A microfluidic cartridge for placement onto a parallel pneumatic interface plate of a pneumatic instrument is provided. The cartridge includes a three dimensional fluid channel, in which a fluid is to be transported, a flexible membrane that spans a plane and is part of an outer surface of the cartridge. The three dimensional fluid channel is spatially defined in three dimensions by internal walls of the cartridge and by the flexible membrane. The flexible membrane is in a ground state, when no pressure or vacuum is applied to the flexible membrane. However, the flexible membrane is pneumatically deflectable from the ground state perpendicular to the plane of the flexible membrane in two directions when the cartridge is placed onto the parallel pneumatic interface plate.