Bioresource technology • 2026

This study investigated the effects of Fe-Mn MOF-derived carbon composite (Fe-Mn MDC) on anaerobic digestion (AD) performance of food waste (FW) and elucidated the underlying mechanisms. The methane yield increased to 457.44 ± 14.21 mL/g VS under 0.05 g/g TS Fe-Mn MDC addition, representing a 36.47 % increase compared to the control group. Metagenomics analysis indicated that Fe-Mn MDC altered the microbial community structure, enriched the abundance and mutualism of exoelectrogenic bacteria (Geobacter) and electroactive methanogenic microorganisms (Methanothrix) involved in direct interspecies electron transfer. The metabolic activity of hydrogenotrophic methanogens was enhanced under Fe-Mn MDC addition, and the content of dehydrogenase and coenzyme F420 was also stimulated, thereby accelerating substrate consumption and methane production. The physicochemical characterization results of Fe-Mn MDC demonstrated that it could act as an electron shuttle and facilitate proton transfer. Besides, AD system exhibited not only an increase in e-pili and c-type genes abundance, but also an enhanced representation of gene modules linked to the biosynthesis of V/A-type ATPases (M00159) and F-type (M00157), which further indicated that Fe-Mn MDC enhanced the proton-coupled electron transfer in AD system. These results provided potential applications in FW management and new insights into the mechanism of renewable energy recovery from AD.

3 Biotech • 2025

Petroleum refinery wastewater (PRWW) with 4% salinity was subjected to treatment and simultaneous generation of energy in air cathode-microbial fuel cell (MFC). Substrate load (SL) such as 0.41 gCOD/L, 0.84 gCOD/L, 1.26 gCOD/L, 1.78 gCOD/L and 2.25 gCOD/L was trialed in air cathode MFC. COD (chemical oxygen demand) reduction was 88% (total COD) and 87% (soluble COD) at optimized SL of 1.78 gCOD/L. Corresponding power and current density derived at optimized SL of 1.78 gCOD/L was 879 mW/m 2 and 1052 mA/m 2 respectively. Degradation of low and high molecular weight petroleum hydrocarbons in the PRWW was greater than 90% to 100%  and 71% to 82% respectively. Supplementation with a mild nutritional substrate in PRWW accelerated the hydrocarbon biodegradation with time reduction in MFC operated at 1.78 gCOD/L SL. Phylogenetic analysis revealed the dominancy of exo-electrogenic halophilic strains such as Ochrobactrum , Marinobacter , Bacillus and Stenotrophomonas in the reactor. Thus the bioaugmentation of halophiles in MFC efficiently treated PRWW and harvested bioenergy under saline condition.

[object Object], [object Object], [object Object] et al.

Scientific Reports • 2025

The pathogenic profiles of seven Shewanella spp. positive cases identified during diarrhea surveillance in Beijing, China, in 2023 were characterised. Sentinel hospitals collected patient information and stool samples, while regional centres for disease control (CDC) performed cultures and real time PCR. Whole-genome sequencing (WGS), average nucleotide identity (ANI) analysis, phylogenetic analysis, virulence gene and resistance gene analysis of the Shewanella spp. isolates were conducted, as well as phenotypic resistance analysis. The detection rate in the stool samples collected from 354 diarrhea patients was 1.98% (7/354). The time of disease onset of six out of the seven patients ranged from July 17–22, 2023. The incubation period ranged from 8 to 12 h with 3–50 episodes/day. Three subjects reported having consumed potentially contaminated seafood. The seven isolated strains of Shewanella spp. (named as S1-S7) were closely related to S. algae, belonged to the algae clade, and were all novel ST (sequence typing) strains. A total of 125,738 SNPs (single nucleotide polymorphism) were identified in the core genomes of the seven Shewanella strains. Twenty-six virulence-related genes in five categories were identified, with chemotaxis and flagella-related genes being the most abundant (26.92%, 7/26), followed by secretion system- and serum resistance-related genes at 23.08% (6/26) and 15.38% (4/26), respectively. Shewanella spp. were detected in patients with diarrhea at a certain level. Seafood should be the key food category for monitoring and seafood markets should become a key monitoring site for Shewanella spp. The novel STs of the algae clade isolated from diarrhea patients in this study may potentially help in tracking circulating strains. Further in-depth investigations are required to precisely elucidate the correlation between Shewanella infections and human diarrhea and the pathogenic characteristics of this infection.

[object Object], [object Object], [object Object] et al.

Bioelectrochemistry • 2025

Unconventional natural gas pipeline corrosion is associated with microbes, especially sulfate-reducing bacteria (SRB), though it is uncertain if SRB's role is overemphasized. Using metagenomics, corrosion immersion, and microbial cultivation, diverse hydrocarbon-degrading microorganisms, such as Shewanella, in corroded pipeline rust layers, oil-water mixtures, and produced water from unconventional natural gas fields are identified. These bacteria use crude oil as a carbon source, accelerating pitting corrosion of carbon steel and forming corrosion product films (Pitmax = 28.96 μm). The 16S rRNA sequencing results show that Shewanella, prevalent in various steel service environments, is a potential key microorganism in pipeline corrosion. X70 steel exhibits lower electron transfer resistance than Desulfovibrio in the Shewanella medium. Shewanella's aerobic respiration degrades crude oil and oxidizes iron, speeding up iron oxide formation and magnesium phosphate precipitation. Microbial acidification of the oil-water medium also contributes to severe pitting corrosion beneath the oil film. Crude oil accelerates microbial growth. Thus, studying carbon steel corrosion in oil-water environments must consider the impact of hydrocarbon-degrading microorganisms.

[object Object], [object Object], [object Object] et al.

ACS Nano • 2025

The toxicity of negatively charged nanoplastics (NNP) to bacteria is generally subtler than that of positively charged counterparts, owing to limited NNP-cell interaction. This study hypothesized that common environmental cations (Na+, Mg2+, Ca2+) could enhance interaction between NNP and Shewanella oneidensis, thereby inducing biological effects. Settling experiments and dynamic light scattering analyses showed that NNP-cell interaction increased in the order of Ca2+ ≈ Mg2+ > Na+, which can be attributed to the decreased electrostatic repulsion, as confirmed by extended Derjaguin-Landau-Verwey-Overbeek theory calculations. Although coexposure to NNP and cations did not result in significant lethality, extracellular electron transfer (EET) to insoluble electron acceptors was significantly inhibited by coexposing to NNP and Ca2+ (NNP+Ca2+, by 37%) or Mg2+ (NNP+Mg2+, by 20%), but not by NNP alone or NNP and Na+ treatments. Two-dimensional correlation spectroscopy indicated that membrane proteins predominantly mediate bacterial interactions with NNP. Physical membrane damage and structural alterations of membrane proteins were observed following coexposure to NNP+Ca2+ and NNP+Mg2+, impairing the direct EET pathways. Transcriptomic and physiological analyses further revealed that NNP+Ca2+ upregulated persister marker genes (spoT, ppx, relA) and induced ATP depletion, triggering cellular dormancy and suppressing membrane protein-mediated processes. By contrast, NNP+Mg2+ exposure activated protective responses, including two-component systems and flagellar assembly, consistent with the milder impairment of EET. Notably, these effects were absent in treatments with either cations alone or NNP alone. These findings reveal an overlooked ecological impact of NNP and underscore the potential for distinct bacterial responses to NNP in varying aquatic environments.

