Design rules and operational optimization for rapid, contamination-free microfluidic transfer using monolithic membrane valves

Networks of monolithic membrane microvalves integrated into microdevices enable complete automation of liquid-based chemical analyses necessary for fully automated applications, such as spaceflight. Although individual pumping devices and operational routines have been characterized, to date there has been no rigorous evaluation of microvalve layout and its effect on fluidic transfer. Here, we evaluate two microdevices at opposite extremes of fluidic resistance and evaluate three pumping routines on each device. Delay times between operational steps are optimized for fastest fluidic transfer. A 3-valve double-chamber routine enables fastest pumping rates on both devices. On low fluidic resistance devices, a 2-valve (bivalve) pumping routine enables faster fluidic transfer than a 3-valve single-chamber pumping routine. Additionally, low fluidic resistance devices enable significantly faster fluidic transfer (4–6 fold) than their higher resistance counterparts. Back-contamination is qualitatively characterized for the optimized routines; higher fluidic resistance between the pumping architecture and the fluidic output reservoir is the most essential feature for preventing back-contamination. We use these results to suggest design rules to guide future pumping architectures to enable the rapid, contamination-free fluidic transfer that will be necessary in spaceflight applications.