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The coexistence of oxygen and/or nitrate at anode usually affects the biofilm activities of traditional anaerobic anode, thereby deteriorating wastewater treatment performance of microbial fuel cells (MFCs). Improving the aerotolerant responses of anode biofilms is a challenge for field application. In this study, we report that using the electroactive nitrifying/denitrifying inoculum and air-cathode expansion could fabricate the aerotolerant anode biofilms (AAB) under affordable nitrate stress (90 ± 5 mg/L). The highest average removal efficiencies were 99% for chemical oxygen demand (COD), NH4+-N and total nitrogen. The highest average current output of 0.69 mA and power density of 290 mW/m2 were obtained. The average current was confirmed to be reduced 10%-78% but the power density remained almost stable except the quart-air-cathodes MFC by increasing dissolved oxygen concentration with expansion of the air-cathode area. The higher oxygen concentration also contributed to oxidation of ammonium through electroactive autotrophic nitrification. The facultative anaerobic bacteria including Thauera, Microsillaceae, Shinella, Blastocatellaceae, Rhodobacter, Comamonadaceae, Caldilineaceae were enriched, which forms the AAB to remove nitrogen and produce current. Therefore, an easy-to-use method to fabricate AAB is evaluated to realize practical applications of MFCs in wastewater treatment.

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gLiving materials can achieve unprecedented function by combining synthetic materials with the wide range of cellular functions. Of interest are situations where the critical properties of individual abiotic and biotic elements improve via their combination. For example, integrating electroactive bacteria into conjugated polyelectrolyte (CPE) hydrogels increases biocurrent production. One observes more efficient electrical charge transport within the CPE matrix in the presence of Shewanella oneidensis MR-1 and more current per cell is extracted, compared to traditional biofilms. Here, the origin of these synergistic effects are examined. Transcriptomics reveals that genes in S. oneidensis MR-1 related to bacteriophages and energy metabolism are upregulated in the composite material. Fluorescent staining and rheological measurements before and after enzymatic treatment identified the importance of extracellular biomaterials in increasing matrix cohesion. The synergy between CPE and S. oneidensis MR-1 thus arises from initially unanticipated changes in matrix composition and bacteria adaption within the synthetic environment.

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Heart failure (HF) represents a cardiovascular disease that significantly threatens global well-being and quality of life. Electroactive nanomaterials, characterized by their distinctive physical and chemical properties, emerge as promising candidates for HF prevention and management. This review comprehensively examines electroactive nanomaterials and their applications in HF intervention. It presents the definition, classification, and intrinsic characteristics of conductive, piezoelectric, and triboelectric nanomaterials, emphasizing their mechanical robustness, electrical conductivity, and piezoelectric coefficients. The review elucidates their applications and mechanisms: 1) early detection and diagnosis, employing nanomaterial-based sensors for real-time cardiac health monitoring; 2) cardiac tissue repair and regeneration, providing mechanical, chemical, and electrical stimuli for tissue restoration; 3) localized administration of bioactive biomolecules, genes, or pharmacotherapeutic agents, using nanomaterials as advanced drug delivery systems; and 4) electrical stimulation therapies, leveraging their properties for innovative pacemaker and neurostimulation technologies. Challenges in clinical translation, such as biocompatibility, stability, and scalability, are discussed, along with future prospects and potential innovations, including multifunctional and stimuli-responsive nanomaterials for precise HF therapies. This review encapsulates current research and future directions concerning the use of electroactive nanomaterials in HF prevention and management, highlighting their potential to innovating in cardiovascular medicine.