[object Object], [object Object], [object Object] et al.

Antimicrobial Agents and Chemotherapy • 2025

ABSTRACT Tigecycline is a last resort antibiotic that is used to treat serious infections; however, some bacteria have developed tigecycline resistance by producing a tigecycline-inactivating enzyme or tigecycline resistance efflux pump, encoded by tet(X) and tmexCD-toprJ genes, respectively. Tons of seafood are consumed annually in China; however, whether seafood harbors tigecycline-resistant bacteria is not known. In this study, we isolated various tigecycline-resistant bacteria from retail seafood; among these, Shewanella was the predominant tigecycline-resistant genus (33/76, 43.4%). Genomic sequencing revealed that two Shewanella strains carried the tet(X4) gene, while one Shewanella chilikensis strain co-harbored tmexCD2-toprJ2 and blaNDM-1 genes. The tet(X4) and tmexCD2-toprJ2 were found to be located on novel members of the SXT/R391 family of integrated conjugative elements (ICEs). As per our knowledge, this is the first report on the emergence of SXT/R391 ICEs carrying tet(X4) or tmexCD2-toprJ2 gene in Shewanella strains. The SXT/R391 family ICEs could mediate the spread of tigecycline resistance genes among aquatic bacteria, and contact between seafood and consumers may lead to the dissemination of tigecycline-resistant bacteria. Our study revealed that Shewanella spp. may act as potential reservoirs of tigecycline resistance genes.

[object Object], [object Object], [object Object] et al.

Microbial Genomics • 2025

Graphical Abstract Comparative genomic analysis revealed that I-F3 CASTs serve as important mobile genetic elements mediating horizontal transfer of functional genes associated with defence, resistance and electron transfer in Shewanella. The transposition function of a new I-F3 CAST variant carried by strain ANA-3 was assessed both endogenously and heterologously.

[object Object], [object Object], [object Object] et al.

Journal of Microbiology and Biotechnology • 2025

Vanadium dioxide (VO2) nanoparticles have various application potentials such as smart windows and electronic devices due to their unique phase transition properties. However, conventional VO2 synthesis methods require harsh conditions and toxic reducing agents, leading to environmental problems. In this study, we developed an eco-friendly method to biosynthesize VO2 nanoparticles using Shewanella sp. strain HN-41 under anaerobic conditions at 30°C and neutral pH. Morphological observations revealed that biogenic VO2 nanoparticles with an average size of 4.3 nm were in the form of granules presented inside and outside the cells. These nanoparticles were identified as VO2 by differential scanning calorimetry (DSC) analysis, which showed a phase transition temperature of 61.9°C, consistent with that of VO2. Furthermore, we observed an active formation of vesicles containing VO2 nanoparticles by the cross-sectioned transmission electron microscopy (TEM) analysis. Thus, in addition to the direct extracellular formation of VO2 nanoparticles through anaerobic respiration, bacterial membrane vesicles likely play a role in expelling nanoparticles from the cell, potentially mitigating their toxicity. These findings highlight metal reducing bacteria could be a biological green agent for the production of valuable VO2 nanoparticles under anaerobic environmental conditions.

[object Object], [object Object], [object Object] et al.

Protein Science • 2025

The Gram‐negative Shewanellaceae family is well known for its ability to transfer catabolically derived electrons to extracellular terminal electron acceptors through electron conduits that permeate the outer membrane. The primary conduit is MtrCAB, a trimeric porin‐cytochrome complex that contains the cell surface exposed decaheme cytochrome MtrC. This donates electrons to extracellular substrates, including OmcA, soluble metals, organic electron shuttles, and insoluble metal oxides. However, it is not clear whether this broad substrate specificity requires specific sites for binding and reduction, or whether reduction occurs through non‐specific interactions near exposed hemes on the cytochrome surface. Shewanella oneidensis MtrC is composed of four domains, with the hemes closely packed and distributed evenly between domains II and IV. The domains are arranged to allow electron transport across the cytochrome via interdomain electron transfer, but the significance of this conserved feature is not understood. Here we use site‐directed mutagenesis to generate an MtrC variant that is comprised only of domains I and II (MtrCDI,II). The properties of this MtrCDI,II are effectively identical to domains I and II of full‐length MtrC. Whole‐cell assays revealed that S. oneidensis cells replacing full‐length MtrC with MtrCDI,II had significantly lower rates of OmcA, flavin mononucleotide, and Fe(III) citrate reduction. Our results demonstrate that MtrC domains III and IV contain sites for association of specific substrates, enabling the reduction of extracellular electron acceptors in S. oneidensis.

[object Object], [object Object], [object Object] et al.

eLife • 2025

Lysogens, bacteria with one or more viruses (prophages) integrated into their genomes, are abundant in the gut of animals. Prophages often influence bacterial traits; however, the influence of prophages on the gut microbiota–host immune axis in animals remains poorly understood. Here, we investigate the influence of the prophage SfPat on Shewanella fidelis 3313, a persistent member of the gut microbiome of the model marine tunicate, Ciona robusta. Establishment of a SfPat deletion mutant (ΔSfPat) reveals the influence of this prophage on bacterial physiology in vitro and during colonization of the Ciona gut. In vitro, deletion of SfPat reduces S. fidelis 3313 motility and swimming while increasing biofilm formation. To understand the in vivo impact of these prophage-induced changes in bacterial traits, we exposed metamorphic stage 4 Ciona juveniles to wildtype (WT) and ΔSfPat strains. During colonization, ΔSfPat localizes to overlapping and distinct areas of the gut compared to the WT strain. We examined the differential expression of various regulators of cyclic-di-GMP, a secondary signaling molecule that mediates biofilm formation and motility. The pdeB gene, which encodes a bacterial phosphodiesterase known to influence biofilm formation and motility by degrading cyclic-di-GMP, is upregulated in the WT strain but not in ΔSfPat when examined in vivo. Expression of the Ciona gut immune effector, VCBP-C, is enhanced during colonization by ΔSfPat compared to the WT strain; however, VCBP-C binding to the WT strain does not promote the excision of SfPat in an SOS-dependent pathway. Instead, VCBP-C binding significantly reduces the expression of a phage major capsid protein. Our findings suggest that SfPat influences host perception of this important colonizing commensal and highlights the significance of investigating tripartite dynamics between prophages, bacteria, and their animal hosts to better understand the gut microbiota-host immune axis.

