Biocatalytic Feedback‐Driven Temporal Programming of Self‐Regulating Peptide Hydrogels

Abstract

Switchable self-assemblies respond to external stimuli with a transition between near-equilibrium states. Although being a key to present-day advanced materials, these systems respond rather passively, and do not display autonomous dynamics. For autonomous behavior, approaches must be found to orchestrate the time domain of self-assemblies, which would lead to new generations of dynamic and self-regulating materials. Herein, we demonstrate catalytic control of the time domain of pH-responsive peptide hydrogelators in a closed system. We program transient acidic pH states by combining a fast acidic activator with the slow, enzymatic, feedback-driven generation of a base (dormant deactivator). This transient state can be programmed over orders of magnitude in time. It is coupled to dipeptides to create autonomously self-regulating, dynamic gels with programmed lifetimes, which are used for fluidic guidance, burst release, and self-erasing rapid prototyping.

Dynamic Environments as a Tool to Preserve Desired Output in a Chemical Reaction Network

“…[1] Examples of networks giving temporal, or spatiotemporal, control over the concentrations of the molecules in the system include the generation of wave fronts, [2] pattern formation with as o-calledg o-fetch model, [3] oscillations, [4][5][6][7][8] supramolecular oscillators [9] synchronisation and pattern formation with multiple oscillators through diffusional spatiotemporal coupling, [10] adaptive response networks, [11] systemss howing homeostasis, [12] self-replicating systems that can diversify into differents pecies, [13] self-replicators that can transiently form micelles, [14,15] temporally controlled material properties [16][17][18] and transientv esicle, [19] droplet, [20] fibril and gel formation. [1] Examples of networks giving temporal, or spatiotemporal, control over the concentrations of the molecules in the system include the generation of wave fronts, [2] pattern formation with as o-calledg o-fetch model, [3] oscillations, [4][5][6][7][8] supramolecular oscillators [9] synchronisation and pattern formation with multiple oscillators through diffusional spatiotemporal coupling, [10] adaptive response networks, [11] systemss howing homeostasis, [12] self-replicating systems that can diversify into differents pecies, [13] self-replicators that can transiently form micelles, [14,15] temporally controlled material properties [16][17][18] and transi...…”

Tuneable Transient Thermogels Mediated by a pH‐ and Redox‐Regulated Supramolecular Polymerization

“…[1] Thes uccessful integration of feedback-driven or multiple coupled equilibria into supramolecular self-assembly processes has led to non-equilibrium kinetically controlled processes and dissipative self-assembled materials. [4] Theg roups of Ulijn, [5] Walther, [6] and Miravet [7] used short hydrophobic oligopeptide hydrogelators to develop enzyme-catalyzed transient hydrogel assemblies with at uneable time domain. Fore xample, george and co-workers have shown that an enzyme-catalyzed and nucleoside-triphosphate-fueled system is able to result in at ransient change in the helicity of supramolecular polymers.…”

Dissipative Self‐Assembly of Peptides

“…Walther and coworkers used an elegant method to create dissipative assemblies that make use of shifts in a pH value induced by a reaction cycle (Figure ) . The authors reported a wide range of building blocks that could be coupled to the reaction cycle including peptides.…”

“…The lifetime of the hydrogels could be tuned from minutes to days by adjusting the reaction kinetics. As a result of their transient nature, these gels could be used to block microfluidics channels temporarily …”