In practical applications of dynamic DNA nanotechnology, a biomolecular controller is required for maintaining the operation of the molecular actuator at a desired condition based on the information from molecular sensors. By making use of the DNA strand displacement mechanism as a “programming language” in the controller design, a biomolecular PI controller has been proposed. However, this PI control system has been verified only at the simulation level, and a theoretical regulation analysis is still required. Accordingly, in this study, we perform a rigorous regulation analysis of the biomolecular PI control system. Specifically, we theoretically prove that the output signal approaches the target level at a quasi-steady state. To this end, we apply the concept of finite-time regulation property to the biomolecular PI control system
