Fig. 1.

(A) Key layout features of a two-layer device. The black layer is the flow layer (containing trapping channels) where particle/cell trapping is accomplished. The red layer is the control layer (containing valve channels). The crossed area between the two layers forms a very thin PDMS membrane, which controls the opening or closing the flow channel, depending on the applied pressure in the control channel. (B) Schematic diagram showing the trapping channel in the flow layer. Inset shows a close-up view of Path 1, which contains five regions (notated as i–v respectively). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)