Cyclic transformation of stable/metastable nucleic acid structures enables dynamic monitoring of ATP in living cells.

The maintenance of living systems relies on complex signaling networks involving nucleic acids, proteins and small molecules. However, conventional analytical approaches are often limited to endpoint measurements or analyses performed outside native biological environments, restricting their ability to monitor biomolecular dynamics in space and time. Here we report an artificial riboswitch-based dynamic sensing system that enables programmable nucleic acid regulation through metastable equilibrium fluctuations and steady-state conformational transitions. Through specific molecular recognition and environmental stimulation, this system enables real-time monitoring of small-molecule distributions within complex intracellular environments. Using ATP as a representative target, the platform exhibits dynamic fluorescence responses with mitochondria-associated localization and temporal fluctuation patterns in living cells. This artificial riboswitch strategy provides a versatile platform for programmable nucleic acid dynamic sensing and offers a potential approach for investigating the spatiotemporal behaviors of biomolecules in living systems.