Single-layer microfluidic current source via optofluidic lithography

This work marks the first use of in-situ photopolymerization to create single-layer microfluidic devices which serve as ultra-low Reynolds Number (Re) current sources to regulate fluid flow rate independent of operating pressures. Autonomous fluidic components are an emerging aspect of micro/nanofluidic circuits and applications; however, many existing fluidic applications require specific pressure and/or flow rate conditions to perform optimally, and many require complex and expensive fabrication procedures. Here we introduce single-layer microfluidic system which utilize a spring and piston system - fabricated in situ via optofluidic lithography - to passively constrain fluid flow rate to a value independent of operating pressure. Experimental results revealed controlled flow rates of 29.2 ± 0.8 μl/min (from P = 50-100 mbar) and a maximum small-signal resistivity of 141.1 mbar-min/μl, which represents the highest performance for a low-pressure microfluidic current source.