Electrochemistry as a Tool for Redox-Based Bio-Information Processing.

Redox, a native modality in biology involving the flow of electrons, energy, and information, is used for energy-harvesting, biosynthesis, immune-defense, and signaling. Because electrons (in contrast to protons) are not soluble in the medium, electron-flow through the redox modality occurs through redox reactions that are sometimes organized into pathways and networks (e.g., redox interactomes). Redox is also accessible to electrochemistry, which enables electrodes to receive and transmit electrons to exchange energy and information with biology. In this Perspective, efforts to develop electrochemistry as a tool for redox-based bio-information processing: to interconvert redox-based molecular attributes into interpretable electronic signals, are described. Using a series of Case Studies, how the information-content of the measurements can be enriched using: diffusible mediators; tuned electrical input sequences; and cross-modal measurements (e.g., electrical plus spectral), is shown. Also, theory-guided feature engineering approaches to compress the information in the electronic signals into quantitative metrics (i.e., features) that can serve as correlating variables for pattern recognition by data-driven analysis are described. Finally, how redox provides a modality for electrogenetic actuation is illustrated. It is suggested that electrochemistry's capabilities to provide real-time, low-cost, and high-content data in an electronic format allow the feedback-control needed for autonomous learning and deployable sensing/actuation.