Chemo-Mechanical Self-Gating in Polymeric Artificial Cells as Design Tool for Oscillations, Communication, and Autonomous Soft Robots

• Applicant: Professor Dr. Andreas Walther
• Subject Area: Polymer Materials
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 572833231

This project aims to establish chemo-mechanical self-regulation as a design principle for the next generation of synthetic soft matter systems, with a particular focus on oscillatory behavior, communication between artificial cells (ACs), and autonomous soft robotic actuation. The central concept is based on polymeric ACs with self-gating membranes that respond nonlinearly to internal chemical feedback and thereby enable homeostatic control, oscillations, and self-sustained behavior without external intervention. Our key innovation lies in engineering membrane hysteresis in pH-responsive ACs that embed pH-modulating enzymes. By tailoring the composition of weak polyelectrolyte shells with hydrophobic tags, we introduce kinetic delays and nonlinear gating behavior. These features enable autonomous feedback loops that control fuel influx and regulate internal pH in a self-limiting manner. WP1 focuses on systematically understanding how membrane hysteresis influences dynamic regulation in ACs. We establish the key parameters—gate pH, swelling/collapse kinetics, and permeability profiles—using model enzymes such as urease and glucose oxidase, including enzymatic cascades for delayed feedback. In WP2, we exploit these hysteretic ACs to generate sustained chemical oscillations. Two strategies are pursued: (1) nesting ACs inside larger host ACs to introduce hierarchical delayed feedback and (2) spatially coupling ACs via diffusive environments to enable synchronized oscillations in artificial cell consortia. We analyze oscillatory dynamics by microscopy and develop controlled patterning techniques (e.g., µCOP, microfluidic traps) to study synchronization and long-range communication in 2D AC landscapes. WP3 transitions from chemical oscillators to soft robotic function. We embed communicating ACs as “intelligent agents” into pH-responsive hydrogel matrices to create actuators that deform autonomously. Key goals include establishing rhythmic deformation, synchronizing chemo-mechanical behavior, and ultimately achieving gel-based locomotion without external gradients or ratchet surfaces. We aim to demonstrate directional motion via time-asymmetric actuation cycles driven entirely by internal chemical feedback. Altogether, this project introduces a new paradigm of autonomous material behavior by tightly coupling internal reaction networks with mechanical response via self-gating membranes. Our approach moves beyond externally triggered systems toward genuinely self-regulating synthetic matter. The resulting insights will impact the fields of systems chemistry, artificial cells, adaptive soft matter, and next-generation soft robotics.

• DFG Programme: Research Grants