Mitochondrial deenergization by lipophilic uncouplers is known to be reversed by 6-ketocholestanol (kCh), whereas with 2,4-dinitrophenol (DNP), a hydrophilic uncoupler, kCh does not cause mitochondrial recoupling. Here, we synthesized 2-alkylamino-4,6-dinitrophenol derivatives, varying alkyl from ethyl to dodecyl. All of them exhibited uncoupling of isolated rat mitochondria, with the most potent 2,4-dinitro-6-octylaminophenol acting at submicromolar concentrations. The octylamino derivative showed 100 times higher ability to induce electric current through planar bilayer lipid membrane than DNP. Mitochondrial recoupling by kCh was found for hexylamino and octylamino derivatives, whereas kCh-induced noticeable stimulation of the uncoupling, probably due to membrane dipole potential elevation, instead of the recoupling, was observed for the ethylamino analogue and DNP itself. By measuring a kCh-induced decrease in surface tension at the air-water interface in parallel with an increase in ANS fluorescence upon binding to kCh, we showed an ability of kCh to form micelles with CMC of 10 μM. The micelles readily bound hydrophobic uncouplers, such as the octylamino DNP analogue and CCCP, but less effectively bound DNP and its ethylamino analogue. Therefore, the recoupling by kCh could be associated with direct interaction between hydrophobic protonophores and kCh micelles, preventing the former from binding to mitochondrial membranes.
We developed thermo- and photo-switchable electrodes based on a hybrid composite of carbon nanofibers (CNFs), thermo-responsive poly(N-isopropylacrylamide) (PNIPA), and gold nanoparticles (AuNPs). These electrodes were fabricated via electrochemical methods to achieve efficient electrochemical communication with dopamine. The electrochemically active surface area of AuNPs electrodeposited on the CNF electrode with extended PNIPA brushes at 25 °C (CNF/PNIPA/AuNP) was about (4.98 ± 0.64) × 10-2 cm2 and approximately four times larger than that with contracted PNIPA brushes at 45 °C (ca. (1.25 ± 0.03) × 10-2 cm2). The electron transfer rate for dopamine at the former electrode was higher than those at the latter electrode and an electrode modified in the reverse order AuNPs and PNIPA (CNF/AuNP/PNIPA). This enhancement is attributed to the surface-exposed AuNPs, which are not covered with PNIPA brushes. The CNF/PNIPA/AuNP electrode also exhibited switchable behavior based on the collapsed globule PNIPA induced by either high temperature (45 °C) or NIR light irradiation at 25 °C. This transition inhibited dopamine diffusion to the electrode surface due to steric hindrance, consequently decreasing the redox current. These findings provide a basis for developing novel hybrid functional nanomaterial composite electrodes with tunable electrochemical activity for smart device applications.
Seasonal temperature fluctuations in buried thermal pipelines strongly affect microbial growth and associated corrosion. This study examines the influence of temperature and carbon source concentration on Q235B steel corrosion induced by Desulfovibrio ferrophilus. Results demonstrate that D. ferrophilus remains metabolically active even at 85 °C, indicating high thermal adaptability. Corrosion current densities increased with temperature and carbon availability, reaching 5.44 μA·cm-2 at 85 °C under high lactate. Surface analyses (SEM and CLSM) reveal pitting corrosion driven primarily by microbial adhesion, which is enhanced at elevated carbon levels. Electrochemical studies indicate that at 37 °C, carbon concentration significantly affects both anodic and cathodic reactions, reflecting extracellular electron transfer (EET) activity. Corrosion products are dominated by pyrite (FeS), with content modulated by temperature and carbon supply. Overall, high temperature and microbial activity synergistically accelerate Q235B steel corrosion, while localized corrosion is closely linked to microbial biofilms and EET processes. These findings elucidate the mechanistic role of temperature and nutrient availability in microbiologically influenced corrosion of thermal pipeline steel under realistic operational conditions.
