On a Zero-Retroactivity Subtraction Module for Embedded Molecular Feedback Controllers

The control of biochemical processes is a major goal in many fields, encompassing metabolic engineering and synthetic biology. Current approaches are based on ad-hoc designs, whereas a general and modular framework would be highly desirable, in order to exploit the well-assessed methods of control theory. A well-known problem when dealing with complex biosystems is represented by the retroactivity effect, which can significantly modify the dynamics of interconnected subsystems, with respect to the behaviour they exhibit when disconnected from each other. In the present work an implementation of a zero retroactivity Chemical Reaction Network Subtractor (CRNS) is proposed and its effectiveness is investigated through singular perturbations analysis. The proposed CRNS represents a first step towards the modular designing of embedded feedback biochemical controllers.