Effect of Varying Urethane Thickness on Valves

On-board pneumatic valves produced with laminate fabrication processes provide a cost effective way to perform metering mixing and gating of fluid movement in Lab on a chip devices. These valves can be used in multiplexed molecularor immunoassays where successive reagent additions and/or washes are needed. The laminate valve assembly, produced in a batch fabrication process, is combined with an injection molded component that contains the reagent reservoirs, along with either an optical or electroactive sensor for detection, enabling complete sample to answer performance. To meet the cost and performance requirements for single use devices, the valves must be easy to produce in volume with performance characteristics that are tolerant to a range of pressures, channel geometries and fluid processing requirements while being ammenable to volume production. This paper investigates the geometry required to match the functional performance of our pneumatically actuated diaphragm valves using a .001” urethane vs .002” and .004” thick urethane. Also of interest is the viability of the spike and hold method of closing valves using the standard valve geometry.