[object Object], [object Object], [object Object] et al.

Journal of the American Chemical Society • 2025

The electrical conductivity of biofilms plays a critical role in advancing bioelectronics for energy and environmental applications, yet the underlying mechanisms remain poorly understood. Previous studies proposed interheme electron transfer between hemes 5 and 10 in the outer-membrane deca-heme cytochrome (OMC) MtrC as the rate-limiting step in the biofilm electron conduction of Shewanella oneidensis MR-1. However, the strong interheme electron coupling in MtrC suggests that interprotein interactions may represent the primary barrier to biofilm electron conduction. Here, we investigated the biofilm electron conduction mechanism with a focus on interprotein electron transfer in S. oneidensis MR-1. Conductive currents and their temperature dependence were measured for estimating the thermal activation energy (E a) by using indium tin-doped oxide (ITO) interdigitated electrodes in wild-type and mutant biofilms. While deletion of periplasmic cytochromes had a negligible impact on E a, the deletion of OmcA or MtrC increased E a 3-fold, revealing that interprotein interactions, particularly between OmcA and MtrC, dominate biofilm electron transfer over clonal OMC interactions. Furthermore, suppressing outer-membrane fluidity dramatically increased E a, while interheme exciton coupling negligibly changed in the OMCs, confirming the critical role of protein diffusion and collision on the outer membrane. Flavin binding to OmcA or MtrC reduced conduction currents attributable to heme centers but enhanced those assignable to noncovalently bound flavins, suggesting that flavin occupancy blocks hemes 2 and 7, which serve as key interprotein electron transfer sites. These findings provide a mechanistic foundation for engineering highly conductive biofilms through targeted protein interface optimization, offering new avenues for the development of bioelectronic technologies.

[object Object], [object Object], [object Object] et al.

Microbial Ecology • 2025

Biofilm formation is a survival strategy for bacteria, contributing to their persistence in natural and industrial environments. In this study, we investigated the ability of extracellular products (ECPs) produced by the probiotic strain Shewanella sp. Pdp11 under different culture conditions to inhibit biofilm formation in pathogenic and environmental Shewanella strains. ECPs from specific culture conditions altered biofilm formation in several Shewanella strains, with Shewanella hafniensis P14 displaying the highest sensitivity. Metabolomic analysis of the ECPs identified glycogen as a key metabolite associated with biofilm inhibition. Further genomic analysis of S. hafniensis P14 revealed an interruption in its glycogen synthesis pathway, suggesting a dependency on external glycogen-related metabolites for biofilm development. These findings demonstrate that Shewanella sp. Pdp11 ECPs can modify biofilm formation across multiple Shewanella strains, particularly in S. hafniensis P14 through glycogen-associated mechanisms.

[object Object], [object Object], [object Object] et al.

Fish and Shellfish Immunology • 2025

Recently, the infection with Shewanella spp. results in health disorders and mortalities in Nile tilapia (Oreochromis niloticus). The present trial is proposed to look into the impact of Shewanella spp. infection on the immune responses, antioxidant capacity, target genes expression of autophagy, endoplasmic reticulum stress (ER), and antimicrobial peptides in spleen tissue. As well as the antagonistic effects of chitosan nanogel composite (CNC; 75 μg/L) as a water application against Shewanella spp. infection were studied. One hundred and sixty fish (27.55±1.50 g) were assigned to four groups; each had four replicates for 14 days. The first (CONT) and second (CNC) groups were non-challenged and treated with 0 and 75 μg/L CNC, respectively, where the first was the control. The third (SH) and fourth (CNC+SH) groups were intraperitoneally challenged with 0.20 mL (containing 0.14 × 105 CFU) of Shewanella spp. The outcomes clarified that Shewanella spp. infection induced oxidative stress by lowering the activity of superoxide dismutase and reduced glutathione and increasing the malondialdehyde level. Increases in the serum levels of C-reactive protein, complement-3, and immunoglobulin M were noticed in the Shewanella-infected fish comparable to the CONT. Shewanella infection down-regulated the expression of Beclin-1 and microtubule-associated protein light chain kinase 3 in the spleen, while up-regulated the expression of the mechanistic target of rapamycin and ubiquitin-binding protein. In addition, up-regulation of the ER stress-related genes (CCAAT/enhancer-binding protein homologous protein, c-Jun N-terminal kinase, activating transcription factor 6, X box-binding protein-1, and binding protein for immunoglobulins) and antimicrobial peptides genes (Piscidin 4 and hepcidin antimicrobial peptide 1) were consequences of Shewanella Spp. infection compared to the CONT. On the contrary, CNC water treatment improved the survival of the Shewanella-infected fish (90%) compared to the CONT (77.50%). Moreover, an improvement in the antioxidant capacity and immune responses was noticed when the Shewanella-infected fish were treated with CNC. Modulation of the autophagy, ER stress, and antimicrobial peptide-related genes was noticed by treating the Shewanella-infected fish with CNC. Notably, CNC could be used as a water treatment for controlling the Shewanella challenge in Nile tilapia.

[object Object], [object Object], [object Object] et al.

Microorganisms • 2025

Extracellular electron transport (EET) supports the survival of specific microorganisms on the Earth’s surface by facilitating microbial respiration with diverse electron acceptors. A key aspect of EET is the organization of electron relays, i.e., multi-heme c-type cytochromes (MHCs), within the periplasmic space of microbial cells. In this study, we investigated the mobility of periplasmic electron relays in Shewanella oneidensis MR-1, a model strain capable of EET, using in vivo protein crosslinking to the MHCs. First, we established that crosslinking efficiency correlates with the spatial proximity and diffusion coefficient of protein molecules through in vitro tests. Based on these findings, we identified distinct molecular behaviors of periplasmic MHCs, showing that the tetraheme flavocytochrome FccA, which also serves as a periplasmic fumarate reductase, forms protein complexes with limited motility, while the small tetraheme c-type cytochrome CctA remains discrete and mobile. Both MHCs contribute to EET for bioelectrochemical nitrate and nitrite reduction. These findings reveal dual mechanisms for organizing periplasmic electron relays in EET, advancing our understanding of microbial extracellular respiration.

[object Object], [object Object], [object Object] et al.

Environmental Science: Nano • 2025

Shewanella oneidensis (S. oneidensis) MR-1 is a metal-reducing bacterium that can bio-reduce the carcinogenic hexavalent chromium (Cr6+) to the less toxic trivalent Cr3+. Bio-reduction is assisted by the protective role of Mn-ferrite NPs to bacteria.

