Nanobubbles alleviate iron-mediated cell death in algae-bacteria symbiotic systems under sulfamethoxazole stress: Insights into electron transfer and ferrikinetics.

FRET-PET regulated semiconducting polymer dots for ultrasensitive and portable ratiometric detection of benzoyl peroxide.

At-home monitoring of key blood indicators, including cholesterol and glucose, is vital for point-of-care chronic condition management. In this work, portable kits based on L-arginine modified Cu-CuFe2O4 nanoparticles (Cu-CuFe2O4@L-Arg NPs) were fabricated for colorimetric determination of glucose and cholesterol in human serum. Cu-CuFe2O4@L-Arg NPs with superior peroxidase-like activities were synthesized via a straightforward hydrothermal approach. The accelerated electron transfer process of Cu0 and its role as an electron donor contributed to excellent catalytic activity of Cu-CuFe2O4@L-Arg toward 3,3',5,5'-tetramethylbenzidine (TMB). Portable kits include glucose oxidase or cholesterol oxidase, phosphate buffer solution (PBS) pH 7.0, Cu-CuFe2O4@L-Arg, PBS pH 4.0 and TMB. Among the enzyme-like reactions, Cu-CuFe2O4@L-Arg catalyzes the conversion of H2O2 into hydroxyl radicals (•OH), which subsequently oxidize the TMB substrate to yield a blue-colored product. The signal intensities of the blue products were proportional to H2O2, which was produced in the cholesterol or glucose systems. This method achieves linear detection of free cholesterol from 5 µM to 1.2 mM, exhibiting a low LOD of 1 µM, and was validated by obtaining recoveries of 97-103.5% for total cholesterol in human serum analyses. The method enabled the linear quantification of glucose from 50 to 1500 µM with a limit of detection (LOD) of 5 µM, and recoveries in human serum ranged from 96% to 102.8%. The portable kits, characterized by low cost, visual readout, high specificity, and long-term stability, demonstrate considerable potential for self-monitoring devices for key clinical biomarkers.

Enantioselective recognition is vital for numerous chemical and biological applications, which, however, remains challenging due to the nearly indistinguishable physicochemical properties of enantiomers. In this study, we report a luminescent sensing strategy for enantioselective recognition based on metal-organic frameworks (MOFs) constructed through chiral linker exchange, which simultaneously introduces chirality and defective sites into the frameworks. The resulting chiral defective MOFs exhibit confined nanopore environments, resulting in distinct luminescence responses toward enantiomers. A pair of enantiomeric MOFs was constructed, exhibiting opposite selective recognition performance toward R- and S-substrates. The sensing behavior arises from the interplay of competitive absorption and electron transfer process, while disparities in binding affinities serve as the dominating factor dictating the enantioselectivity. Meanwhile, this system enables the quantitative detection of enantiomeric excess (ee) values in mixtures through differential luminescence responses. Due to its facile synthesis routes, selectivity, and ease of implementation, this strategy offers a practical approach for developing chiral luminescent sensing materials, while highlighting the significance of host-guest interactions in sensing.

Allyl-pyrocatechol and hydroxychavicol are catechol-type phenolic compounds from Piper betle that differ in the position of the allyl substituent, which may influence their electronic properties and antioxidant behavior. In this study, density functional theory (DFT) calculations were performed using the B3LYP functional with the 6-31 + G(2d,2p) basis set to investigate their frontier molecular orbital (FMO) characteristics and antioxidant mechanisms. Calculations were performed in gas and water phases using conductor-like polarizable continuum model (CPCM) solvation model. FMO analysis shows that hydroxychavicol exhibits a lower Eg in both phases (gas: 5.252eV; water: 5.273eV) compared to allyl-pyrocatechol (gas: 5.634eV; water: 5.808eV), suggesting relatively higher electronic reactivity and chemical softness. Solvent effects slightly increase the Eg of allyl-pyrocatechol, while hydroxychavicol remains relatively stable across phases. Thermodynamic evaluation indicates that formal hydrogen atom transfer (f-HAT) is more favorable in the gas phase based on bond dissociation enthalpy (BDE), whereas single electron transfer-proton transfer (SET-PT) is less competitive due to higher energetic requirements. In water phase, reduced ionization potential (IP) and proton affinity (PA) values suggest that solvation facilitates electron and proton transfer processes, making the sequential proton loss electron transfer (SPLET) pathway more relevant under polar conditions. Transition metal chelation (TMC), assessed via ΔHacidity, indicates position-dependent deprotonation tendencies that may contribute as a secondary antioxidant pathway. Overall, hydroxychavicol is more potential reactive, while allyl-pyrocatechol is predicted relatively more stable.