This work reports the development of a robust electrochemical sensing interface for the selective and sensitive quantification of tryptophan (Trp). The sensor architecture was constructed from a cobalt-doped manganese dioxide framework anchored onto nitrogen-doped carbon nanotubes (Co@MnO₂/N-CNTs). The 3-D composite, synthesized via a straightforward hydrothermal strategy, exhibited a highly porous and uniformly distributed morphology with intimate interfacial coupling between the components. Comprehensive structural and compositional analyses using SEM, HRTEM, and XPS confirmed the successful formation of the Co@MnO₂/N-CNT hybrid. The combination of redox-active Co, high-surface-area MnO2, and conductive N-CNTs improved the movement of electrons and made the sensor work better for detecting Trp. Electrochemical studies demonstrated excellent catalytic performance toward Trp oxidation, with a wide linear range of 0.5-300 μM and a low limit of detection 0.062 μM (S/N = 3). The sensor displayed high sensitivity, repeatability (RSD < 2.7%), and reproducibility (RSD < 4.1%). Furthermore, the developed sensor exhibited excellent anti-interference performance and was effectively employed for the quantification of Trp in human plasma samples, achieving satisfactory recovery rates between 93.0% and 105.5%. This work provides a promising approach for the design of multifunctional nanomaterials for bioanalytical applications.
This work describes a label-free electrochemical immunosensor for the non-invasive detection of tumor necrosis factor-α (TNF-α) in human saliva. The sensing platform utilizes a hierarchical nanocomposite comprising hemp-derived nanocellulose (HNC), polyvinyl alcohol (PVA), PEDOT:PSS, and electrodeposited gold nanoparticles (AuNPs). The porous 3D HNC network provides a biocompatible scaffold for efficient antibody immobilization, while the integrated conductive matrix significantly accelerates electron transfer kinetics. Under optimized conditions, the immunosensor exhibits a linear range of 5-300 pg mL-1 with a limit of detection (LOD) of 3.91 pg mL-1 and excellent selectivity against common interferents. Validation with clinical saliva samples demonstrated strong correlation with standard ELISA, confirming the platform's potential for point-of-care inflammatory biomarker monitoring.
Alzheimer's disease (AD) is the leading cause of dementia, and early identification of molecular biomarkers in blood offers a promising avenue for diagnosis and monitoring treatment. Tau-441 stands out as a particularly promising biomarker among the potential molecular targets. This research describes the development of a highly sensitive and cost-effective biomimetic sensor, capable of selectively detecting Tau-441 at femtomolar concentrations. This is achieved through the synergistic combination of gold nanoparticles (AuNPs) with molecularly imprinted polymer (MIP) technology. The MIP layer was sensitised by electropolymerising phenylenediamine (o-PDA) in the presence of Tau-441 and AuNPs onto a gold screen-printed electrode (Au-SPE) using cyclic voltammetry (CV). After polymerisation, the entrapped proteins were removed by proteolytic digestion, generating well-defined imprinted cavities within the polymer matrix. Scanning electron microscopy (SEM) and Raman analysis were conducted to monitor the surface modification of the Au-SPE working electrode. The device displayed linear responses to Tau-441 protein within the range 2.0 pg mL-1 to 200 ng mL-1, with a limit of detection of 1.51 fg mL-1. The analytical performance of the device was validated in complex matrices, including Cormay serum and cell media from primary cultures of hippocampal neurons, using a competitive assay. The platform showed high sensitivity, good reproducibility, and reliable performance in biologically relevant media, demonstrating strong robustness. Its excellent analytical characteristics, together with the potential for integration into portable electrochemical devices, make this sensor a promising tool for rapid and accurate point-of-care testing, enhancing the detection and monitoring of AD.
