Sustained, reversible and adaptive non-equilibrium steady states of a dissipative DNA-based system

Sustaining dissipative artificial systems in non-equilibrium steady states (NESS) through the continuous supply of a chemical fuel under open thermodynamic conditions remains largely unexplored. Here, we demonstrate unprecedented NESS of a dissipative DNA strand-displacement reaction achieved by the continuous supply of an RNA fuel to a stirred semi-batch reactor. This was enabled by a custom automated setup that allows for tuneable fuel infusion rates and in situ fluorescence monitoring. The system can be maintained in NESS for extended periods and shows high reversibility, cycling between the equilibrium state and different NESS simply by halting and resuming the infusion. The system can also dynamically adapt to subtle variations in fuel supply (on the fly) by approaching different steady-state levels, mimicking nature’s ability to establish distinct NESS in response to changes in environmental conditions. By fitting the experimental data to a kinetic model of the reaction network, we demonstrate that the steady states obtained are indeed characterised by non-equilibrium concentrations of the species involved, thereby representing ‘genuine’ NESS.