Sieve valves, microfluidic circuits, microfluidic devices, kits, and methods for isolating an analyte

A microfluidic circuit for capturing and isolating an analyte or sample component said circuit comprising:

• an input valve;
• one or more holding chambers in fluid communication with the input valve;
• a mixing circuit comprising a plurality of chambers in fluid communication with the one or more holding chambers, wherein the one or more holding chambers and/or the mixing circuit comprises a capture substrate for capturing and isolating the analyte or component;
• one or more sieve valves positioned between the holding chamber and the mixing circuit and positioned in at least partial fluid communication with one or more of the plurality of chambers of the mixing circuit, and
• one or more sieve valves positioned in at least partial fluid communication with one or more of the plurality of the chambers of the mixing circuit,
• wherein each of the one or more sieve valves includes:
• a substrate defining a channel;
• a flexible membrane adapted and configured for deployment at an intersection with the channel;
• wherein
• one or more protrusions extend into the channel from the substrate and are situated opposite the flexible membrane, the one or more protrusions defining a plurality of recesses extending beyond the intersection between the channel and the flexible membrane;
• and
• an output valve.