[object Object], [object Object], [object Object] et al.

FEMS Microbiology Letters • 2025

Abstract The extracellular electron transport chain of Shewanella oneidensis MR-1 has been well characterized in the context of current generation on an anode. However, work to understand electron uptake from the cathode is less mature and major questions remain regarding the pathway and purpose of electron uptake. To employ this organism as a biocatalyst for microbial electrosynthesis, we must have a clear picture of the path of electrons into the cell to mitigate off-target reactions and find opportunities for pathway improvement. In this work, we confirm that the outer membrane electron conduit MtrCAB is essential for electron uptake, while the inner membrane cytochrome CymA is important but can be partially compensated for by other proteins. Additionally, we show that endogenous flavins are important for electron uptake and their absence cannot be complemented by exogenous flavins. Finally, hydrogenases are not directly involved in electron transfer but may play a role in cell survival during stationary phase on the cathode. Overall, the inward electron transfer pathway largely overlaps with the outward electron transfer pathway although we find differences in the role of flavins, particularly exogenously added riboflavin.

[object Object], [object Object], [object Object] et al.

International Journal of Molecular Sciences • 2025

Egg yolk immunoglobulin Y (IgY) possesses advantages such as low cost, easy availability, simple preparation, high antigen specificity, absence of drug residues, and compliance with animal welfare standards, making it an environmentally friendly and safe alternative to antibiotics. This research utilizes IgY antibody technology to develop a multivalent passive immune vaccine for major pathogenic bacteria in aquaculture. In this study, IgY antibodies against live Shewanella xiamenensis (LSX-IgY) and inactivated S. xiamenensis (ISX-IgY) were prepared by immunizing laying hens, and passive immunization protection experiments were conducted in Carassius auratus infected with S. xiamenensis and Aeromonas hydrophila. The passive immunization protection rates of LSX-IgY and ISX-IgY against S. xiamenensis were 63.64% and 72.73%, respectively, and the passive cross-protection rates against A. hydrophila were 50% and 71.43%, respectively. Further, C. auratus sera could specifically bind to S. xiamenensis or A. hydrophila in vitro, and the phagocytic activity of leukocytes was increased. LSX-IgY and ISX-IgY could reduce the bacterial load in the C. auratus kidneys. Meanwhile, they could significantly reduce the levels of antioxidant factors in serum and inhibit the mRNA expression of inflammation-related factors in the kidneys and spleens. Additionally, histopathology and immunofluorescence analysis showed that both IgY preparations preserved tissue integrity and reduced the expression of apoptosis factor (p53) and DNA damage factor (γH2A.X) of visceral organs, respectively. In summary, LSX-IgY and ISX-IgY can combat various bacterial infections, with no significant difference between the two. Additionally, inactivated bacterial immunization is more aligned with animal welfare standards for laying hens. Therefore, ISX-IgY is expected to serve as a multivalent vaccine against major aquaculture pathogens.

[object Object], [object Object], [object Object] et al.

Microorganisms • 2025

Antibiotic resistance is increasing at an alarming rate worldwide, in large part due to their misuse and improper disposal. Antibiotics administered to treat human and animal diseases, including feed supplements for the treatment or prevention of disease in farm animals, have contributed greatly to the emergence of a multitude of antibiotic-resistant pathogens. Shewanella is one of many bacteria that have developed antibiotic resistance, and in some species, multiple-antibiotic resistance (MAR). Shewanella is a rod-shaped, Gram-negative, oxidase-positive, and H2S-producing bacterium that is naturally found in the marine environment. In humans, Shewanella spp. can cause skin and soft tissue infections, septicemia, cellulitis, osteomyelitis, and ear and wound infections. Some Shewanella have been shown to be resistant to a variety of antibiotics, including beta-lactams, aminoglycoside, quinolones, third- or fourth-generation cephalosporins, and carbapenems, due to the presence of genes such as the blaOXA-class D beta-lactamase-encoding gene, blaAmpC-class-C beta-lactamase-encoding gene, and the qnr gene. Bacteria can acquire and transmit these genes through different horizontal gene-transmission mechanisms such as transformation, transduction, and conjugation. The genes for antibiotic resistance are present on Shewanella chromosomes and plasmids. Apart from this, heavy metals such as arsenic, mercury, cadmium, and chromium can also increase antibiotic resistance in Shewanella due to co-selection processes such as co-resistance, cross resistance, and co-regulation mechanisms. Antibiotics and drugs enter Shewanella spp. through pores or gates in their cell wall and may be ejected from the bacteria by efflux pumps, which are the first line of bacterial defense against antibiotics. Multiple-drug resistant Shewanella can be particularly difficult to control. This review focuses on the phenotypic and genomic characteristics of Shewanella that are involved in the increase in antimicrobial resistance in this bacterium.

[object Object], [object Object], [object Object] et al.

RSC Sustainability • 2025

Graphene sponge enables both cathodic and anodic reactions in microbial fuel cells. This free-standing graphene sponge electrode demonstrates high coulombic efficiency and current density.

[object Object], [object Object], [object Object] et al.

ENERGY & ENVIRONMENTAL MATERIALS • 2026

The persistence of antibiotics such as tetracycline in aquatic systems poses severe environmental and health risks by potential antimicrobial resistance. To address this, a hybrid photo‐electro‐Fenton oxidation system based on MXene‐derived electrodes was developed for efficient tetracycline degradation. The integration of photo, electro, and Fenton processes synergistically enhances hydroxyl radical (•OH) generation and charge‐carrier separation, ensuring superior removal efficiency. The cathode was synthesized via a Schiff base formation method, which facilitates functionalization of Ti 3 C 2 T x MXene with ferrocene, as confirmed by X‐ray diffraction, X‐ray photoelectron spectroscopy, and UV–visible spectrometry. The Ti 3 C 2 –TiO 2 photoanode was fabricated by electrochemical oxidation of Ti 3 C 2 T x . The photocatalytic properties of anatase TiO 2 , when combined with Ti 3 C 2 T x , create a Schottky junction that significantly improves charge separation, thereby enhancing the photo‐electrocatalytic activity of the system. The hybrid photo‐electro‐Fenton (PEF) system demonstrates a substantial enhancement in tetracycline removal efficiency (∼90%) compared to unmodified Ti 3 C 2 T x ‐based electrodes (∼46%). Furthermore, the Ti 3 C 2 –TiO 2 Schottky photoanode showed enhanced removal efficiency over a commercial P25‐based photoanode for photocatalytic degradation. Through this hybrid PEF oxidation system, the removal efficiencies achieved above 90% in neutral and acidic pH, indicating significant efficacy for the advanced oxidation process. The transformation products formed during the PEF process were analyzed with liquid chromatography coupled with high‐resolution mass spectrometry, showing breakdown of tetracycline and decreasing ecotoxicity with increasing treatment time. Moreover, the MXene‐derived electrode system demonstrates stability and consistent degradation performance over numerous cycles, making it a promising material for environmental remediation applications.

