| abstract |
Flow-through assay reaction chamber ( 6 ) of cassette has back and forth liquid mixing in narrow gap (G) over array of capture agent (S), with net flow advance to waste confinement ( 19 ), produced by reversible pumps ( 3 or 12 ), operable with rolling diaphragm action with at least limited elastic recovery that advance sample or buffer liquids through conditioning paths ( 4 A, 8, 8′, 9, 14, 15, 15′ ) before reaching the reaction chamber ( 6 ). A single pump produces accurate flow control, liquid conditioning, e.g., liquefying dry reagent from internal surfaces of flow-dividing material ( 14 a, 15 A, 15 A′, e.g. open cell foam or frit), heating ( 4 A), and air bubble removal ( 8, 8′, 9 ), as well as replenishment of reagent while accomplishing mixing within the flow-through reaction chamber ( 6 ). Lower viscosity buffer liquid is arranged to propel higher viscosity reagent, the flow-dividing storage material preserving reagent concentration. A blister pack ( 11 ) acts as a reversible pump ( 12 ) in producing accurate forward and backward flows with the net flow advance. Cascaded bubble traps ( 8, 9 ) on the cassette render the system tolerant of minor pumping error during cassette priming. |