High-radix microfluidic multiplexers using pressure valves of different thresholds

Abstract

We propose high-radix microfluidic multiplexers that effectively address a large number of flow channels with a few control lines having pressure valves of different thresholds. Previous binary multiplexers address only two flow channels by controlling identical threshold pressure valves in two control lines; that is, they address $2^{n/2}$ flow channels by using n control lines. However, the proposed high radix multiplexer, ternary or quaternary multiplexer, address three or four flow channels by controlling two or three kinds of valves in two control lines, respectively. Thus, these multiplexers address $3^{n/2}$ and $4^{n/2}$ flow channels, which are results by increasing the radix from binary to quaternary. In experiment, we determined the static/dynamic operating conditions of the pressure valves having different thresholds in the ternary and quaternary multiplexers. Under these conditions, the prototypes such as 3×3 well array, 4×4 well array and digital dilution chip are successfully operated. In well array test, the ternary and quaternary multiplexers selectively fill out 3×3 and 4×4 well array, respectively. In the dilution chip, the ternary multiplexer controls nine valves which dilute sample within 16.7% error and react samples within 17.7% error. Thus, the present high-radix multiplexers reduces the number of control lines for multiple flow channel and valve addressing, achieving effective flow channels control required for simple and compact microfluidic systems.