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The growing concern over low-frequency noise pollution resulting from global industrialization has posed substantial challenges in noise attenuation. However, conventional acoustic metamaterials, with fixed geometries, offer limited flexibility in the frequency range adjustment once constructed. This research unveiled the promising potential of ionic electroactive polymers, particularly ionic polymer-metal composites (IPMCs), as a superior candidate to design tunable acoustic metamaterial due to its bidirectional energy conversion capabilities. The previously perceived limitations of the IPMC, including slow reaction and high energy expenditure, owning to its inherent sluggish intermediary ionic mass transport process, were astutely leveraged to expedite the attenuation of low-frequency sound energy. Both our experimental and simulation results elucidated that the IPMC can generate voltage potentials in response to acoustic pressure at frequencies significantly higher than those previously established. In addition, the peak absorption frequency can be effectively shifted by up to 45.7% with the application of a 4 V voltage. By further integration with a microperforated panel (MPP) structure, the developed metamaterial absorbers can achieve complete sound absorption, which was continuously tunable under minimal voltage stimulation across a wide frequency spectrum. In addition, a microslit structure IPMC metamaterial absorber was designed to realize modulation of the perforation rate, and the absorption peak can be shifted by up to 79.2%. These findings signify a pioneering application of ionic intelligent materials and may pave the way for further innovations of tunable low-frequency acoustic structures, ultimately advancing the pragmatic deployment of both soft intelligent materials and acoustic metamaterials.

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Electrochromic smart windows (ESWs) are an effective energy-saving technology for near-zero energy buildings. They consume electric energy unidirectionally during a round-trip coloring-bleaching process, with the energy involved in the bleaching process being wasted. It is highly desirable to reuse this wasted electric energy directly and/or transfer it into other energy storage equipment, further enhancing the overall efficiency of electric energy usage. Herein, a zinc anode-based ESW (ESW-PZ) is reported that not only has fascinating visible-near-infrared (VIS-NIR) dual-band electrochromic performance (a high optical contrast of 63%) but also showcases good energy storage characteristics (a wide voltage window of 2.6 V and a high energy density of 127.5 µWh cm-2). The buildings utilizing ESW-PZ to modulate indoor environments demonstrated an average annual energy saving of 366 MJ m-2 based on energy simulations, which is about 16% of the total energy consumption. Impressively, a high utilization efficiency of 90% (855 mWh m-2) of the wasted electric energy is realized through an ingenious circuit-switching strategy, which can be reused to power small household appliances.

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To fabricate electroactive fibrous membranes and provide simulated bioelectric micro-environment for bone regeneration mimicking nature periosteum, a series of electroactive polyurethanes (PUAT) were synthesized using amino-capped aniline trimers (AT) and lysine derivatives as chain extenders. These PUAT were fabricated into fibrous membranes as guided bone tissue regeneration membranes (GBRMs) via electrospinning. The ultraviolet-visible (UV-vis) absorption spectroscopy and cyclic voltammetry (CV) of PUAT copolymers showed that the electroactive PUAT fibrous membranes had good electroactivity. Besides, the introduction of AT significantly improved the hydrophobicity and thermal stability of PUAT fibrous membranes and decreased the degradation rate of PUAT fibers in vitro. With the increasing content of AT incorporated into copolymers, the tensile strength and Young's modulus of PUAT fibrous membranes increased from 4 MPa (PUAT0) to 15 MPa (PUAT10) and from 2.1 MPa (PUAT0) to 18 MPa (PUAT10), respectively. The cell morphology and proliferation of rat mesenchymal stem cells (rMSCs) on PUAT fibers indicated that the incorporation of AT enhanced the cell attachment and proliferation. Moreover, the expression levels of OCN, CD31, and VEGF secreted by rMSCs on PUAT fibers increased with the increasing content of AT. In conclusion, an electroactive polyurethane fibrous membrane mimicking natural periosteum was prepared via electrospinning and showed good potential application in guiding bone tissue regeneration.

