The development and function of living tissues depends largely on interactions between cells that can vary in both time and space; however, temporal control of cell–cell interaction is experimentally challenging. By using a micromachined silicon substrate with moving parts, we demonstrate the dynamic regulation of cell-cell interactions via direct manipulation of adherent cells with micrometer-scale precision. As a case study, we demonstrate the utility of this tool in deconstructing the dynamics of intercellular communication between hepatocytes and supportive stromal cells in co-culture. Our findings indicate that the maintenance of the hepatocellular phenotype by stroma requires direct contact for a limited time (~hours) followed by a sustained soluble signal that has an effective range of <400 um. This platform enables investigation of dynamic cell–cell interaction in a multitude of applications.