Programmable positive and negative chemotaxis of polymeric vesicles driven by degradation

Abstract Chemotaxis enables organisms and cells to move either toward or away from specific cues. Artificial protocells capable of integrating both positive and negative chemotaxis into one system are still very rare outside the biological realm and often require elaborately designed catalytic reactions with complex adaptation processes. Furthermore, the chemotactic mechanism of artificial systems is not yet fully investigated and understood especially at the molecular level. Here, we introduce degradation as a new propulsion mechanism for chemotactic polymeric vesicles without any external modification of the system. The vesicles can be programmed to exhibit either positive or negative chemotaxis by sensing the degrading catalyst as the attractant or the degradation products as the repellents. We systematically examined the possible mechanisms of the chemotaxis by a flow-chart toolbox approach and highlight the degradation-driven mechanism involved at the molecular level. The programmable chemotaxis driven by degradation represents a conceptually novel way to guide the design of artificial chemotactic protocells and opens a new route for biodegradable systems in fields such as the active delivery or artificial communication under out-of-equilibrium conditions.