Responsive Open Microfluidic Logic for Mechanical Computing.

Logic circuits, a cornerstone of digital computation, have been increasingly adapted to microfluidic systems to enable autonomous, programmable fluidic operations that can also interact with the environment. Unlike traditional microfluidics, which rely on enclosed channels and external pumps, open microfluidics leverage capillary spontaneous flow to manipulate liquids. Integrating logic into these systems facilitates sequential dispensing, mixing, and reaction triggering, without the need for external electronic inputs or pumps. This study leverages elasto-capillary coupling to implement logic in open microfluidic platforms, encoding binary operations through geometric constraints and responsive soft materials. We demonstrate the realization of fundamental gates (AND, OR, NOT, and XOR) and more complex circuits with computational capabilities (half-adder and full-adder). We construct a motorized actuation system that delivers the mechanical input with high reproducibility, supporting applications in diagnostics, microliter reaction handling, and interaction of fluidic systems with the environment. By combining simplicity in operation with the robustness of logic-based control, this approach lays the foundation for next-generation responsive microfluidic systems and mechano-fluidic computing.