Network-based redox communication between abiotic interactive materials

Recent observations that abiotic materials can engage in redox-based interactive communication motivates the search for new redox-active materials. Here we fabricated a hydrogel from a four-armed thiolated polyethylene glycol (PEG-SH) and the bacterial metabolite, pyocyanin (PYO). We show that: (i) the PYO-PEG hydrogel is reversibly redox-active; (ii) the molecular-switching and directed electron flow within this PYO-PEG hydrogel requires both a thermodynamic driving force (i.e., potential difference) and diffusible electron carriers that serve as nodes in a redox network; (iii) this redox-switching and electron flow is controlled by the redox network's topology; and (iv) the ability of the PYO-PEG hydrogel to transmit electrons to a second insoluble redox-active material (i.e., a catechol-PEG hydrogel) is context-dependent (i.e., dependent on thermodynamic driving forces and appropriate redox shuttles). These studies provide an experimental demonstration of important features of redox-communication and also suggest technological opportunities for the fabrication of interactive materials.

Automated summary

Recent observations suggest that abiotic materials can engage in interactive communication through redox reactions. In this study, a hydrogel made from four-armed thiolated polyethylene glycol (PEG-SH) and the bacterial metabolite pyocyanin (PYO) was fabricated and shown to exhibit reversible redox activity. The study also highlighted the significance of the redox network's topology in controlling molecular switching and electron flow within the hydrogel.