Electronics in the field of health care endures rapid changes. It covers a wide range of therapeutic pathways and medical devices. Wound therapy mediated by electrical impulse has the potential to reduce bacterial growth and enhance the healing of wounds. In this work, we were targeting bacterial cell membrane by means of electrode generated impulse for log phase restriction and quorum sensing-dysregulation. A low voltage electrical impulse significantly reduced the bacterial growth up to 80.8% for E.coli, 81.38% for P.aeruginosa, 67.2% for S.aureus and 36.55% for E. faecalis. The impluse affects the selective permeability of the bacterial cell membrane by causing electrochemical changes at the membrane, restricting the bacterial multiplication. Transient pore formation in bacterial membrane was confirmed by the release of lactate dehydrogenase by both gram-negative (65%) and gram-positive bacteria (16.7%). Quorum sensing dysregulation occurred due to the disruption of exopolysaccharides up to 45% for S.aureus and biofilm up to 35% for P.aeruginosa. This influences the bacterial multiplication as reduction in exopolysaccharides hinders the communication between bacteria. The bacterial respiratory chain varies by 16-80. This results in the disruption of energy production and metabolic imbalance in bacteria which ultimately supresses the bacterial proliferation.
Tanshinone IIA is a bioactive component of diterpenoid tanshinones and has broad application potential in the treatment of cardiovascular and cerebrovascular conditions. In this study, we aimed to fabricate an electrochemical sensor for detecting tanshinone IIA. For this purpose, we developed a novel composite electrode material, CeO2-Au/MoS2/MWCNTs. The CeO2-Au nanozyme was synthesized using a hydrothermal method and subsequently integrated onto a MoS2/MWCNT nanostructure for the detection of tanshinone IIA. This electrode material demonstrates superior electron transfer efficiency and catalytic performance, facilitating the fast and accurate detection of tanshinone IIA. Transmission electron microscopy and X-ray diffraction were utilized to identify and characterize its nanostructure and elemental composition. Under optimized conditions, an enzyme-free detection system for tanshinone IIA was developed, exhibiting a broad linear range and a low detection limit of 15 nM. Furthermore, the results demonstrated that the sensor exhibited good stability and reliable accuracy in detecting tanshinone IIA in natural samples. This work introduces a highly efficient sensor for detecting diterpenoid tanshinones and contributes to the broader application of nanozyme materials in electrochemical sensing.
This study aimed to investigate the synergistic effect of cold atmospheric plasma (CAP) and pulsed electric field (PEF) in inducing immunogenic cell death (ICD) in triple-negative breast cancer (TNBC) cells. CAP and PEF devices were self-developed. MDA-MB-231 cell line was used and divided into five groups: Control, CAP, PEF, CAP before PEF, and PEF before CAP. Optical emission spectroscopy confirmed that CAP produced reactive species such as He, OH, N₂ and O, and infrared thermal imaging showed that the maximum temperature during the treatment did not exceed 28.3 °C. CAP could significantly increase the content of H₂O₂, NO₂- and NO₃- in PBS. Scavenger experiments showed that the cytotoxicity of CAP was completely reversed by Catalase and N-Acetylcysteine (NAC), while that of PEF was only reversed by NAC. Furthermore, CAP before PEF treatment had the strongest killing and pro-apoptotic effects on TNBC cells, and the increase in ICD markers was the most significant. Mechanically, pre-treatment with CAP allowing PEF to cause more extensive membrane disintegration. CAP before PEF treatment also triggered the most intense mitochondrial oxidative stress, leading to a significant rise in intracellular reactive oxygen species (ROS) levels.
Directly connected to an electrode, high potential MCOs catalyse the oxygen reduction reaction (ORR) at low overpotential with high efficiency. MCOs contain two redox centers, a near surface-located mononuclear copper (T1) oxidising a substrate and a buried trinuclear copper center (TNC) reducing dioxygen to water. Which of the two copper centers is directly wired to the electrode during the bioelectrocatalytic reduction of dioxygen is a challenging question to address. Beyond potentially improving the direct electron transfer process, the rational orientation of a high potential MCO should allow to bypass the rate-limiting internal electron transfer from T1 to TNC and enhance the ORR efficiency. Variants of a high potential fungal laccase (LAC3) isolated from Trametes sp. C30 were designed to target two opposite orientations in which the T1 copper center is either as close (T1-orientation) or as far (anti-T1 orientation) as possible from the MWCNT electrode. Analysis of the electrochemical response of these variants under different conditions allow to conclude: (1) the T1 center is the first electron acceptor in randomly adsorbed enzymes, (2) pyrene-enzyme hybrids allow for a selective wiring of T1 and TNC sites to MWCNTs and (3) anti-T1 oriented hybrids are three-fold more efficient for ORR.
