Computer Aided Design of a Microscale Digitally Controlled Hydraulic Resistor

Microscale mechanical networks are prevalent in lab-on-A-chip systems, which are rapidly expanding into biological, chemical, and physical research. In these systems, nano-liter volumes of fluids are manipulated and a precise control of flow in individual segments within a complex network is often desirable. One paradigm for such control suggests adjusting the hydraulic resistance of each segment, relying on the fact that like in electrical circuits, fluid flow is depended upon the relation between the potential drop (pressure difference) and the resistance of the transmitting conductor. Current solutions for the control of hydraulic resistance rely on intricate fabrication processes, are often characterized by a high-biased error and can generally produce a limited range of resistance. Here, a computer-Aided design of a six-bit digitally controlled adjustable hydraulic resistor, which features five linear ranges of resistance and a small footprint is presented. This design can be rapidly embedded within a microfluidic network for real time control of fluid flow.