Figure 1.

Schematic illustration of the principle used to detect the secretion of protein from single PC cells with or without drug stimulation. (a) An array of microwells with a pore in the bottom. (b) A single cell suspension is added on top of the microwell array and a negative pressure is applied. (c) Images of the cells in microwells are acquired. (d) To capture the secreted PSA, a membrane is mounted against the bottom of the microwell array. (e) During incubation, cell-secreted PSA is captured on the membrane. (f,g) Microwells and the membrane are disconnected. (h) The membrane is fluorescently labeled to detect PSA and (i) microwells are supplemented with a drug and connected to a second membrane. (j,k) After incubation (24 h), the membrane and microwells are separated. (l) The membrane is fluorescently labeled to detect PSA and (m) microwells are supplemented with a drug and connected to a third membrane. (n,o) Finally, after another incubation period (24 h), the membrane is separated from the microwells and (p) stained to visualize the membrane that captured PSA from PC cells.