Figure 1. . Working principles of pneumatic micropumps.

(A) The peristaltic sequence of three microvalves in an S-shape pneumatic micropump to pump the fluid forward. (i) Schematic representation of the sequence; (ii) a top view of the pumping motion corresponding to (i). (B) Side view of a passive pump composed of two reservoirs and bridge. (i) Schematic representation of the pump; (ii) the critical parameters involved in the working mechanism of this pump.

(A) Reproduced with permission from [39] © Springer (2007).

(B) Reproduced with permission from [41] © The Royal Society of Chemistry (2002).