Fluid control

An assay system comprising a self-contained microfluidic system and an associated reader device, wherein:

• the self-contained microfluidic system comprises:
• a sample input port for receiving a liquid sample to be assayed, the sample input port connected to at least one microfluidic channel, wherein each/said microfluidic channel(s) comprises one or more reagents deposited therein for use in conducting an assay and a detection zone for use in detecting any analyte which may be present in a sample or analyte reaction product;
• and
• each/said microfluidic channel(s) is in fluid communication with a compressible, gas-filled chamber downstream from each/said detection zone,
• wherein the microfluidic system is formed from three layers, which are sandwiched together in order to define each/said microfluidic channel(s) and said gas filled chamber, and wherein compressing or decompressing said chamber causes gas to be expelled from or drawn into the chamber, which in turn causes movement of the liquid sample within said/each microfluidic channel;
• and
• a reader device for use with the microfluidic system, the reader device comprising:
• force control means for controlling compression or decompression of the gas filled chamber of the microfluidic system;
• and detection means for enabling detection of a desired analyte within a liquid sample introduced into the microfluidic cartridge, or analyte reaction product thereof;
• wherein the force control means comprises a piezoelectric bending actuator which is designed to directly or indirectly compress or decompress the gas filled chamber through displacement of the actuator.

A method of conducting an assay on a liquid sample, the method comprising:

• a) compressing a/said gas filled chamber(s) of the self-contained microfluidic system according to claim 1, so as to expel gas from said/each gas filled chamber(s);
• b) introducing a liquid sample to the self-contained microfluidic system and allowing the sample to be drawn into said/each microfluidic channel(s) by capillary action, and/or partially decompressing said/each gas filled chamber(s) such that gas is drawn into said/each chamber(s) thereby causing the liquid sample to be drawn into said/each microfluidic channel(s);
• c) allowing one or more reagent(s) to react with any analyte present in the liquid sample;
• d) optionally partially further partially decompressing said/each gas filled chamber(s) of the microfluidic system, such that the liquid sample is drawn further along said/each microfluidic channel(s) towards said/each gas filled chamber(s) and optionally contacting the liquid sample with an analyte binding agent and/or one or more further reagent(s);
• e) optionally capturing any analyte or analyte reaction product and compressing said/each gas filled chamber(s), such that gas expelled from said/each chamber(s) causes the liquid sample and uncaptured material to be pushed away from any captured analyte or analyte reaction product;
• and
• f) detecting any analyte or analyte reaction product, or captured analyte or analyte reaction product.