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Subcellularly amperometric analysis in situ is crucial for understanding intracellular redox biochemistry and subcellular heterogeneity. Unfortunately, the ultra-small size and complex microenvironment inside the cell pose a great challenge to achieve this goal. To address the challenge, a minimized living microbial sensor has been fabricated in this work for amperometric analysis. Here, by fabricating the dimidiate microelectrode as the working electrode, while fitting a living electroactive bacterium (EAB) as the transducer, outward extracellular electron transfer (EET) of the sensory EAB is correlated with the concentration of lactic acid, which is electrochemically recorded and thus displays an electrical signal output for detection. In specific, the S. oneidensis modified dimidiate microelectrode (S.O.@GNE-NPE) acts as an integrated electroanalytical device to generate the electrical signal in situ. The established microcircuit provides unprecedented precision and sensitivity, contributing to subcellular amperometric measurement. The microbial sensor shows a linear response in the concentration range of 0-60 mM, with a limit of detection (LOD) at 0.3 mM. The microsensor also demonstrates good selectivity against interferences. Additionally, intracellular analysis of lactic acid provides direct evidence of enhanced lactic metabolism in cancer cells as a result of "Warburg Effect". This work shows an example of nano-, bio- and electric technologies that have been integrated on the EAB-modified dimidiate microelectrode, and achieves intracellular biosensing application through such integration. It may give a new strategy on the combination of micro/nanotechnologies with sensory EAB for the necessary development of bioelectronic devices.

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The functionality of electroactive biofilms (EABs) is profoundly influenced by the proteomic dynamics within microbial communities, particularly through the participation of proteins in electron transfer. This study explored the impact of electrode surface orientation, measured by varying oblique angles, on the performance of EABs in bioelectrochemical systems (BES). Utilizing quantitative proteomics, results indicated that a slightly oblique angle (45°) optimized the spatial arrangement of microbial cells, enhancing electron transport efficiency compared to other angles tested. Specifically, the 45° orientation resulted in a 2.36-fold increase in the abundance of c-type cytochromes compared to the 90°. Additionally, Geobacter, showed a relative abundance of 83.25 % at 45°, correlating with a peak current density of 1.87 ± 0.04 A/m2. These microbial and proteomic adaptations highlighted the intricate balance between microbial behavior and the physical environment, which could be tuned to optimize operations. The findings provided new insights into the design and enhancement of BES.

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Anaerobic digestion provides a solution to the inefficient use of carbon resources caused by improper disposal of corn stover-based ethanol stillage (CES). In this regard, we developed a single-chamber anaerobic digestion integrated microbial electrolysis cells system (AD-MEC) to convert CES into biogas while simultaneously upgrading biogas in-situ by employing voltages ranging from 0 to 2.5 V. Our results demonstrated that applying 1.0 V increased the CH4 yield by 55 % and upgraded the CH4 content in-situ to 82 %. This voltage also promoted the well-formed biofilm on the electrodes, resulting in a 20-fold increase in current. However, inhibition was observed at high voltages (1.5-2.5 V), suppressing syntrophic organic acid-oxidizing bacteria (SOB). The dissociation between SOB and methanogens led to accumulation of propionic and butyric acid, which, in turn, inhibited methanogens. The degradation of CES was accelerated by unclassified_o_norank_c_Desulfuromonadia on the anode, likely leading to an increase in mixotrophic methanogenesis due to the synergistic interaction among Aminobacterium, Sedimentibacter, and Methanosarcina. Furthermore, the enrichment of electroactive bacteria (EB) such as Enterococcus and Desulfomicrobium likely facilitates direct interspecies electron transfer to Methanobacterium, thereby promoting the conversion of CO2 to CH4 through hydrogenotrophic methanogenesis. Rather than initially stimulating the EB in the bulk solution to accelerate the start-up process of AD, our study revealed that applying mild voltage up to 1.0 V tended to mitigate the negative impact on the original microorganisms, as it gradually enriched EB on the electrode, thereby enhancing biogas production.

