An official website of the United States government
Abstract Redox is a unique, programmable modality capable of bridging communication between biology and electronics. Previous studies have shown that theE. coliredox-responsive OxyRS regulon can be re-wired to accept electrochemically generated hydrogen peroxide (H2O2) as an inducer of gene expression. Here we report that the redox-active phenolic plant signaling molecule acetosyringone (AS) can also induce gene expression from the OxyRS regulon. AS must be oxidized, however, as the reduced state present under normal conditions cannot induce gene expression. Thus, AS serves as a “pro-signaling molecule” that can be activated by its oxidation—in our case by application of oxidizing potential to an electrode. We show that the OxyRS regulon is not induced electrochemically if the imposed electrode potential is in the mid-physiological range. Electronically sliding the applied potential to either oxidative or reductive extremes induces this regulon but through different mechanisms: reduction of O2to form H2O2or oxidation of AS. Fundamentally, this work reinforces the emerging concept that redox signaling depends more on molecular activities than molecular structure. From an applications perspective, the creation of an electronically programmed “pro-signal” dramatically expands the toolbox for electronic control of biological responses in microbes, including in complex environments, cell-based materials, and biomanufacturing.
more »
« less
Redox-enabled electronic interrogation and feedback control of hierarchical and networked biological systems
Abstract Microelectronic devices can directly communicate with biology, as electronic information can be transmitted via redox reactions within biological systems. By engineering biology’s native redox networks, we enable electronic interrogation and control of biological systems at several hierarchical levels: proteins, cells, and cell consortia. First, electro-biofabrication facilitates on-device biological component assembly. Then, electrode-actuated redox data transmission and redox-linked synthetic biology allows programming of enzyme activity and closed-loop electrogenetic control of cellular function. Specifically, horseradish peroxidase is assembled onto interdigitated electrodes where electrode-generated hydrogen peroxide controls its activity.E. coli’s stress response regulon,oxyRS, is rewired to enable algorithm-based feedback control of gene expression, including an eCRISPR module that switches cell-cell quorum sensing communication from one autoinducer to another—creating an electronically controlled ‘bilingual’ cell. Then, these disparate redox-guided devices are wirelessly connected, enabling real-time communication and user-based control. We suggest these methodologies will help us to better understand and develop sophisticated control for biology.
more »
« less
- Award ID(s):
- 2227598
- PAR ID:
- 10519383
- Publisher / Repository:
- Nature
- Date Published:
- Journal Name:
- Nature Communications
- Volume:
- 14
- Issue:
- 1
- ISSN:
- 2041-1723
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
We report a novel strategy for bridging information transfer between electronics and biological systems within microdevices. This strategy relies on our “electrobiofabrication” toolbox that uses electrode-induced signals to assemble biopolymer films at spatially defined sites and then electrochemically “activates” the films for signal processing capabilities. Compared to conventional electrode surface modification approaches, our signal-guided assembly and activation strategy provides on-demand electrode functionalization, and greatly simplifies microfluidic sensor design and fabrication. Specifically, a chitosan film is selectively localized in a microdevice and is covalently modified with phenolic species. The redox active properties of the phenolic species enable the film to transduce molecular to electronic signals ( i.e. , “molectronic”). The resulting “molectronic” sensors are shown to facilitate the electrochemical analysis in real time of biomolecules, including small molecules and enzymes, to cell-based measurements such as cytotoxicity. We believe this strategy provides an alternative, simple, and promising avenue for connecting electronics to biological systems within microfluidic platforms, and eventually will enrich our abilities to study biology in a variety of contexts.more » « less
-
