The mechanism of the particle interactions is still inconclusive, even though many researchers have tried to figure out the particle-particle interactions under the influence of electric field. In this paper we report an experimental investigation of electrostatic attraction and repulsion of endothelial cells in an image-driven light induced dielectrophoresis (DEP) apparatus. The optoelectronic tweezers (OET) device consists of a planar structure having one or more portions which are photoconductive to convert incoming light to a change in the electric field pattern. When the cells are manipulated in OET chip at a frequency near the threshold of electrolysis, cells exhibits numerous interesting phenomena such as spinning, collision, rotation and pearl chain effect in three-dimensional (3D) space. All of these cell behaviors at such critical frequencies on this OET chip are reported.