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With the rapid development of modern industry, it is urgently needed to measure the biotoxicity of complex chemicals. Microbial electrochemical biotoxicity sensors are an attractive technology; however, their application is usually limited by their stability and reusability after measurements. Here, we improve their performance by encapsulating the electroactive biofilm with polydopamine (PDA), and we evaluate the improvement by different concentrations of heavy metal ions (Cu2+, Ag+, and Fe3+) in terms of inhibition ratio (IR) and durability. Results indicate that the PDA-encapsulated sensor exhibits a more significant detection concentration than the control group, with a 3-fold increase for Cu2+ and a 1.5-fold increase for Ag+. Moreover, it achieves 15 more continuous toxicity tests than the control group, maintaining high electrochemical activity even after continuous toxicity impacts. Images from a confocal laser scanning microscope reveal that the PDA encapsulation protects the activity of the electroactive biofilm. The study, thus, demonstrates that PDA encapsulation is efficacious in improving the performance of microbial electrochemical biotoxicity sensors, which can extend its application to more complex media.

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Electroactive microorganisms (EAMs) play a vital role in biogeochemical cycles by facilitating extracellular electron transfer. They demonstrate remarkable adaptability to river sediments that are characterized by pollution and poor water quality, significantly contributing to the sustainability of river ecosystems. However, the distribution and diversity of EAMs remain poorly understood. In this study, 16S rRNA gene high-throughput sequencing and real-time fluorescence quantitative PCR were used to assess EAMs in 160 samples collected from eight rivers within the Pearl River Delta of Southern China. The results indicated that specialized EAMs communities in polluted sediments exhibited variations in response to water quality and sediment depth. Compared to clean sediment, polluted sediments showed a 4.5% increase in the relative abundances of EAMs communities (59 genera), with 45- and 17-times higher abundances of Geobacter and cable bacteria. Additionally, the abundance of cable bacteria decreased with increasing sediment depth in polluted sediments, while the abundance of L. varians GY32 exhibited an opposite trend. Finally, the abundances of Geobacter, cable bacteria, and L. varians GY32 were positively correlated with the abundance of filamentous microorganisms (FMs) across all samples, with stronger interactions in polluted sediments. These findings suggest that EAMs demonstrate heightened sensitivity to polluted environments, particularly at the genus (species) level, and exhibit strong adaptability to conditions characterized by high levels of acid volatile sulfide, low dissolved oxygen, and elevated nitrate nitrogen. Therefore, environmental factors could be manipulated to optimize the growth and efficiency of EAMs for environmental engineering and natural restoration applications.

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Electrobioremediation is one of the most innovative disciplines for treating organic pollutants and it is based on the ability of electroactive bacteria to exchange electrons with electroconductive materials. Electroactive biofilters have been demonstrated to be efficient for treating urban wastewater with a low footprint; however, their application can be expanded for treating industrial wastewater containing significant concentrations (2.4 %vol) of commercial surfactants (containing lauryl sulfate, lauryl ether sulfate, cocamydopropyl betaine, and dodecylbenzene sulfonate, among others). Our electroactive biofilter outperformed a conventional inert biofilter made of gravel for all tested conditions, reaching removal rates as high as 4.5 kg COD/m3bed·day and withstood Organic Loading Rates as high as 9 Kg COD/m3·d without significantly affecting removal efficiency. The biomass accumulation reduced available bed volume in the electroactive biofilter just by 39 %, while the gravel biofilter decreased by 80 %. Regarding microbial communities, anaerobic and electroactive bacteria represented a substantial proportion of the total population in the electroactive biofilter. Pseudomonas was the dominant genus, while Cupriavidus, Shewanella, Citrobacter, Desulfovibrio, and Arcobacter were potential electroactive strains found in relevant proportions. The microbial community's composition might be the key to understanding how high removal rates can coexist with limited biomass production, making electroactive biofilters a promising strategy to overcome classical biofilter limitations.

