Analysis of pairwise cell interactions using an integrated dielectrophoretic-microfluidic system.

Blood vessel formation, during either normal vascular reconstruction or pathogenic tumour formation, relies upon highly organized cell-cell interactions. Isolating the function of any particular component of this cell-cell communication is often difficult, given the vast complexity of communication networks in multicellular systems. One way to address this problem is to analyse cell-cell communication on the most elementary scale--cell pairs. Here, we describe an integrated dielectrophoretic (DEP)-microfluidic device allowing for such analysis. Single cancer and endothelial cells (ECs) and cell pairs were patterned using DEP force and cultured within a minimally stressful microfluidic channel network. Controlling both the initial cell positions and extracellular environment, we investigated cell motility in homo- and heterotypic cell pairs under diverse conditions. We found that secreted collagen IV and soluble vascular endothelial growth factor have considerable guidance effect on ECs at the level of two interacting cells. Cell interaction rules extracted from the experiments of cell pairs were used to mathematically predict branching patterns characteristic of developing multicellular blood vessels. This integrative analysis method can be extended to other systems involving complex multicellular interactions.