[object Object], [object Object], [object Object] et al.

Applied Physics Letters • 2026

As the BaTiO3 dielectric layer of multi-layer ceramic capacitors becomes thinner, the problem of leakage current degradation arises. In this study, the relationship between the Sn content in Ni–Sn internal electrodes and reliability enhancement is clarified. In addition, based on high-resolution interfacial observations, changes in the work function of the Ni–Sn internal electrode are examined to investigate the mechanism of insulation degradation suppression. Determination of the work function is conducted using both analytical and computational approaches. From these results, the mechanism by which Sn addition to Ni internal electrodes suppresses insulation degradation is discussed.

[object Object], [object Object], [object Object] et al.

Nano-Micro Letters • 2026

Abstract In response to the demanding requirements of next-generation energy storage systems for high-energy density, high-power density, and ultra-long-cycle life, the academic community has continued to focus on coupled devices that combine battery-level energy and capacitor-level power characteristics. Zinc-ion capacitors (ZICs) have become the most promising strategic candidate system for energy storage technology due to their high-energy/power characteristics, excellent intrinsic safety, and significant cost advantages. In this review, the latest research progress of ZICs is reviewed from the perspective of system. Firstly, ZICs are divided into zinc metal anode//capacitive cathode ZICs (ZC-ZICs) and capacitive anode//battery-type cathode ZICs (CB-ZICs) according to the device configuration, and the energy storage mechanisms are analyzed in depth. At the same time, focusing on the two configurations of ZC-ZICs and CB-ZICs and their electrolyte systems, problem-oriented the key puzzles and corresponding solutions are sorted out one by one. Finally, based on the above discussion, this review proposes forward-looking suggestions for material modifications of ZICs, including pulse voltage activation, application of high-entropy materials, and the development of stable and multi-functional electrolytes, aiming to provide scientific guidance for the practical application of high-performance ZICs and promote the in-depth development of high-performance ZICs research.

[object Object], [object Object], [object Object] et al.

Nano-Micro Letters • 2026

Abstract Wearable and deformable electronics are becoming increasingly essential components of modern healthcare and daily life. To power such devices, flexible electrochemical energy storage (FEES) plays a critical role. The practical performance of FEES is dominated by charge and mass transfer at the electrode-electrolyte interface, similar to many rigid battery technologies. However, a unique challenge for FEES is the durability of this interface under deformation. Herein, we present the first comprehensive review of the interface physics, unveiling the crucial role of interface adhesion in the mechanical endurance of FEES. By bridging adhesion physics, material chemistry, and device mechanics, adhesion reinforcement strategies are comprehensively discussed and quantitatively compared, providing multi-scale mechanisms for optimizing FFES interface - from nanoscale bond engineering to microscale surface topology, mechanical interlocking, and macroscale device design. Further, inspired by the synergetic effect of adhesion mechanisms, we propose potential research directions for durable electrode-electrolyte interfaces under dynamic deformation. We also revisit the evaluation of flexibility and electrochemical performance, proposing an application-driven bending index for device assessment. These insights on electrode-electrolyte interface physics of FEES will facilitate the flourishing future of flexible devices.

[object Object], [object Object], [object Object] et al.

Advanced Energy Materials • 2026

ABSTRACT Solid oxide electrochemical cells (SOCs) employ mixed ionic–electronic conducting (MIEC) perovskite electrodes, where electrochemical performance is dictated by the oxygen surface exchange coefficient ( k ) and the concentration of oxygen vacancies (δ). Conventional methods evaluate k and δ separately and under conditions that do not reflect their coupled behavior during operation, offering only a partial picture of the underlying processes. Here we report an in situ methodology that simultaneously resolves k and δ under realistic SOC operating conditions, using a dense bulk electrode integrated with a solid electrolyte. An applied overpotential induces an abrupt drop in the oxygen chemical potential gradient, enabling direct analysis of defect chemistry and surface reaction kinetics. The extracted values are consistent with those obtained from established characterization methods, validating the accuracy of the approach. Beyond fundamental characterization, the platform captures dynamic evolutions in defect chemistry and reaction kinetics, providing mechanistic insights into electrode degradation.

[object Object], [object Object], [object Object] et al.

Research Square • 2026

Abstract The development of high‐performance supercapacitor electrodes relies on materials that combine high electrical conductivity, large accessible surface area, and stable redox behavior. In this study, rGO/MnO₂/ Zeolitic Imidazolate Framework-8 (ZIF-8) composite electrodes were fabricated on nickel foam through a sequential electrophoretic deposition (EPD) technique. Graphene oxide was synthesized via the Tour method, MnO₂ was obtained through a co-precipitation process followed by calcination, and ZIF-8 was subsequently deposited to construct a ternary hybrid structure. Raman spectroscopy confirmed the formation of β-MnO₂ and rGO, with an increased I D /I G ratio (1.81), indicating higher defect density favorable for electrochemical activity. FESEM–EDX analysis revealed a hierarchical architecture composed of rGO nanosheets supporting MnO₂ nanoparticles and ZIF-8 crystals with uniform elemental distribution, confirming successful composite integration. Electrochemical characterization in 0.5 M Na₂SO₄ demonstrated that rGO/MnO₂/ZIF-8 electrode delivered the highest performance compared to pristine MnO₂ (17.19 F g⁻¹) and ZIF-8 (11.83 F g⁻¹), exhibiting a specific capacitance of 42.90 F g⁻¹ at 10 mV s⁻¹ (CV) and 30.74 F g⁻¹ at 0.1 A g⁻¹ (GCD).The b-value analysis suggested a combined capacitive and diffusion-controlled mechanism, while EIS results indicated a markedly reduced charge-transfer resistance (Rct = 180.8 Ω), attributed to the conductive rGO network and the porous ZIF-8 framework. These synergistic effects enhanced electron transport, ion diffusion, and redox activity. Overall, the rGO/MnO₂/ZIF-8 composite demonstrates improved electrochemical performance and structural stability, highlighting its potential as a promising electrode material for next-generation supercapacitors.

[object Object], [object Object], [object Object] et al.