The reduction of ubiquinone is a critical step in cellular respiration thanks to its electron-accepting properties. Ubiquinone supports two distinct anionic states: a valence state and a non-valence, dipole-bound state. Dipole-bound states, where an excess electron is weakly bound by the molecular dipole, are of significant interest as potential doorway states for electron transfer processes. In this work, we employ the electron-attachment variant of the second-order approximate coupled-cluster (CC2) method to investigate the anionic states of ubiquinone analogues, Q0 and Q1. We characterize the conformational energy, molecular dipole, and dipole-bound state and valence state binding energies as a function of the two relevant coordinates of the system, which are the dihedral angles between the methoxy groups and the benzene ring. We find that the vertical electron affinity of the valence state varies by over thermally accessible regions, whereas the dipole-bound state appears discontinuously, governed by both dipole magnitude and orientation. Addition of a single isoprenoid unit to Q0, resulting in Q1, modestly reshapes the regions that support the dipole-bound state, but leaves the valence state surface essentially unchanged. Cluster scans with small molecules ( , HF, , and ) placed along the quinone dipole axis show that intermolecular interactions can modulate the electron affinity of the valence state by up to , far exceeding conformational tuning. The binding energy of the dipole-bound state is enhanced or quenched depending on dipole alignment. Larger cluster models focusing on bacterial reaction center reproduce the experimental finding that mutating an aliphatic isoleucine near the quinone to polar side chains leads to lower electron affinity, while mutation to the also hydrophobic valine leaves the electron affinity unchanged. Our results demonstrate how the biological and chemical environments can modulate the electron-accepting properties of ubiquinone and contribute to the discussion about the possible existence of dipole-bound anions in biological environments. Our findings highlight the interplay between molecular conformation, intermolecular interactions, and electronic structure in determining the redox properties of biologically relevant molecules.

Biotic-abiotic interfaced configurations hold great promise for application in renewable energy and artificial photosynthesis systems. Recent advances in synthetic biology, computational, and visualization techniques, along with enhanced high-resolution characterization, have enabled a deeper fundamental understanding of the interface, which, in turn, has improved electron transfer processes and the design architecture. These developed configurations open new routes to mimic the photosynthetic apparatus or add new applications based on biotic and abiotic catalytic reactions. Aiming to surpass natural systems, researchers have examined methods to reconfigure these block sets into new designs. This review focuses on the advances in artificial photosynthesis and coupled biotic-abiotic biohybrid systems. The work presents the development of artificial photosynthesis configurations aimed at generating light-induced energy or fuels. The use of natural photosynthetic proteins, inorganic photocatalysts, and advanced biohybrid materials is presented and discussed, aiming to enable future biotic-abiotic design and the ambitious goal of developing real-world applications.

Steel slag-embedded PVA-nanocellulose aerogel for high-capacity Cr(VI) removal: Unraveling the CaFe mediated synergistic adsorption-photocatalytic mechanism.

Excited-state ion radicals have recently attracted attention as powerful reductants or oxidants for electron-transfer photocatalysis. A key challenge in their application as photocatalysts is the short lifetime of their excited states, which directly impacts the efficiency of bimolecular photoinduced electron transfer. Here, we present a comprehensive photophysical study aimed at elucidating the factors that govern the lifetime of the doublet excited state in a series of 10 anion radicals derived from structurally related π-conjugated donor-acceptor-donor (DAD) molecules. In these systems, the acceptor is a 2,1,3-benzothiadiazole (BTD) unit flanked by arylene or oligo-(arylene) groups. The anion radicals, generated by chemical reduction in deoxygenated DMF, are stable and were characterized using UV-visible-near-IR absorption/emission spectroscopy and femtosecond transient absorption spectroscopy. Remarkably, the doublet excited state lifetimes vary by nearly 200-fold across the series, ranging from 2.9 to 565 ps. Nonradiative decay rates increase as the excited-state energy decreases, in a manner that is quantitatively consistent with the energy gap law for nonradiative decay. Faster decay is observed for anion radicals with highly delocalized π-systems, reflecting their lower excited-state energies. Finally, we demonstrate the catalytic utility of DAD anion radicals with long-lived doublet excited states in a consecutive photoinduced electron transfer (ConPET) process, using the photodebromination of 4-bromoacetophenone as a model reaction.

