Abstract: Described herein is a system and method for determining the presence and/or amount of a target in a sample. In some embodiments, a microfluidic device, such as a strip having a microfluidic network thereon, is inserted into an instrument to perform an assay therein. The strip may be configured to receive the sample from a porous member via capillary action, with minimal or no compression of the porous member. The instrument may include a gas bladder actuation assembly, actuated by an eccentric cam, to compress and decompress a gas bladder on the microfluidic device, thereby enabling fluid movement thereon. The instrument may further comprise a magnet disposed in a fixed location, so as to capture any complexes formed between the target and magnetic particles disposed within the microfluidic device. The magnet may be aligned with an optical detection assembly configured to detect the target captured with the magnetic particles.

Abstract: A diagnostic system for determining the presence of a target in a sample liquid that includes a diagnostic reader and a microfluidic strip having a microfluidic channel network therein. An actuator within the reader modifies the pressure of a gas in gaseous communication with a liquid-gas interface of a sample liquid within the microfluidic channel network to move and/or mix the sample liquid. The pressure modifications may be continuous and/or oscillatory.