AIChE Journal • 2026

Abstract Understanding the interplay between intrinsic kinetics and transport remains a central challenge in electrocatalysis. Rotating disk electrodes (RDE) are widely used because their transport can be described analytically, but radial concentration gradients complicate analysis of multi‐electron processes. Rotating cylinder electrodes (RCE) provide an improved convective transport profile that better separates transport from kinetics. However, multiphysics simulations show that the use of a single flat counter electrode distorts the electric field in low‐conductivity electrolytes. We present a third‐generation gastight RCE cell (RCE‐3) with two flat counter electrodes symmetrically positioned around the cylinder. This configuration doubles the counter electrode area, increases achievable current density, and improves field symmetry while maintaining well‐defined hydrodynamics. Electrochemical CO 2 reduction experiments demonstrate that asymmetric electric fields bias apparent kinetics in non‐aqueous electrolytes, whereas symmetric counter electrode operation minimizes these distortions, enabling reliable extraction of intrinsic kinetic parameters. The RCE‐3 cell contributes to advancing the mechanistic understanding of non‐aqueous electrocatalytic systems.

[object Object], [object Object], [object Object] et al.

Journal of The Electrochemical Society • 2026

Abstract One major degradation mechanism in Ni-yttria-stabilized-zirconia (Ni/YSZ) fuel electrodes is the migration of Ni away from the fuel electrode-electrolyte interface. This degradation mechanism continues to pose a significant challenge in context of fuel electrode supported cell (FSCs). It significantly impacts both electrochemical performance and electrode lifetime. Ni migration is typically observed when operating at high current densities that lead to high overpotentials. In this work, two fuel electrode supported cells are compared, both with respect to initial electrochemical performance and lifetime. The two cells had similar initial overall resistance when operated in steam electrolysis at -0.75 A/cm 2 , inlet of H 2 O/H 2 :90/10 at 750 °C. Cell 1 initially had low resistance due to physical processes i.e. concentration polarization (R conc ) and high resistance due to electrochemical processes at the Ni/YSZ electrode (R Ni/YSZ ); while Cell 2 was designed to have high concentration polarization (R conc ) and low resistance due to electrochemical processes at the Ni/YSZ electrode. This work shows that it is R Ni/YSZ – not R conc or total resistance - that is the determining resistance contribution for fuel electrode degradation and Ni migration. Furthermore, post-test analysis show presence of impurities and a microstructure indicating a pre-cursor state for Ni migration.

[object Object], [object Object], [object Object] et al.

Small Methods • 2026

ABSTRACT Flexible and wearable triboelectric nanogenerators (TENGs) are considered promising candidates for mechanical energy harvesting and self‐powered sensing, yet simultaneously achieving high output performance together with environmental adaptability remains challenging. In this study, a hydrophobic nanofiber‐reinforced paper‐based TENG (HF‐PTENG) was developed by integrating (3‐aminopropyl)triethoxysilane (APTES)‐modified polyacrylonitrile/aramid nanofiber (PANA) membranes and a flexible conductive paper electrode (FCPE). The HF‐PTENG delivered an open‐circuit voltage of 384.3 V, a short‐circuit current of 15.1 µA, and a transferred charge of 149.5 nC, achieving a maximum instantaneous power destiny of 2.1 mW/cm 2 . Stable electrical output was maintained over 11 000 operation cycles, and efficient biomechanical energy harvesting was demonstrated from finger tapping, wrist bending, and knee motions to power capacitors, commercial LEDs, and sensors. A smart glove integrated with the HF‐PTENG was designed to achieve wireless control of a miniature car via WiFi communication. In addition, a 3×3 TENG sensor array was constructed to visualize planar pressure distribution. Separately, convolutional neural network (CNN) analysis enabled the recognition of six finger‐drawn patterns with an accuracy of 98.32%. This study offers a practical and scalable strategy for constructing high‐performance, flexible TENGs with board potential for applications in wearable electronics, human–machine interfaces, and intelligent motion sensing.

[object Object], [object Object], [object Object] et al.

Energies • 2026

This study presents the electrochemical characterization of a novel, binder-free, plasma-treated aluminum/carbon electrode (“Surge”) using lithium metal half-cells. The low operating potential near 0 V vs. Li/Li+ enables the investigation of the electrode’s charge storage mechanisms and stability limits. We compare its electrochemical behavior in coin cells (CR2032) against two reference configurations: (i) the Surge electrode with a thin copper backer (Surge + Cu-backer) and (ii) a commercial graphite electrode on an aluminum current collector (C-REF). The Surge electrode demonstrated ultra-high initial specific capacities of up to approximately 4500 mAh/g (cycle 1) with Coulombic efficiencies exceeding 85% after the formation cycle. The observed capacity significantly exceeds the theoretical value for Li-Al alloying (993 mAh/g), indicating that lithium plating within the porous carbon scaffold contributes substantially to the total charge storage. However, this high performance was limited to approximately 8 to 9 stable cycles. Post-cycling analysis via scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (SEM/EDX) revealed a dominant failure mechanism: partial dissolution and consumption of the Al current collector leading to material redistribution. Quantitative EDX analysis showed a decrease in Al content from 45 at.% to 12 at.% alongside an increase in oxygen content from 8 at.% to 38 at.%, suggesting extensive Al-oxide formation. Critically, in the absence of a backer, Al-containing material deposited onto the stainless-steel cell components. The Cu backer served to redirect these deposits, improving current collection and modestly extending the short-term durability to approximately 1800 mAh/g at cycle 14 (approximately 75% capacity retention). In contrast, the C-REF control cell reached only approximately 1000 mAh/g (cycle 4) before failing within 5 to 6 cycles, underscoring the inherent instability of bare Al at low potentials. This characterization study establishes the Surge architecture as a successful proof-of-concept for ultra-high capacity charge storage and identifies Al dissolution as the dominant degradation mechanism. Future optimization must focus on stabilizing the Al substrate through protective interphases, alloying, or electrolyte engineering.

[object Object], [object Object], [object Object] et al.

Advanced Healthcare Materials • 2026

ABSTRACT Conductive polymer coatings have been extensively explored as a means of improving the quality of neural signals recorded with chronically implanted electrodes. They offer enhanced biocompatibility along with reduced electrode impedance and are reported to improve signal‐to‐noise ratio and signal amplitude. The mechanisms by which poly(3,4ethylenedioxythiophene) (PEDOT) and its derivatives enhance the quality of neural signals recorded in vivo, however, remain unclear. Here, a computational model of PEDOT:PTS (polythiophenesulfonyl chloride) coated neural recording electrodes is used to understand how the different properties of conductive electrode coatings influence local field potentials recorded in vivo. Impedance, histology and electrophysiology data were obtained from coated and uncoated microelectrodes chronically implanted in the rat basal ganglia and incorporated in the model. Together the simulation and experimental results indicate that improvements in signal quality with PEDOT:PTS coated electrodes are driven by greater neural proximity to the electrode, facilitated by reduced peri‐electrode gliosis. Reductions in thermal noise with decreasing electrode impedance further contributed to a higher signal‐to‐noise ratio for PEDOT:PTS coated electrodes. Finally, the results demonstrate that, provided amplifier input impedance requirements are satisfied, the enhanced recording capability of polymer coated electrodes compared to uncoated electrodes is due primarily to improved biocompatibility rather than reduced electrode impedance.

