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Effect of three enzymes on signal after varying times of S. oneidensis current generation. Electrodes modified with the cells are held at 0.2 V vs AgCl/Ag for varying lengths of time, followed by treatment with one of the enzymes. The change in current output is quantified as a percent signal remaining as compared to the original signal. Nuclease (DNase I, red), a restriction enzyme that binds the DNA sequence on the electrode (HinIF, blue), and a restriction enzyme that does not bind the DNA sequence on the electrode (EcoRI, gray) are compared. Error bars represent the error from 3 biological replicates.
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As fossil fuels are increasingly linked to environmental damage, the development of renewable, affordable biological alternative fuels is vital. Shewanella oneidensis is often suggested as a potential component of bioelectrochemical cells because of its ability to act as an electron donor to metal surfaces. These microbes remain challenging to impl...
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Citations
... [31] Imaging applications have also been developed. [32,33] But only a few studies have reported the inclusion of DNA oligonucleotides on bacterial cell surfaces: lipid-DNA conjugates for selective detection of bacteria by microscopy, [34] aldehyde-hydrazine condensation for S. oneidensis attachment to coated electrode surfaces to produce electricity, [35,36] DNA polymers to encapsulate bacteria, [37] DNA origami nanostructures as a vehicle to deliver antimicrobial agent, [38] aptamer or DNA-small molecule conjugates for cancer therapy application. [39,40] A significant drawback of DNA engineered systems is their susceptibility to nuclease-mediated degradation. ...
Chemical cell surface modification is a fast‐growing field of research, due to its enormous potential in tissue engineering, cell‐based immunotherapy, and regenerative medicine. However, engineering of bacterial tissues by chemical cell surface modification has been vastly underexplored and the identification of suitable molecular handles is in dire need. We present here, an orthogonal nucleic acid‐protein conjugation strategy to promote artificial bacterial aggregation. This system gathers the high selectivity and stability of linkage to a protein Tag expressed at the cell surface and the modularity and reversibility of aggregation due to oligonucleotide hybridization. For the first time, XNA (xeno nucleic acids in the form of 1,5‐anhydrohexitol nucleic acids) were immobilized via covalent, SNAP‐tag‐mediated interactions on cell surfaces to induce bacterial aggregation.
... To enhance electrode colonization on specific metal surfaces, cells have been engineered to display extracellular matrix proteins fused to metal-binding peptides (Suo et al., 2020). Additionally, cells have been engineered to display DNA sequences that could hybridize with complementary sequences that have been selectively deposited onto surfaces (Furst et al., 2018). ...
Biology leverages a range of electrical phenomena to extract and store energy, control molecular reactions and enable multicellular communication. Microbes, in particular, have evolved genetically encoded machinery enabling them to utilize the abundant redox‐active molecules and minerals available on Earth, which in turn drive global‐scale biogeochemical cycles. Recently, the microbial machinery enabling these redox reactions have been leveraged for interfacing cells and biomolecules with electrical circuits for biotechnological applications. Synthetic biology is allowing for the use of these machinery as components of engineered living materials with tuneable electrical properties. Herein, we review the state of such living electronic components including wires, capacitors, transistors, diodes, optoelectronic components, spin filters, sensors, logic processors, bioactuators, information storage media and methods for assembling these components into living electronic circuits.
... To overcome this issue, one strategy recently found was the control of the microorganism adhesion on conductive material surfaces by DNA hybridization. 72 The bacterial cells functionalized with DNA on their surface are immobilized on the electrode surface with previously coupled complementary DNA. The DNA is responsible for transferring electrons from the cells to the electrode surface. ...
... This method provides a new strategy of rapidly forming electroactive layers of cells on electrodes with more control, reproducibility, and high levels of current generation from low densities of cells to produce anodes for BFCs. 72 A single-cell electron collector is another recently developed strategy for wiring-up electronic abiotic/biotic interfaces and generating high power output. 73 Coating the bacterial outer membrane surface by in situ polymerization of dopamine promoted the electron transfer rate from individual living cells to a solid electrode. ...
Interest in developing and applying emerging biomaterials to sensing and energy devices’ frameworks has dramatically climbed in recent years. The world has been recently threatened by the COVID-19 pandemic, generating a sprint for reliable manufacturing and analysis, low-cost detection methods. The challenge is implied in the elaboration of innovative materials and the design of biointerfaces to thrive in the sensing objectives. Concomitantly, the global search for economic growth and recovery is rebounding on energy demand, surpassing growth in energy generation from renewable sources. Therefore, efforts are being focused on the conception and application of biomaterials for the eco-friendly generation, storage, and conversion of energy. Here, we offer some highlights of the rational design of biomaterials and challenges to be overcome in the near future for the commercial consolidation of biodevices in these two segments.