T lymphocytes play a central role in the adaptive immune system, and the regulation of their activity is of critical importance. As an emerging therapeutic approach, accumulating evidence supports that atmospheric pressure plasma (APP) exerts anti-tumor effects by activating the immune function and inducing immunogenic cell death, thereby inhibiting tumor growth. However, it remains unclear whether APP has any effect on the activation of T cells. This study investigates the effect of APP on T cell activation and subset. We demonstrate that APP pretreatment increases both intracellular and extracellular reactive oxygen and nitrogen species (RONS) level in anti-CD3/28-stimulated Jurkat T cells, promoting proliferation, upregulating the activation markers CD69 and CD25, and enhancing the secretion of IL-2 and IFN-γ. Proteomic analysis revealed an activation of T cell receptor signaling pathway in the peripheral blood of rats after APP inhalation. Furthermore, flow cytometry demonstrated that APP inhalation increased the proportion of regulatory T cells in the peripheral blood of both normal rats and rats with cerebral ischemia, and ameliorated ischemic cerebral infarction. These findings suggest that APP can further activate T cells based on co-stimulatory signals, supporting its further investigation in immunomodulation.
Deep eutectic solvents (DESs) are a group of emerging solvents for biocatalysis with tailored performance. Herein, we report the usage of hierarchical zeolitic imidazole framework-8 (HZIF-8) and halogenated DES for the immobilization of phenylalanine dehydrogenase. Effects of three different halogenated DESs (I, Cl and Br) on the activity of immobilized enzymes for production of homophenylalanine were studied. The optimal activity towards with the model reaction of catalyzing ethyl 2-oxo-4-phenylbutyrate (EOPB) to L-homophenylalanine was 6.11 U/mg at 70 °C, 5.4-fold of that of the free enzyme, with 78.4% of its original activity retained after six recycles. The immobilized enzymes were further loaded on a poly(methylene blue) electrode with electrochemical NAD+ regeneration, leading to bioelectrosynthesis of phenylpyruvate. Using phenylalanine-ethanolamine (Phe-MEA) as the substrate, 13.85 mM phenylpyruvate was obtained after 8 h, with a total turnover number (TTN) value of 138.5 for NADH regeneration, while a TTN of 102.2 using L-Phe as the substrate.
Breast cancer, a globally prevalent malignancy in women, requires early diagnosis to improve patient outcomes, where ctDNA serves as a key biomarker. In the present study, an electrochemical biosensor based on CRISPR/Cas12a and Au@UiO-66 nanozyme synergistic dual amplification was developed to achieve ultrasensitive detection of breast cancer marker ctDNA. Au@UiO-66-modified ssDNA probes were anchored to the gold electrode via thiol groups. The intact ssDNA probe anchors Au@UiO-66 nanozyme to the electrode, where its peroxidase-like activity efficiently catalyzes H2O2 reduction to generate amplified reduction peak currents. Target ctDNA activates Cas12a's trans-cleavage capacity by binding specifically to crRNA. Under the presence of the target, Au@UiO-66 nanozymes are released, resulting in a discernible drop in the peak current linked to H2O2 reduction. Benefiting from the optimized experimental conditions, the biosensor demonstrates a broad linear detection range (from 10 fM to 10 nM) for the target ctDNA, along with an exceptionally low detection limit of 6.14 fM. Successful detection in human serum samples demonstrates its practicality. The platform's high specificity is attributed to the programmable crRNA design, enabling detection of specified DNA sequences and showcasing significant adaptability for diagnosing multiple genetic targets, highlighting its potential in clinical cancer diagnosis.