[object Object], [object Object]

Advanced Engineering Materials • 2026

4‐aminophenol (AMP) and 4‐acetamidophenol (ACP) are significant compounds in the pharmaceutical, dye, and cosmetic industries and analytical fields, with the uncontrolled release caused serious of environmental and health risks. So, necessitating their sensitive and selective detection through voltammetric studies. To achieve this, Chromium Titanium Yttrium oxide nanocomposites (CrTiYONC) were synthesised via a simple combustion method using chromium(III) nitrate, titanium(III) nitrate, and yttrium(III) nitrate as precursors, with glycine serving as the fuel. The combustion process is carried out at 750°C, producing phase‐pure nanostructures. These nanocomposites are then employed to modify the electrode surface, where an arginine‐functionalized polymeric film was electrochemically deposited onto the carbon paste electrode through the cyclic voltammetric technique. The modified electrode displays an enhanced active surface area, better conductivity, and augmented transfer of electron–proton owing to the synergistic effect of CrTiYO NC structures and the polymeric film. The electrochemical studies, like electrochemical impedance spectroscopy, cyclic voltammetry, linear sweep voltammetry, and differential pulse voltammetry, disclose that the AM‐CrTiYO‐CPE follows a diffusion‐controlled electrochemical redox mechanism with optimised conditions of 0.1 M BS solution at pH 7.2 in 0.1 V s −1 scan rate. The developed AM‐CrTiYO‐CPE validates remarkable electrocatalytic activity toward the detection of AMP and ACP, achieving low detection limits in a wide linear range. The fabricated electrode further displays an excellent stability, selectivity, sensitivity, reproducibility, and repeatability, with kinetics and availability of the electroactive site. The selective nature of the AM‐CrTiYO‐CPE electrode toward the quantification of AMP and ACP highlights its significant potential for applications in pharmaceutical formulation analysis, enironmental monitoring, drug delivery systems, quality control, and clinical diagnostics.

[object Object], [object Object], [object Object] et al.

Journal of The Electrochemical Society • 2026

To suppress dendrite formation, MoC-Mo 2 C electrode was selected as the working electrode for extracting Cr from LiCl-KCl molten salt. The MoC-Mo 2 C electrode was prepared by anodization at 0.005 A cm −2 for 2 h in Li 2 CO 3 -K 2 CO 3 molten salt, which displayed a porous structure. Then, the electrochemical mechanism of Cr(III) on this electrode was studied by cyclic voltammetry, square wave voltammetry, and current reversal chronopotentiometry, confirming that reduction of Cr(III)/Cr(II) and Cr(II)/Cr(0) was reversible and diffusion-controlled. The diffusion coefficient of Cr(III) was determined to be on the order of 10 –5 cm 2 s −1 in the temperature range of 713–833 K, and the diffusion activation energy of Cr(III) was also estimated. Meanwhile, the electrode kinetics of Cr(II)/Cr(0) was measured by Tafel and LP techniques. The exchange current density( j 0 ) measured by the two methods were very close, and j 0 increased with increasing the temperature. Moreover, the nucleation mechanism of Cr measured by CA conformed to instantaneous nucleation on MoC-Mo 2 C electrode. Potentiostatic electrodeposition was performed on Mo and MoC-Mo 2 C electrodes, respectively. The obtained products characterized by scanning electron microscopy-energy-dispersive microscopy and X-ray diffraction indicated that the formed Cr exhibited a sparse dendritic morphology on Mo electrode, while a dense spherical morphology on MoC-Mo 2 C electrode.

[object Object], [object Object], [object Object] et al.

Research Square • 2026

Abstract This study constructed a composite system using Shewanella oneidensis MR-1 and iron oxide-loaded biochar (FeO/C) to investigate the simultaneous removal of Cr(VI) and chlorpyrifos (CPF). The system achieved removal efficiencies of 73.47% for Cr(VI) and 70.12% for CPF within 144 h, fitting a pseudo-first-order kinetic model (k Cr k CPF ). SEM confirmed FeO/C as an effective colonization substrate facilitating bacterial adaptation. Oxidative stress analysis revealed an initial surge in reactive oxygen species that activated antioxidant enzymes (e.g., SOD, CAT), culminating in glutathione depletion and elevated malondialdehyde by 144 h. Proteomic profiling indicated that the upregulation of thioredoxin (trxC) and iron storage proteins (bfr) was crucial for maintaining redox balance and electron transfer. Furthermore, enriched metabolic pathways supported the energy demands for detoxification, elucidating the adaptive molecular mechanisms of the MR-1@FeO/C system under composite pollution.

Environmental science and pollution research international • 2025

Hydrogen is a promising alternative to meet the world's energy demand in the future because of its energetic characteristics. Microbial electrolysis cell (MEC) produces hydrogen from organic matter using exoelectrogenic bacteria. Shewanella oneidensis stands out for having the capacity to produce hydrogen using different electron transfer mechanisms. The present research aims to evaluate the hydrogen production efficiency in a MEC inoculated with a pure culture of S. oneidensis in different operational conditions. Since the use of a catalyst accounts for most of the MEC cost, no catalyst was used for anode or cathode. Experiments were performed in semi-continuous and batch mode using different electrodes, voltages applied, and medium in aerobic and anaerobic conditions. The highest hydrogen production rate (HPR) was 0.107 m 3 of H 2 /m 3 day obtained in a semi-continuous experiment using graphite plates and stainless steel electrodes. In batch experiments, a HPR occurred at 0.7 V, with a value of 0.048 m 3 of H 2 /m 3 day versus 0.037 m 3 of H 2 /m 3 day with 0.9 V. HPR was higher with carbon felt electrode (0.056 m 3 of H 2 /m 3 day). However, current density dropped after 38 h, with carbon felt electrodes, and did not recover. Results of the present research showed that the MEC using a pure culture of S. oneidensis can be considered an alternative for hydrogen production without using a catalyst. Also, S. oneidensis produced hydrogen in both anaerobic and aerobic conditions with low methane production. Optimization can be proposed to improve hydrogen production based on the operational conditions tested in these experiments.

[object Object], [object Object], [object Object] et al.

