Control systems for synthetic biology and a case-study in cell fate reprogramming

TL;DR

This paper reviews control systems engineering applications in synthetic biology, focusing on controlling regulatory factors for cell reprogramming, emphasizing robustness, biomolecular implementation constraints, and future challenges.

Contribution

It introduces biomolecular control architectures for cell fate reprogramming and discusses their design constraints and practical implementation challenges.

Findings

Control strategies can reprogram cell fate by regulating key factors.

Robust control architectures improve accuracy despite environmental perturbations.

Biomolecular implementation constraints limit feasible control laws.

Abstract

This paper gives an overview of the use of control systems engineering in synthetic biology, motivated by applications such as cell therapy and cell fate reprogramming for regenerative medicine. A ubiquitous problem in these and other applications is the ability to control the concentration of specific regulatory factors in the cell accurately despite environmental uncertainty and perturbations. The paper describes the origin of these perturbations and how they affect the dynamics of the biomolecular ``plant'' to be controlled. A variety of biomolecular control implementations are then introduced to achieve robustness of the plant's output to perturbations and are grouped into feedback and feedforward control architectures. Although sophisticated control laws can be implemented in a computer today, they cannot be necessarily implemented inside the cell via biomolecular processes. This fact constraints the set of feasible control laws to those realizable through biomolecular processes that can be engineered with synthetic biology. After reviewing biomolecular feedback and feedforward control implementations, mostly focusing on the author's own work, the paper illustrates the application of such control strategies to cell fate reprogramming. Within this context, a master regulatory factor needs to be controlled at a specific level inside the cell in order to reprogram skin cells to pluripotent stem cells. The article closes by highlighting on-going challenges and directions of future research for biomolecular control design.