... [20] In this context, electrochemical conjugation has been proposed as an efficient method to produce DNA-modified surfaces with great control over the density and stability; however, this excellent strategy also requires an initial chemical modification step and has only been demonstrated on gold or metal surfaces. [21] Therefore, it is of fundamental importance to develop efficient, stable, and less complex routes for the modification of aptamers on carbon surfaces. ...
Interfacing aptamers with carbon fiber microelectrodes (CFEs) provides a versatile platform to probe the chemical activity in a living brain at the molecular level. However, new approaches are needed for the efficient and stable modification of electrode surfaces with aptamers. Here, we present an electrochemical conjugation strategy to covalently couple aptamers onto CFEs with high chemoselectivity, efficiency, and stability for sensing in the brain. The strategy employs an initial electrochemical coupling of catechol on an CFE, thereby generating a thin layer of quinone intermediates that couple rapidly with thiol‐containing oligonucleotides under a controlled potential. This approach dramatically simplifies and improves the efficiency for modifying carbon surfaces, thereby allowing direct conjugation of high levels of aptamers on CFEs within 5 minutes. Importantly, the covalent linkage between the aptamers and carbon surfaces enables a greatly improved sensitivity and stability for the sensing of dopamine, offering a robust system for continuously probing dopamine dynamics in the living brains of animals.
... [20] In this context, electrochemical conjugation has been proposed as an efficient method to produce DNA-modified surfaces with great control over the density and stability; however, this excellent strategy also requires an initial chemical modification step and has only been demonstrated on gold or metal surfaces. [21] Therefore, it is of fundamental importance to develop efficient, stable, and less complex routes for the modification of aptamers on carbon surfaces. ...
Interfacing aptamers with carbon fiber microelectrodes (CFEs) provides a versatile platform to probe the chemical activity in living brain at the molecular level. However, new chemistries are needed for efficient and stable modifying aptamers on electrode surfaces. Here, we present an electrochemical conjugation strategy to covalent couple aptamers onto CFEs with high chemoselectivity, efficiency, and stability for sensing in the brain. The strategy employs an initial electrochemical coupling of catechol on CFE, generating a thin layer of quinone intermediates that couple rapidly with thiol‐containing oligonucleotides under a controlled potential. This approach dramatically simplifies and improves the efficiency for modification on carbon surfaces, allowing direct conjugation of high levels of aptamers on CFE within 5 minutes. Importantly, the covalent linkage between aptamers and carbon surfaces enables a greatly improved sensitivity and stability in sensing of dopamine, offering a robust system for continuously probing dopamine dynamics in living brain of animals.
... This overlap further allows the DNA to conduct electrons as a molecular wire. [39][40][41] These properties have brought new opportunities in materials science, 34,42 sensing, and diagnostics. [43][44][45] Among them, DNA "Velcro" has been used to pattern cells 39,46-50 and antibodies. ...
Electrochemical reduction of carbon dioxide (CO2) is a promising route for the up-conversion of this industrial by-product. However, to perform this reaction with a small-molecule catalyst, the catalyst must be proximal to an electrode surface. Efforts to immobilize these catalysts on electrodes have been stymied by the need to optimize immobilization chemistries on a case-by-case basis. As with many reactions, Nature has evolved catalysts with high specificity, selectivi-ty, and activity. By taking inspiration from biological porphyrins and combining it with the specificity of DNA hybridiza-tion, we have developed an improved electrocatalyst platform for CO2 reduction. The addition of single-stranded DNA to the porphyrin-based catalysts improved their stability, and DNA-catalyst conjugates were immobilized on screen-printed carbon electrodes using DNA hybridization with nearly 100% efficiency. Increased turnover frequency (TOF) and catalyst stability were observed with the DNA-immobilized catalysts as compared to the unmodified small molecules. This work demonstrates the importance of taking inspiration from Nature and demonstrates the potential of DNA hybridization as a general strategy for molecular catalyst immobilization.
... We previously demonstrated that DNA hybridization between DNAmodified electrodes and DNA-modified cells enabled rapid current generation on gold electrodes. 31 Here, we sought to expand the application of that technology to carbon SPEs. Conventionally, S. oneidensis bioreactors require carbon cloth for current production, which has a high surface area to volume ratio and a significant three-dimensional structure, allowing for better colonization by these cells. ...
