Abstract: The invention relates to methods and devices for detecting a cell-cell interaction between a first living cell and a second living cell. The method comprises (a) providing a flow passage defined at least in part by a substrate having a first living cell, or tissue section containing living cells, immobilized on a surface thereof, (b) introducing a second living cell by controlled delivery of a carrier fluid containing the second living cell in contiguous laminar flow through the flow passage, thereby effecting contact or proximity between the first living cell and the second living cell, and (c) detecting a cell-cell interaction, if present, as a result of the contact or proximity between the first living cell and the second living cell. Devices for carrying out the method and for providing a cell-cell interaction are provided as well.