The electrochemical reduction of CO2 to CH4 in neutral electrolytes represents a compelling route toward carbon-neutral energy systems. Nonetheless, realizing a high Faradaic efficiency (FE) at industrially relevant current densities remains a formidable challenge, primarily due to the intrinsically slow kinetics of the multistep proton-coupled electron transfer (PCET) processes from CO2 to CH4. In this study, we propose an alternative active hydrogen (•H) transfer (AHT) process that significantly facilitates both CO2 activation and subsequent intermediate hydrogenation, thereby markedly enhancing the kinetics of CO2-to-CH4 conversion by designing a multivalent copper-based catalyst comprising Cu(0) nanoparticles and Cu(I) single atoms on an Al-MgO support. This novel catalyst achieved a CH4 Faradaic efficiency of ∼93.5% at a high current density of 350 mA cm-2 in a flow cell, substantially outperforming its monovalent counterpart (Cu(0)/Al-MgO, FE 55.4% at 300 mA cm-2) governed by a PCET-mediated pathway. Experimental studies and theoretical calculations demonstrate that the Cu(I) sites significantly lower the energy barrier for H2O dissociation, generating •H species that subsequently migrate to adjacent Cu(0) sites. These •H species effectively promote the hydrogenation of *CO to *CHO on Cu(0) sites, a key step in CH4 formation. Our findings highlight the critical role of tailoring hydrogenation pathways from traditional PCET to AHT mechanisms for advancing the efficiency and selectivity of electrocatalytic CO2-to-CH4 conversion.

Sulfate-reducing bacteria are among the main contributors to microbiologically influenced corrosion (MIC) through the production of corrosive sulfide species. In this work, Novobiocin, Jaceosidin, and Hispidulin were examined as potential inhibitors for suppressing MIC through surface adsorption and disruption of bacterial electron-transfer processes. Electronic structure analysis revealed that Novobiocin exhibits the smallest HOMO-LUMO energy gap (3.62 eV) compared with Jaceosidin (4.15 eV) and Hispidulin (4.17 eV), this behavior improved charge-transfer ability and stronger interaction potential with both the Fe surface and the biological target. Molecular docking results showed stronger binding affinities for Hispidulin (-4.66 kcal/mol) and Jaceosidin (-4.50 kcal/mol) toward Cytochrome c₃ compared to Novobiocin (-2.25 kcal/mol), this may contribute to interference with bacterial electron-transfer activity. Monte Carlo simulations also predicted strong adsorption on the Fe surface in the following order with the Fe surface, following the order: Novobiocin (232.23 kcal/mol) > Jaceosidin (171.84 kcal/mol) > Hispidulin (162.75 kcal/mol). DFT calculations were performed to investigate the electronic properties of the studied compounds. Docking calculations were conducted against Cytochrome c₃ (PDB ID: 1J0P) to evaluate ligand-protein interactions. Adsorption behavior on the Fe(110) surface was studied using Monte Carlo simulations and MD simulations under NVE conditions were used to examine the thermal stability of the inhibitor-surface systems using the COMPASSIII force field to evaluate the thermal stability and interaction dynamics of the inhibitor-surface systems.

