Fluid control

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

• (a) 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 said chamber is configured to be compressed or decompressed to expel gas from or draw gas into the chamber, which in turn causes movement of the liquid sample within said/each microfluidic channel;
• and
• (b) the reader device for use with the microfluidic system comprises:
• a 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 configured to directly or indirectly compress or decompress the gas filled chamber through displacement of the actuator.