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The synthesis of diradical organic compounds has garnered significant attention due to their thermally accessible spin inversion and optoelectronic properties. Yet, preparing such stable structures with high open-shell behavior remains challenging. Herein, we report the synthesis and properties of four π-extended, fused fluorene derivatives with high diradical character, taking advantage of a molecular design where the closed-shell does not include any Clar sextet, comparatively to a maximum of 5 in the corresponding open-shell state. This led to an unusual open-shell triplet ground state with an outstanding singlet-triplet energy difference (ΔEST) of ca. 19 kcal/mol, one of the highest values reported to date for an all-carbon conjugated scaffold. Incorporation of dithiafulvene units at each end of the molecule (at the five-membered rings) furnishes extended tetrathiafulvalenes (TTFs) undergoing reversible oxidations to the radical cation and diradical dication. The various pro-aromatic structures presented herein show highly localized spin density and a limited conjugation due to the confined π-electrons in the aromatic cycles, as supported by 1H NMR, UV-visible, EPR spectroscopy and DFT calculations.

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The diagnosis of diabetes mellitus (DM) affecting 537 million adults worldwide relies on invasive and costly enzymatic methods that have limited stability. Electroactive polypyrrole (PPy)-based molecularly imprinted polymer nanoparticles (eMIPs) have been developed that rival the affinity of enzymes whilst being low-cost, highly robust, and facile to produce. By drop-casting eMIPs onto low-cost disposable screen-printed electrodes (SPEs), sensors have been manufactured that can electrochemically detect glucose in a wide dynamic range (1 µm-10 mm) with a limit of detection (LOD) of 26 nm. The eMIPs sensors exhibit no cross reactivity to similar compounds and negligible glucose binding to non-imprinted polymeric nanoparticles (eNIPs). Measurements of serum samples of diabetic patients demonstrate excellent correlation (>0.93) between these eMIPs sensor and the current gold standard Roche blood analyzer test. Finally, the eMIPs sensors are highly durable and reproducible (storage >12 months), showcasing excellent robustness and thermal and chemical stability. Proof-of-application is provided via measuring glucose using these eMIPs sensor in a two-electrode configuration in spiked artificial interstitial fluid (AISF), highlighting its potential for non-invasive wearable monitoring. Due to the versatility of the eMIPs that can be adapted to virtually any target, this platform technology holds high promise for sustainable healthcare applications via providing rapid detection, low-cost, and inherent robustness.

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Electrochemical sensing (ES) is crucial for improving data acquisition in wastewater treatment, but obtaining the signal for a low electroactive analyte is challenging. Here, we propose an electrochemical acid-base transport limitation (eABTL) principle for inertness-based sensing, offering a new insight into generating ES signals from an interfacial transport process rather than electron transfer. This principle enables potential ES application for various weak acids and bases (WABs) without reactions themselves. We established an eABTLP method for detecting orthophosphate in solutions as a proof of concept, demonstrating commendable accuracy and precision, and a wide detection range from 10 µM to over 300 mM. Endogenous interferences were identified using 23 weak acids, indicating no significant endogenous interfering factors in typical wastewaters. Of them, volatile fatty acids are the main interference, but their effect can be eliminated by adjusting pH above 6.0. Exogenous factors like anions, cations, ion strength, temperature, organic load, and dissolved oxygen were examined, and most of their effects can be ignored by maintaining consistent analytical procedures between calibration curve and sample. Furthermore, measurement of wastewater samples confirmed the applicability toward domestic wastewater and demonstrated its wide applicability when combined with digestion pretreatment. Given the merits of inertness-based sensing, the eABTL-based methods have the potential to be a crucial part of ES techniques for environmental and industrial monitoring.

