FIGURE 1 

The TC design was optimized to allow for long-term growth of cells in a monolayer. (A) Three separate ports for cell loading (C), media supply (M), and waste (W) minimize potential clogging of media supply lines. With this layout, we are able to generate optimal fluid flow both for the loading of cells into the trapping region and for the delivery of nutrients over many generations. Strong flow toward the trapping region provides the momentum necessary to carry cells into the region against high resistance. Cells that do not enter the trapping region are forced into the waste port by strong flow from the media port. Once cells are loaded, flow is reversed to run from the media port to both the waste and cell ports. Running temperature-regulated water through thermal lines T1 and T2 maintains the device at an optimal temperature. (B) A zoomed-in view of the diode loop. The height of the trapping region (dark gray) is customized based on species. The flow channels (black) are 2-3 times higher than the trapping region. An open trapping region (black/gray interface) allows for peripheral cells to be pushed from the observation region as the colony grows. (C) Shallow trapping regions confine cells to a monolayer. Cells residing at the trapping region entrance highlight the benefit of a height-constrained growth environment. Scale bar, 20 m. (D) The 4-m-high yeast TC full of cells after 24 h of growth. Scale bar, 20 m.