Microfluidic Bubble Logic

We present an all-fluidic universal logic family operating at low Reynolds number in two-phase flow microfluidics. A bubble traveling in a channel represents a bit, providing us with the capability to simultaneously transport materials and perform logical process control operations. Nonlinearities are introduced in the system via hydrodynamic bubble-to-bubble interactions in static channel geometries. We demonstrate bubble logic AND/OR/NOT gates, a toggle flip-flop, a ring oscillator and an elctro-bubble modulator. These show the nonlinearity, gain, bistability, cascadability, feedback and programmability required for scalable universal computation. With increasing complexity in large scale microfluidic processors, bubble logic provides an on-chip process control mechanism integrating chemistry and computation.