title: A simple check valve for microfluidic point of care diagnostics.
abstract: Check valves are often essential components in microfluidic devices, enabling automated sample processing for diagnostics at the point of care. However, there is an unmet need for a check valve design that is compatible with rigid thermoplastic devices during all stages of development-from initial prototyping with a laser cutter to final production with injection molding. Here, we present simple designs for a passive, normally closed check valve that is manufactured from commonly available materials with a CO2laser and readily integrated into prototype and production thermoplastic devices. The check valve consists of a thermoplastic planar spring and a soft elastomeric pad that act together to seal against fluid backflow. The valve's cracking pressure can be tuned by modifying the spring's planar geometry and thickness. Seal integrity is improved with the addition of a raised annular boss beneath the elastomeric pad. To demonstrate the valve's usefulness, we employ these valves to create a finger-operated on-chip reagent reservoir and a finger-actuated pneumatic pump. We also apply this check valve to passively seal a device to enable portable detection of RNA from West Nile virus in a laser-cut device.
authors.affiliation: Sandia National Laboratories, 7011 East Ave., Livermore, CA 94550, USA. csball@sandia.gov rmeaghe@sandia.gov.
authors.forename: C S
authors.identifier: 0000-0001-7508-5449
authors.initials: CS
authors.lastname: Ball
authors.affiliation: Sandia National Laboratories, 7011 East Ave., Livermore, CA 94550, USA. csball@sandia.gov rmeaghe@sandia.gov.
authors.forename: R F
authors.initials: RF
authors.lastname: Renzi
authors.affiliation: Sandia National Laboratories, 7011 East Ave., Livermore, CA 94550, USA. csball@sandia.gov rmeaghe@sandia.gov.
authors.forename: A
authors.initials: A
authors.lastname: Priye
authors.affiliation: Sandia National Laboratories, 7011 East Ave., Livermore, CA 94550, USA. csball@sandia.gov rmeaghe@sandia.gov.
authors.forename: R J
authors.initials: RJ
authors.lastname: Meagher
mesh_terms: D004867:Equipment Design; D056656:Lab-On-A-Chip Devices; D019095:Point-of-Care Systems; D011312:Pressure; D012367:RNA, Viral / Q000032:analysis; D014902:West Nile virus / Q000235:genetics / Q000302:isolation & purification
chemical_list: D012367:RNA, Viral