Environmental science & technology • 2025

Early detection of pollutants in water discharge is an integral part of environmental monitoring. Electroactive biofilm (EAB)-enabled, microbial fuel cell (MFC)-based biosensors facilitate self-powered online pollutant detection. However, as EABs are highly dynamic, naturally formed EABs as sensing and transducing elements limit the performance of MFC-based biosensors. Here, we report a fast-response and sensitive MFC-based biosensor enabled by enhancing Shewanella oneidensis biofilms on the electrode using an optogenetic approach. We incorporated a near-infrared (NIR) light-responsive synthetic bis(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) module into S. oneidensis to promote biofilm formation on the anode under NIR light. The biosensors with enhanced EABs exhibited a rapid and sensitive response to Cr(VI), reducing the sensing time from approximately 30 min to just 3 min. This improved sensing performance was maintained over three sensing cycles, even with fluctuating Cr(VI) concentrations. Based on the analyses of the electrode biofilms and extracellular polymeric substance matrices, different Cr(VI) response mechanisms for the normal and enhanced EABs were proposed; enhanced EAB's massive dispersal by Cr(VI) was the cause of the improved response of the biosensors. Such improved response still held in the natural water matrix. This proof-of-concept study provides valuable insights into controlling electrode biofilm dynamics for the rapid and robust early detection of pollutants using MFC-based biosensors.

Archives of microbiology • 2025

Dissimilatory metal-reducing bacteria (DMRB) have been considered very important contributors in developing and operating microbial fuel cells that represent one promising technology for waste treatment and sustainable energy generation. In keeping with this spirit, this review paper will scrutinise the elementary mechanisms whereby the unique metabolic processes of DMRB enable their role in facilitating the extracellular transmission of electrons to the anode from organic substrates. Important species like Shewanella and Geobacter are referred to because of their contributions toward improving the stability and efficiency of MFCs. The paper also discusses the benefits of using DMRB, such as their potential in bioremediation and increased electron transfer efficiency. Difficulties examined include preserving microbial stability, competing with other species, and improving operating conditions. The recent developments in materials science, genetic engineering, and integration with other renewable technologies are discussed to demonstrate the potential for future breakthroughs. The last section of this paper discusses the wider implications of DMRB in developing MFC technology for energy and environmental applications.

Journal of bioscience and bioengineering • 2025

Shewanella oneidensis MR-1 possesses an extracellular electron transfer (EET) pathway that enables bidirectional electron exchange with electrodes, making it a promising host for electro-fermentation (EF). However, the intracellular redox reactions driven by MR-1 during electron uptake from the electrodes remain poorly characterized. This study investigated the metabolic fate of pyruvate, a key fermentation intermediate, during inward electron transfer from a low-potential cathode. To examine this, an MR-1 derivative lacking formate dehydrogenase (ΔFDH), which is unable to utilize formate as an electron donor for pyruvate reduction, was incubated under open-circuit (OC) conditions and closed-circuit (CC) conditions with an electrode poised at -0.36 V (vs. the standard hydrogen electrode). A comparative analysis of pyruvate-derived metabolites under these conditions revealed that ΔFDH produced significantly higher amounts of d-lactate under CC conditions, indicating cathode-derived electron utilization for pyruvate reduction to d-lactate. Further gene knockout experiments in the ΔFDH background showed that two d-lactate dehydrogenases (D-LDHs) in MR-1, Dld (a quinone-dependent inner membrane D-LDH) and LdhA (an NADH-dependent D-LDH), contributed almost equally to cathode-dependent d-lactate production. These results indicate that electron transfer from electrodes to pyruvate in MR-1 cells involves both inner membrane quinone-mediated and NADH-mediated redox reactions, highlighting the potential applicability of MR-1 in diverse EF processes.

Analytical chemistry • 2025

Bioelectrochemical sensors (BES) are promising to specifically detect nitrate or nitrite but never realize simultaneous detection in a single system. In this study, a novel biosensor using self-assembled hydrogel bioelectrodes with reduced graphene oxide (rGO) and genetically engineered electroactive Shewanella species was designed for the simultaneous detection of nitrate and nitrite. The highly conductive rGO rendered a drastically improved reverse electron transfer from the electrode to Shewanella , which achieved a sensitive and quantitative response to nitrite/nitrate. Meanwhile, the genetically engineered Shewanella enabled efficient differentiation of nitrate and nitrite detection in a single system (a sensitivity of 883.48 μA mM -1 cm -2 to nitrate with a limit of detection of 0.92 μM and a sensitivity of 888.48 μA mM -1 cm -2 to nitrite with a limit of detection of 0.72 μM). The whole-cell biohydrogel based BES also showed excellent anti-interference and long-term storability for plug-and-play application. Based on these properties, this work demonstrated the power of genetically engineered electroactive bacteria in rGO biohydrogel for dual-analyte detection and also provided a new strategy for developing high-performance whole-cell BES for practical environmental monitoring.

Bioelectrochemistry (Amsterdam, Netherlands) • 2025

The nanowires of the model electroactive bacterium Shewanella oneidensis have been the subject of numerous studies to elucidate their structure and function. These previous reports have elegantly utilised advanced microscopic techniques to investigate nanowires formed in response to oxygen limitation. However, the detailed structure of nanowires formed on electrodes during extracellular electron transfer has not been reported and it is imperative to determine whether they possess the same vesicular structure that has been reported in the absence of extracellular electron transfer. Using an acetone hexamethyldisilazane dehydration method to preserve soft biological materials, we employed the relatively uncomplicated technique of secondary electron field emission-scanning electron microscopy to visualise the vesicular nanowire structure while attached to an electrode from an operating bioelectrochemical system. Early-stage nanowires appear to consist of intact chains of outer-membrane vesicles forming connections with the electrode surface and with neighbouring cells. Relying on secondary electrons from the inherently conductive carbon felt electrode, sputter coating could be avoided and the delicate structure of the vesicles was preserved with increased detail. The findings inform the fundamental understanding of nanowires during electron transfer and the simple protocol will allow their examination on a variety of existing and emerging electrode materials.

ACS sensors • 2025

As a water-soluble vitamin, Vitamin B2 (VB2) is crucial for the health of living organisms. Therefore, developing sensitive and selective methods for detecting VB2 is essential for the quality control of food and pharmaceuticals as well as for clinical diagnosis. In this study, a cell-embedded living graphene hydrogel needle was prepared under ambient atmospheric conditions, where the electroactive bacteria Shewanella oneidensis MR-1 was used to induce the reduction of graphene oxide (GO) to graphene hydrogel under the confinement effect with a glass capillary tube. By using this living graphene hydrogel needle, an electrochemical biosensor for the detection of VB2 in microdroplet samples was developed. By taking advantage of a microscale graphene needle and electroactive S. oneidensis MR-1, this biosensor exhibited high sensitivity (LOD = 8.42 nM), excellent selectivity, and good anti-interference ability for amperometric detection of VB2 in a microdroplet (1 μL, the record-low sample volume). This work provided a reliable tool for trace detection of VB2 with minimized sample requirement, offering a sensitive and practical approach for food safety inspection and disease diagnosis with precious or limited samples.