Mediated Electrochemical Probing: A Systems-Level Tool for Redox Biology

Abstract

Biology uses well-known redox mechanisms for energy harvesting (e.g., respiration), biosynthesis, and immune defense (e.g., oxidative burst), and now we know biology uses redox for systems-level communication. Currently, we have limited abilities to "eavesdrop" on this redox modality, which can be contrasted with our abilities to observe and actuate biology through its more familiar ionic electrical modality. In this Perspective, we argue that the coupling of electrochemistry with diffusible mediators (electron shuttles) provides a unique opportunity to access the redox communication modality through its electrical features. We highlight previous studies showing that mediated electrochemical probing (MEP) can "communicate" with biology to acquire information and even to actuate specific biological responses (i.e., targeted gene expression). We suggest that MEP may reveal an extent of redox-based communication that has remained underappreciated in nature and that MEP could provide new technological approaches for redox biology, bioelectronics, clinical care, and environmental sciences.

Characterizing Electron Flow through Catechol‐Graphene Composite Hydrogels

“…[10] In aqueous systems, electron-transfer is constrained by the solvent and typically occurs through at least two distinctly different mechanisms each of which favors different types of materials. [11][12][13] One electron-transfer mechanism is a metal-like conductivity. [14,15] Carbon-based nanomaterials have been especially important for conferring such conductivity [14,16] with benefits that include enhanced double layer charge storage for energy applications [17][18][19][20][21] and electrocatalytic properties for sensing applications.…”

Network-based redox communication between abiotic interactive materials

“…We envision that this work will enable the development of more complex redox-based communication networks that will allow us to both understand how information flows through biological interactomes and also how to participate in this information flow. We believe that these capabilities will be especially important for the emerging field of redox-based bioelectronics where redox is being used as the modality that allows both the sensing and actuation of biological activities ( Stephens et al., 2021 ; Terrell et al., 2021 ; Zhao et al., 2021 ).…”

System-Level Network Analysis of a Catechol Component for Redox Bioelectronics

“…Conventional ion-based bioelectronics often connects through biology’s neuromuscular systems with particular successes involving cardiovascular health: The system-level status can be readily observed (e.g., by an EKG), maintained (e.g., by a pacemaker), and adjusted (e.g., by a defibrillator). In contrast, redox-based bioelectronics offers the opportunity to connect through other biological systems (e.g., the immune system) and targets other applications such as the system-level measurement of oxidative stress − and the actuation of gene expression (electrogenetics). − …”

“…The experimental method used in this study is mediated electrochemical probing (MEP), which is emerging as an important system-level method for redox biology. ,, Typically for MEP, Scheme b shows that diffusible mediators (i.e., nodes) are purposefully added to an experimental system and then an electrode is used to impose tailored voltage inputs that induce electrons to flow through the interactome. When MEP is used for sensing, the mediator and voltage inputs are designed to evoke readily measurable output responses that reveal network topology-dependent features.…”