Gas-Fueled Active Coacervate Droplets With Gas-Programmable Temporal Dynamics

Synthetic droplets mimicking membraneless biomolecular condensates via liquid-liquid phase separation have emerged as ideal protocell models. To impart dynamic adaptation closer to those of living matter, recent challenges have shifted toward engineering active droplets that couple with fuel-driven reaction cycles to temporally control the dynamics of droplets far from equilibrium. Here we report a transient coacervate droplet system powered by a unique form of fuel-gas molecules. Using complementary frustrated Lewis pair polymers (FLPPs) as precursors, CO₂ gas can cross-link them through dynamic gas-bridged bonds and induce demixing to access transient coacervation. In turn, the bound FLPPs within the assembly unlock their catalytic activity toward CO₂, which results in the depletion of the gas via CO₂-involved carboxylation reactions-an intrinsic catalytic role that helps dissociate the formed coacervates. Varying gas parameters or tailoring substrate structures enable temporal regulation of the coacervation cycle in period and amplitude across a wide window. More importantly, these droplets can manifest complex temporal behaviors with pulse-type dynamics when leveraging dual gas fuels (CO₂ and SO₂) to program the process. This kinetic complexity stems from competitive gas binding with FLPPs and tunable catalysis. This study will inspire a new avenue for using gas fuels to drive dissipative coacervation for life-like functions.