The selective oxidation of ethylene (C2H4) and propylene (C3H6) offers the most important route for preparing a variety of platform chemicals. However, current industrial synthesis still relies on diversified thermo-oxidation methods, resulting in complex, inefficient, and high-cost production. Herein, we report a redox heterometallic cluster (TiIV16MnII4) catalyst capable of achieving unprecedented cascade oxidation of C2H4 and C3H6 to divergent products in a simple photoassisted electrochemical system. In situ characterizations combined with theoretical calculations disclose that under photoelectrochemical (PEC) operation, different electron transfer processes between the peripheral MnII centers and the internal {TiIV16O22} "electron reservoir" produce multiple active oxidation states (MnII → MnIV and TiIV → TiIII), which are able to activate multireactants and generate stabilized bromine radical (•Br) and hydroxyl radical (•OH) intermediates. As a result, the TiIV16MnII4 enables controlled tandem oxidation of C2H4/C3H6 to bromoethanol (BrCH2CH2OH)/bromopropanol (BrCH2CHOHCH3), ethylene oxide (EO)/propylene oxide (PO), and bromoacetic acid (BrCH2COOH)/bromoacetone (BrCH2COCH3) via shared (•Br + •OH)-dominated catalytic mechanisms, with high conversions (>99%), yields (up to 87%), and Faradaic efficiencies (FEs, up to 75%). Last but not least, this cascade catalytic system is applicable to a wide olefinic substrate scope as well as sustainable scaled-up production.

This study investigates the singlet oxygen O₂(¹Δg) generation capabilities and photophysical properties of eight synthesized alkoxy- and aryloxy-substituted BODIPY derivatives across eight different solvents. The production of O₂(¹Δg) was confirmed by monitoring its characteristic near-infrared (NIR) phosphorescence and through chemical trapping experiments using 1,3-diphenylisobenzofuran. Among the series, phenanthrenyloxy-BODIPY demonstrated outstanding performance, achieving a singlet oxygen quantum yield (ΦΔ) of up to 0.85. Photophysical analysis indicated that this high efficiency originates from a photoinduced electron transfer (PET) process within the molecule. All synthesized compounds exhibit significantly enhanced O₂(¹Δg) generation over the unsubstituted BODIPY reference (ΦΔ ≈ 0.10). The ΦΔ was found to be modulated by solvent polarity, while the carbon chain length of the alkoxy substituents has only a marginal influence. Density functional theory calculations, which reveals the spatial distribution of the highest occupied and lowest unoccupied molecular orbitals (HOMO/LUMO), provides further evidence for the proposed PET mechanism in phenanthrenyloxy-BODIPY. The established structure-property relationships offer valuable insights for designing efficient, heavy-atom-free BODIPY photosensitizers, with promising applications in photodynamic therapy for cancer.

Microorganisms living in nutrient- and energy-limited environments must finely coordinate anabolic and catabolic pathways. However, the molecular mechanisms underlying this balance remain poorly understood. Here, we report a mechanism cross-regulating amino acid biosynthesis and anaerobic respiration in bacterial cells. Using the model bacterium Shewanella oneidensis MR-1, we demonstrated that methionine activates extracellular electron transfer activity at submillimolar concentrations. This regulation is mediated by the transcription factor MetR, a canonical regulator of methionine biosynthesis. Under methionine-limited conditions, MR-1 upregulates methionine biosynthesis genes while repressing genes involved in extracellular electron transfer (metal reduction) and other anaerobic respiratory processes. Conversely, methionine availability relieves this repression, enhancing extracellular electron transfer. Furthermore, the MetR-mediated regulation of extracellular electron transfer was observed in Aeromonas hydrophila. These findings reveal a novel physiological role for MetR, suggesting its involvement in the coordinated energy distribution between anabolic and catabolic pathways.IMPORTANCEThis study identifies a novel regulatory link between methionine metabolism and anaerobic respiration. We show that Shewanella oneidensis MR-1 uses MetR to repress anaerobic respiratory pathways while activating methionine synthesis. This suggests a resource allocation strategy where bacterial cells prioritize the synthesis of "expensive" amino acids like methionine over the synthesis of respiratory machinery in amino acid-limited environments. Upon methionine availability, this suppression is lifted, boosting anaerobic electron transfer and energy production. Understanding this cross-regulation provides new insights into bacterial survival strategies and offers genetic targets for optimizing microbial electrochemical technologies, such as microbial fuel cells, where maximizing the extracellular electron transfer rate is critical.

Unveiling the sensing mechanism of a Nile Red-naphthoquinone H₂S fluorescent probe: theoretical calculation and deep learning prediction.