Interleukin-6 (IL-6) is an inflammatory cytokine that plays a crucial role in cancer, with its elevated level being indicative of metastasis. Oral squamous cell carcinoma (OSCC) is a major type of head and neck cancer and IL-6 has been identified as a critical factor that is overexpressed in its development, progression and metastasis. IL-6 is also associated with various pathological processes, such as chronic inflammation, cancer and severe COVID-19 infection. This study aims to develop an affordable, simple manufacturing process for a user-friendly, label-free electrochemical immunosensor to detect IL-6 in a real-time manner in artificial saliva. Carbon nanotube field-effect transistor (CNT-FET)-based sensor was fabricated and transfer and output curves were measured and the device sensor exhibited p-type semiconductor properties. Under optimized experimental parameters, the fabricated CNT-FET-based immunosensing platform can detect IL-6 antigen with a wide detection range from 1.0 to 300 pg/mL with a relatively low detection limit (LOD) of 1.15 pg/mL in 1.0 mM PBS. Additionally, the developed immunosensor showed outstanding specificity, sensitivity, good repeatability and high stability in 1.0 mM PBS. Furthermore, the fabricated immunosensor was successfully used in artificial saliva samples spiked with IL-6 and recovery percentages were in the range of 102 to 104.5%.
This study investigated the microbiologically influenced corrosion (MIC) of Al-Zn-In-Cd sacrificial anode in the simulated marine tidal environment, elucidating the corrosion mechanism arising from the interaction between microorganisms and dynamic marine tide. Results revealed significant spatial variations in corrosion distribution, with the fully immersed zone (FIZ) exhibiting the most severe corrosion. Metabolic activity of Pseudomonas sp. enhanced anodic dissolution, markedly increasing the corrosion rate and raising the corrosion current density (icorr) by an order of magnitude. Furthermore, it altered the composition of corrosion products, forming loose and porous iron-rich products that compromised the protective qualities of corrosion products. Periodic wet-dry cycles further destabilized the corrosion products and accelerated pitting. These findings offer insights that inform the optimization of material design and improve the service life of Al-Zn-In-Cd sacrificial anodes in marine tidal environments.
Microbiologically influenced corrosion (MIC) of carbon steel by sulfate-reducing bacteria (SRB) is a major challenge in oil and gas systems, particularly because of its strong tendency to cause localized attack. Cementite is a common conductive microstructural phase in carbon steels, yet its role in SRB-induced MIC has not been well clarified. In this work, pure iron, 10# steel, and 45# steel with different cementite contents were investigated in sterile and SRB-containing media using surface characterization, corrosion product analysis, pitting quantification, and electrochemical measurements. The results showed that increasing cementite content was associated with more severe localized corrosion, as evidenced by the increased maximum pit depth and broader pit size distribution, while the average corrosion rate did not exhibit a clear monotonic trend. Etched specimens with greater cementite exposure showed further aggravation of pitting, indicating that exposed cementite plays an important role in the corrosion process. Electrochemical results and surface observations suggest that conductive cementite facilitates interfacial electron transfer between sessile SRB and the steel substrate, thereby promoting localized MIC. These findings provide evidence that steel microstructure, especially cementite-containing phases, is an important factor governing SRB-induced pitting and should be considered in the microstructural design of MIC-resistant carbon steels.
