-Cell-Pico-Force-Microscopy, capable of measuring cellular forces from individual adherent cells with the high resolution necessary to track macro-molecular force dynamics in living cells. We present our initial results from studies of contracting and relaxing lamellipodia of cells perturbed with Cytochalasin D. We propose a mechanism and quantitative model explaining cellular force disruption by Cytochalasin D. This work illustrates the immense potential of NEMS based tools for significantly enhanced resolution of cell biology at the single cell level.