Microfluidic chip, kit, and system for displacing independent reaction volumes of an emulsion

A centrifugal microfluidic chip for mounting to a centrifuge for rotation about an axis, the chip comprising a network of chambers and interconnecting channels including:

• a treatment chamber (tc) having:
• a volume (vtc) of 10-800 μL;
• and a mean length (ltc), mean width (wtc) and mean depth (dtc), with dtc<ltc, and dtc<wtc;
• a first path adapted to deliver a sample to the tc, the first path comprising a nozzle having a hydrodynamic radius rn of 2-120 μm, adapted to deliver the sample to the tc discretized, as emulsion-divided independent reaction volumes (IRVs) if the nozzle is filled with a suitable medium;
• a presentation chamber (pc) coupled to the tc by an opening through which the IRVs can be selectively displaced from the tc to the pc;
• a window transparent for inspecting the pc, provided through the chip at least across a length and width of the pc;
• and
• a retraction chamber (rc) coupled by a second path to the pc,
• wherein:
• dtc is between 5×rn and 2 mm;
• the pc has a depth (dpc) between 1.2×rn to 7×rn;
• dtc>2 dpc;
• and a flow path through the opening has a minimum hydrodynamic radius greater than 8×rn.