Half-sandwich ruthenium(II) complexes supported by phosphine ligands typically undergo one-electron oxidation processes at potentials that depend on the identity of the phosphine ligand. While in noncoordinating solvents these electron transfer (ET) processes are often quasireversible, electrochemical oxidation in the presence of exogenous ligands (such as in coordinating solvents) results in chemical reactivity of the nascent Ru(III) species. Herein, we report the synthesis and spectroscopic, structural, and electrochemical characterization of several series of (p-cymene)Ru complexes, including dichloride, solvento, bis(phosphine), and benzonitrile compounds. Based on extensive comparisons across these series of complexes and of Hammett analyses of the effects of phosphine-based substituents on Ru reduction potential, this ET-induced reactivity was confirmed to involve dissociation of the cymene moiety and incorporation of three nitrile ligands, with retention of the phosphine and chloride ligands present in the relative precursors. Investigations into the properties of the three isomers of [RuCl(PPh3)2(NCCH3)3]+, the byproduct of ET-induced reactivity of the [(p-cymene)RuCl(PPh3)2]+ complex, indicated the cis-(PPh3)2-fac-(CH3CN)3 isomer as the likely form of the complex generated following electrochemical oxidation, suggesting that ET-induced ligand exchange results in replacement of the facially coordinated arene ligand with three monodentate ligands also in a facial arrangement.

A dual-mechanism activated fluorescent chemosensor for nanomolar bismuth(III) detection with demonstrated real-sample, anticounterfeit, swab/strip, smartphone, imaging & logic-gate applications.

Piezo-Photothermal Accelerates Co3+/Co2+ cycle to Boost PMS Activation over Co3O4/PTFE for Efficient Antibiotic Degradation.

We have developed a versatile photocatalytic platform for the direct benzylation of diverse C(sp3)-H bonds using N-acyl carbamothioates derived from readily available alcohols as benzyl radical precursors. This protocol operates through two complementary manifolds: a consecutive photoinduced electron transfer (Con-PET) process for the benzylation of N-α-C(sp3)-H bonds and a thiol-mediated hydrogen atom transfer (HAT) cycle for more challenging substrates including alkenes, ethers, thioethers and toluenes. This deoxygenative strategy enables efficient C(sp3)-C(sp3) radical-radical cross-coupling without transition-metal-coupling catalysts, external oxidants, or radical stabilizers, delivering the desired products in moderate to good yields (up to 70%).

Bismuth oxide (Bi2O3) holds great potential for the selective electroreduction of CO2 to formate, yet its practical application is hindered by rapid cathodic reduction to metallic Bi0 and competing hydrogen evolution under industrially relevant conditions. Herein, we report a scalable solvothermal method to synthesize free-standing, three-atom-thick (∼1.25 nm) Bi2O3 nanosheets (3L-Bi2O3) that simultaneously achieve antireduction stability and tunable protonation kinetics for efficient CO2-to-formate conversion. Potentiodynamic XAS and Raman spectroscopies reveal that compressive strain induced by atomic-layer thinning strengthens Bi-O bonds, as evidenced by ∼11.5% Bi0 formation at -1.0 V vs RHE, compared to ∼65.7% for bulk-Bi2O3 at -0.6 V vs RHE. Consequently, 3L-Bi2O3 maintains a formate Faradaic efficiency of >90% and durability for ∼50 h at 200 mA cm-2 in 1.0 M KHCO3 solution. In situ infrared spectroscopy and differential mass spectrometry combined with kinetic analyses identify HCO3- as the essential proton donor in the two-step sequential proton-coupled electron transfer (PCET) process. In contrast to bulk-Bi2O3, 3L-Bi2O3 exhibits a distinct volcano-shaped dependence of formate selectivity on HCO3- concentration, reflecting a trade-off between sufficient proton availability for *OCHO formation and suppression of competitive hydrogen evolution. This behavior originates from the weakened *H adsorption and stabilized *OCHO intermediates on an atomically thin Bi2O3 surface, which shift the rate-determining step from the initial PCET step (as in bulk-Bi2O3) to the subsequent *OCHO protonation, as confirmed by free energy profiles and electronic structure analyses, including charge density differences, Bader charge analysis, and projected density of states.