Abstract Redox provides unique opportunities for interconverting molecular/biological information into electronic signals. Here, the fabrication of a 3D‐printed multiwell device that can be interfaced into existing laboratory instruments (e.g., well‐plate readers and microscopes) to enable advanced redox‐based spectral and electrochemical capabilities is reported. In the first application, mediated probing is used as a soft sensing method for biomanufacturing: it is shown that electrochemical signal metrics can discern intact mAbs from partially reduced mAb variants (fragmentation), and that these near‐real‐time electrical measurements correlate to off‐line chemical analysis. In the second application,operandospectroelectrochemical measurements are used to characterize a redox‐active catechol‐based hydrogel film: it is shown that electron transfer into/from the film correlates to the molecular switching of the film's redox state with the film's absorbance increasing upon oxidation and the film's fluorescence increasing upon reduction. In the final example, a synthetic biofilm containing redox‐responsiveE. coliis electro‐assembled: it is shown that gene expression can be induced under reducing conditions (via reductive H2O2generation) or oxidative conditions (via oxidation of a phenolic redox‐signaling molecule). Overall, this work demonstrates that 3D printing allows the fabrication of bespoke electrochemical devices that can accelerate the understanding of redox‐based phenomena in biology and enable the detection/characterization redox activities in technology.more » « less
-
Abstract We report the electrochemically switchable reactivity of (salfen)Al(OiPr) (salfen = 1,1′‐di(2,4‐bis‐tert‐butyl‐salicylimino)ferrocene) toward the ring‐opening polymerization of various cyclic esters, ethers, and carbonates. Using a recently developed electrochemical system comprised of an H‐cell and a glassy carbon working electrode, an applied potential can alternate between the two redox states of the catalyst and alter monomer incorporation during ring‐opening polymerization. We discuss differences in activity and control under electrochemical conditions compared to previously studied chemical redox methods and discuss the necessity of a redox switch during certain copolymerization reactions.more » « less
-
Abstract Background Microbial co-cultures and consortia are of interest in cell-based molecular production and even as “smart” therapeutics in that one can take advantage of division of labor and specialization to expand both the range of available functions and mechanisms for control. The development of tools that enable coordination and modulation of consortia will be crucial for future application of multi-population cultures. In particular, these systems would benefit from an expanded toolset that enables orthogonal inter-strain communication. Results We created a co-culture for the synthesis of a redox-active phenazine signaling molecule, pyocyanin (PYO), by dividing its synthesis into the generation of its intermediate, phenazine carboxylic acid (PCA) from the first strain, followed by consumption of PCA and generation of PYO in a second strain. Interestingly, both PCA and PYO can be used to actuate gene expression in cells engineered with the soxRS oxidative stress regulon, although importantly this signaling activity was found to depend on growth media. That is, like other signaling motifs in bacterial systems, the signaling activity is context dependent. We then used this co-culture’s phenazine signals in a tri-culture to modulate gene expression and production of three model products: quorum sensing molecule autoinducer-1 and two fluorescent marker proteins, eGFP and DsRed. We also showed how these redox-based signals could be intermingled with other quorum-sensing (QS) signals which are more commonly used in synthetic biology, to control complex behaviors. To provide control over product synthesis in the tri-cultures, we also showed how a QS-induced growth control module could guide metabolic flux in one population and at the same time guide overall tri-culture function. Specifically, we showed that phenazine signal recognition, enabled through the oxidative stress response regulon soxRS, was dependent on media composition such that signal propagation within our parsed synthetic system could guide different desired outcomes based on the prevailing environment. In doing so, we expanded the range of signaling molecules available for coordination and the modes by which they can be utilized to influence overall function of a multi-population culture. Conclusions Our results show that redox-based signaling can be intermingled with other quorum sensing signaling in ways that enable user-defined control of microbial consortia yielding various outcomes defined by culture medium. Further, we demonstrated the utility of our previously designed growth control module in influencing signal propagation and metabolic activity is unimpeded by orthogonal redox-based signaling. By exploring novel multi-modal strategies for guiding communication and consortia outcome, the concepts introduced here may prove to be useful for coordination of multiple populations within complex microbial systems.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript
- Journal Article:
- https://doi.org/10.1038/s41467-023-44223-w
