Abstract: Cell carrier structures using dynamic flow of cell bearing, washing, or nourishing fluid, from an input reservoir region to an output reservoir region. A common feature of the several structures by which this can be achieved is the presence of channels generally having low height or other cross section, such that the cell bearing fluid readily traverses these channels by capillary action. Optional pumping assistance can also be provided. The capture wells or traps are disposed generally along the length of these channels such that the cells have multiple chances of being captured in a trap or well. The traps or wells are structured such that only a single cell can be trapped in each well or trap, and the disposition of the wells or traps as appendages to the fluid flow channels facilitates the washing or nourishing of the cells while their proliferation or development is being observed.