Patent ID: 7238324

Claim:
A microfluidic device comprising: a sensing substrate bound to a channel substrate, the sensing substrate including a sensing electrode, an electrode interconnect and an electrode pad, the channel substrate including a first fluid inlet port at a side of the channel substrate, a first fluid addition chamber around the first fluid inlet port, a sample reaction barrier connecting a sensing chamber with the first fluid addition chamber, and a second fluid inlet port at the other side of the channel substrate, a second fluid addition chamber around the second fluid inlet port, a channel connecting the second fluid addition chamber and the sensing chamber, and a used reagent reservoir connected to the sensing chamber; a first fluid comprising a sample for loading into the sensing chamber via the first fluid inlet port and a second fluid comprising a buffer solution for loading into the sensing chamber via the second fluid inlet port; an external pump for forcing fluid flow from the second fluid inlet port to the sensing chamber; and wherein the channel substrate is dimensioned such that a sample loaded via the first fluid inlet port flows into the sensing chamber through the first fluid addition chamber solely by capillary force, the sensing chamber having outlets which are larger than an inlet of the sensing chamber such that the capillary force diminishes at the sensing chamber outlets, and a buffer solution loaded via the second fluid inlet port flows by the action of the external pump through the channel and the sensing chamber, for washing reacted products, and is reserved in the used reagent reservoir.