Modification of electrodes with biomolecules is an essential first step for the development of biosensors. Conventionally, gold electrodes are used because of their ease of modification with thiolated biomolecules. However, carbon screen-printed electrodes (SPEs) are gaining popularity for the development of cost-effective platforms, as they do not require precious metals for the work-ing electrode and are more consistent than most equivalent gold screen-printed electrodes. However, their universal modification with biomolecules remains a challenge; the majority of work to-date relies on non-specific amide bond formation to chemical handles on the electrode surface. By combining facile and consistent electrochemical modification to add an aniline handle to elec-trodes with a specific and biocompatible bioorthogonal oxidative coupling reaction, we can attach DNA and proteins to carbon electrodes. Importantly, for both proteins and DNA, the biomolecules maintain activity following coupling, ensuring that the DNA is in a biologically-relevant conformation and that proteins remain folded following coupling. We have further demonstrated the ability to generate self-assembled whole-cell films on these electrodes using DNA-directed immobilization to DNA-modified elec-trodes. This work provides an important platform for the modification of inexpensive carbon SPEs and is anticipated to be appli-cable to any carbon-based electrode material.
... Prior efforts to direct electroactive biofilm formation on surfaces have focused solely on engineering cell-electrode attachment, rather than patterning, through synthetic biology and materials engineering strategies. These works were based on either (I) enhancing biofilm formation by expressing adhesive appendages on cell surfaces 49,50 and increasing c-di-GMP levels 51, 52 or (II) placing complementary chemical or DNA-based structures on substrates and cell surfaces to bond cells to electrodes [53][54][55][56][57] . Compared with these previous works, our strategy does not require electrode pretreatment for electroactive biofilm patterning and can generate robust biofilms with defined dimensions. ...
Electroactive bacterial biofilms can function as living biomaterials that merge the functionality of living cells with electronic components. However, the development of such advanced living electronics has been challenged by the inability to control the geometry of electroactive biofilms relative to solid-state electrodes. Here, we developed a lithographic strategy to pattern conductive biofilms of Shewanella oneidensis by controlling aggregation protein CdrAB expression with a blue light-induced genetic circuit. This controlled deposition enabled S. oneidensis biofilm patterning on transparent electrode surfaces and measurements demonstrated tunable biofilm conduction dependent on pattern size. Controlling biofilm geometry also enabled us, for the first time, to quantify the intrinsic conductivity of living S. oneidensis biofilms and experimentally confirm predictions based on simulations of a recently proposed collision-exchange electron transport mechanism. Overall, we developed a facile technique for controlling electroactive biofilm formation on electrodes, with implications for both studying and harnessing bioelectronics.
... Recent efforts have been made to chemically engineer the abiotic-biotic interface in these systems, including through the introduction of deoxyribonucleic acid (DNA) hybridization-based cell adhesion to attach EAMs to electrodes. 8 Although significant progress has been made to understand the fundamental biology of electroactive cells and apply that knowledge to EMP, EET-EMP technologies remain limited to proof-of-concept systems. ...
Microbial electrosynthesis is increasingly popular, as it couples renewable electricity to microbial metabolism. Currently, electromicrobial production (EMP) to synthesize fuels has yet to surpass laboratory-scale reactions, but continuing improvements in the cost efficiency of these technologies hold promise for their translation to the real world. In this issue of Joule, Barstow and coworkers introduce a computational framework to determine the maximum efficiency of EMP, providing a blueprint for the scaling and broad implementation of these unique, renewable energy systems.
Electrochemical reduction of carbon dioxide (CO2) is a promising route to up-convert this industrial byproduct. However, to perform this reaction with a small-molecule catalyst, the catalyst must be proximal to an electrode surface. Efforts to immobilize molecular catalysts on electrodes have been stymied by the need to optimize the immobilization chemistries on a case-by-case basis. Taking inspiration from nature, we applied DNA as a molecular-scale “Velcro” to investigate the tethering of three porphyrin-based catalysts to electrodes. This tethering strategy improved both the stability of the catalysts and their Faradaic efficiencies (FEs). DNA-catalyst conjugates were immobilized on screen-printed carbon and carbon paper electrodes via DNA hybridization with nearly 100% efficiency. Following immobilization, a higher catalyst stability at relevant potentials is observed. Additionally, lower overpotentials are required for the generation of carbon monoxide (CO). Finally, high FE for CO generation was observed with the DNA-immobilized catalysts as compared to the unmodified small-molecule systems, as high as 79.1% FE for CO at −0.95 V vs SHE using a DNA-tethered catalyst. This work demonstrates the potential of DNA “Velcro” as a powerful strategy for catalyst immobilization. Here, we demonstrated improved catalytic characteristics of molecular catalysts for CO2 valorization, but this strategy is anticipated to be generalizable to any reaction that proceeds in aqueous solutions.
