Autonomous Integrated Microfluidic Circuits for Chip-Level Flow Control Utilizing Chemofluidic Transistors

In microfluidics, a variety of platforms have emerged facilitating various physical effects for manipulating small volumes. Despite great functional diversity, most technologies are incapable of acting on direct feedback from the process liquid and instead require a sophisticated external control unit off-chip. Here, a microfluidic platform concept is demonstrated utilizing the volume phase transition of polymers via transistor-like components to actively switch between discrete fluid streams. Control is integrated at chip level for the first time, relying on information carried within the process liquid. Control commands are chemical signals such as solvent concentration, pH-value, or even salt. The developed logical modules can be interconnected independently through conclusive signal propagation, supporting an integrated circuit concept and large-scale integration. The approach enables the development of the basic logic gates (AND, OR, NOT) and their negated counterparts, as well as more sophisticated circuits such as an RS flip-flop and a chemofluidic oscillator.