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Studies have used anaerobic-digester sludge and/or effluent as inocula for bioelectrochemical systems (BESs), such as microbial fuel cells (MFCs), for power generation, while limited studies have isolated and characterized electrochemically active bacteria (EAB) that inhabit anaerobic digesters. In the present work, single-chamber MFCs were operated using the anaerobic-digester effluent as the sole source of organics and microbes, and attempts were made to isolate EAB from anode biofilms in MFCs by repeated anaerobic cultivations on agar plates. Red colonies were selected from those grown on the agar plates, resulting in the isolation of three phylogenetically diverse strains affiliated with the phyla Bacillota, Campylobacterota and Deferribacterota. All these strains are capable of current generation in pure-culture BESs, while they exhibit different electrochemical properties as assessed by cyclic voltammetry. The analyses of their cell-free extracts show that cytochromes are abundantly present in their cells, suggesting their involvement in current generation. The results suggest that anaerobic digesters harbor diverse EAB, and it would be of interest to examine their ecological niches in anaerobic digestion.

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The present work demonstrates the manufacturing process of a pneumatic bellow actuator with an embedded sensor, utilizing a novel manufacturing approach through the complete use of additive manufacturing techniques, such as direct ink writing (DIW) and traditional fused deposition modeling (FDM) methods. This study is innovative in its integration of a dielectric electroactive polymer (DEAP) structure with sensing electrodes made of conductive carbon grease (CCG), showcasing a unique application of a 3D-printed DEAP with CCG electrodes for combined DEAP sensing and pneumatic actuation. Initial experiments, supported by computational simulations, evaluated the distinct functionality of the DEAP sensor by itself under various pressure conditions. The findings revealed a significant change in capacitance with applied pressure, validating the sensor's performance. After sensor validation, an additive manufacturing process for embedding the DEAP structure into a soft pneumatic actuator was created, exhibiting the system's capability for dual sensing and actuation, as the embedded sensor effectively responded to applied actuation pressure. This dual functionality represents an advancement in soft actuators, especially in applications that require integrated and responsive actuation and sensing capabilities. This work also represents a preliminary step in the development of a 3D-printed dual-modality actuator (pneumatic and electrically activated DEAP) with embedded sensing.

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Crafting rational heterojunctions with nanostructured materials is instrumental in fostering effective interfacial charge separation and transport for optoelectronics. Layered halide perovskites (LHPs) that form heterojunctions between organic spacer molecules and inorganic metal halide layers exhibit tunable photophysics owing to their customizable band alignment. However, controlling photogenerated carrier dynamics by strategically designing layered perovskite heterojunctions remains largely unexplored. We combine a data-driven approach with time-domain density functional theory (TD-DFT) and non-adiabatic molecular dynamics (NAMD) to screen and select electronically active spacer dications (A') that introduce a type-II heterojunction in the lead iodide-based Dion-Jacobson phase LHPs. The composition-structure-electronic property correlations reveal that the number of nitrogens in aromatic heterocycles is the key factor in designing electron-accepting spacers in these perovskites. The detailed atomistic simulations validate the design strategy further by modeling (A')PbI4 perovskites, which incorporate three different screened electroactive A' spacers. The computed excited charge carrier dynamics illustrate the phonon-mediated ultrafast interfacial electron transfer from the inorganic conduction band edge to the lower-lying unoccupied orbitals of spacers, exhibiting photoluminescence quenching in these (A')PbI4 perovskites. The spatially separated electrons and holes at the type-II heterojunction interface prolong the excited charge carrier lifetime, boosting the carrier transport and exciton dynamics. Our work illustrates a robust in silico approach for designing LHPs with exciting optoelectronic properties originating from their fine-tuned heterojunctions.

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The detection of small molecules beyond glucose remains an ongoing challenge in the field of biomolecular sensing owing to their small size, diverse structures, and lack of alternative non-enzymatic sensing methods. Here, we present a new reagentless electrochemical approach for small molecule detection that involves directed movement of electroactive analytes through a self-assembled monolayer to an electrode surface. Using this method, we demonstrate detection of several physiologically relevant small molecules as well as the capacity for the system to operate in several biological fluids. We anticipate that this mechanism will further improve our capacity for small molecule measurement and provide a new generalizable monolayer-based technique for electrochemical assessment of various electroactive analytes.

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