Nutrition competition exists in the tumor microenvironment (TME), which is considered as an important factor of T cell exhaustion. Various amino acids are the targets for both tumor cells and T cells, including L-Tyr, which plays an essential role in normal function of T cells. Herein, a novel sensing interface of MIP/Fc/PEDOT:PSS-PPy/graphite/Au established on a PCB substrate, was proposed for L-Tyr detection. This sensor was systematically characterized and showed excellent repeatability, stability, reproducibility, and specificity. Meanwhile, the sensor exhibited good detection capability, with a linear range of 1 nmol/L to 1 mmol/L, a limit of detection of 1.62 × 10-11 mol/L, and a sensitivity of 97.14 μA/(mol/L). An in-vitro co-culture model of T cells and tumor cells was established to mimic the TME, and its culture medium was used as real samples for L-Tyr determination via the proposed sensor. The results demonstrated that the failure of L-Tyr competition by T cells in the TME was a vital cause of their exhaustion, which was further validated by the IL-2 expression of T cells within the TME using ELISA. Collectively, our study is expected to provide a new strategy for tumor treatment, by supplementing exogenous amino acids to alleviate T cell exhaustion.
Biorefineries offer a sustainable model that supports circular economy and nutrient recovery from waste feedstocks. Biorefineries were centered on microalgae for biomass and biofuel generation, but the concept has shifted toward inclusion of more versatile microorganisms to cope with diversity of waste substrates. Purple phototrophic bacteria (PPB) are particularly interesting, as they can treat wastewater while producing biomass, polyhydroxybutyrate (PHB), and carotenoids. Furthermore, PPB can utilize electrodes as extracellular electron donors, enhancing the synthesis of these products. Additionally, electrochemical moving bed reactors have been shown to improve PHB production by supporting electroactivity in planktonic cells. In this study, a photo microbial electrochemical moving bed reactor (photoME-MBR) was scaled up from 250 mL to 50 L, which constitutes the largest example for a bioelectrochemically-assisted PPB case study. The new configuration was operated under cathodic conditions to assess biomass, PHB, and carotenoid production; brewery wastewater treatment efficiency, and bioelectrochemical performance. Synthesis of value-added products at pilot scale was comparable to laboratory-scale productivity, while achieving organic pollutants removal at a rate of 136 gTOC/m3·d. Cathodic polarization significantly enhanced PHB production (100 mgPHB/gDryBiomass) by promoting extracellular electron uptake from the conductive bed. Microbial community analysis identified Rhodopseudomonas sp. and Bradyrhizobium sp. as dominant genera.
Extracellular electron transfer (EET) is crucial in microbial energy-conversion technologies. However, broad application is hindered by insufficient charge transfer from microbes to electrodes. Fumarate, although should theoretically inhibit EET as a competing electron acceptor, was shown to moderately enhance EET in Shewanella oneidensis MR-1. In this work, a 50-fold increase in EET currents in the presence of 30 mM fumarate is demonstrated, leading to a 100-fold reduction in electrical resistance to biocurrents based on electrochemical impedance spectroscopy analysis. A fast decrease in currents following the depletion of fumarate and a rapid increase upon reintroducing fumarate revealed hitherto unreported EET dynamics. Through enzymatic assays, the ratio of electrons channeled from lactate metabolism into fumarate reduction and EET, and the concentrations of fumarate necessary for days-long high EET are determined. These new aspects promise to contribute to the development of more efficient microbial technologies without employing any genetic and even materials modifications.
A hybrid biosensing platform was developed for ultrasensitive detection of the SARS-CoV-2 nucleocapsid (N) protein by integrating an antibody-engineered magnetic bimetal-organic framework with a graphene field-effect transistor (GFET) readout. In this design, Fe₃O₄@SiO₂@Ce-Zr MOF particles were prepared and functionalized with an anti-SARS-CoV-2 N protein antibody (AntiE2) to selectively capture the N protein in phosphate-buffered saline (PBS). After magnetic enrichment and washing with PBS, the resulting immune complexes were interfaced with a GFET to convert the biorecognition event into an electrical signal. The device response exhibited a linear relationship over concentrations from 1 ag⋅mL-1 to 10 ng⋅mL-1, achieving a limit of detection of 4.08 ag⋅mL-1. The feasibility of this strategy was further verified in serum matrices, supporting its potential for sensitive detection in complex biological samples.