Ion Pumps Research Articles

Therapeutic potential of 2S-hesperidin against the hepatotoxic effects of dichlorvos in rats.

Dichlorvos (DDVP) is an organophosphate insecticide that enhances food production and repels disease vectors. However, it provokes cytotoxicity. 2S-hesperidin (2S-HES) is a potent antioxidant, anti-inflammatory, and anti-lipidemic flavanone. Regardless, the 2S-HES impact on DDVP-occupied hepatic injury remains fuzzy. We evaluated the therapeutic potential of 2S-HES in a rat model of DDVP-elicited hepatic intoxication. Forty-two rats were randomly allotted to seven groups (n=6/condition): control, DDVP (8mgkg⁻1day⁻1), DDVP with 2S-HES (50 and 100mgkg⁻1day⁻1), DDVP with atropine, and 2S-HES alone (50 and 100mgkg⁻1day⁻1). DDVP was administered orally for 7 days, followed by 14 days of 2S-HES chemotherapy. 2S-HES intervention partially mitigated DDVP-triggered alterations in leakage enzymes (ALT, AST, ALP, LDH-5), total protein, albumin, globulin, bilirubin, electrolytes, ion-transporters, lipid profiles, and HMG-CoA reductase. Furthermore, 2S-HES partially reversed DDVP-provoked increases in hepatic H₂O₂, NO, and malondialdehyde; transposed DDVP-mediated decreased liver GSH amount and activities of GST, SOD, catalase, and GPx; attenuated DDVP-triggered upregulated NF-κB-p65 and caspase-3; and abated DDVP-engendered repressed interleukin-10 mRNA expression. Cytoarchitectural analyses authenticated the 2-HES reduction in DDVP-evoked hepatocellular vacuolation. Altogether, 2S-HES elicited promising alternative or adjunctive therapy for partially mitigating DDVP-incited hepatic injury by attenuating leakage enzymes, ionoregulatory disruptions, ion pump inhibition, dyslipidemias, oxidative stress, inflammation, and apoptosis.

Electrostatically self-assembled Fe3O4@Ti3C2Tx electrodes for efficient capacitive deionization driven by ultrafast ion pumps

Electrostatically self-assembled Fe3O4@Ti3C2Tx electrodes for efficient capacitive deionization driven by ultrafast ion pumps

Dual-Loop Charge Management for Space-Based Gravitational Wave Detection

In space-based gravitational wave detection missions, inertial sensors act as the inertial reference, requiring the test mass (TM) to maintain exceptionally low residual acceleration noise. High-energy particles, cosmic rays, and ion pumps during ground tests can quickly lead to charge accumulation on the TM surface, necessitating a charge management system to regulate surface charges. To manage the TM surface potential, this paper develops a mathematical model of the charge management system using established ultraviolet (UV) discharge simulation methods. The model describes how photoelectron emission or absorption on the TM surface varies with UV light-emitting diodes (LEDs) power and bias voltage. For the first time, a dual-loop control method is implemented for charge control, highlighting its practical significance. The controller precisely regulates the TM surface potential and residual charges to specified values, achieving a control accuracy of 1.1×106e, meeting the stringent requirements of space-based gravitational wave detection missions. This approach offers a closed-loop charge management solution and provides valuable insights for designing future charge management systems.

Regulating Water Molecules via Bioinspired Covalent Organic Framework Membranes for Zn Metal Anodes.

The Zn metal anode in aqueous zinc-ion batteries (AZIBs) faces daunting challenges including undesired water-induced parasitic reactions and sluggish ion migration kinetics. Herein, we develop three-dimensional covalent organic framework (COF) membranes with bioinspired ion channels toward stabilized Zn anodes. These COFs, featured by zincophilic pyridine-N sites, enable effective regulation of water molecules at the anode-electrolyte interphase. Systematic experimental analysis and theoretical simulations reveal the optimized COF-320N membrane functions as ion pumps, accordingly facilitating Zn2+ transport and inhibiting direct contact between Zn anode and free water molecules. Consequently, the bio-inspired strategy achieves improved Zn2+ transference number (0.61), rapid de-solvation kinetics, and suppressed hydrogen evolution. The assembled Zn||MnO2 pouch cell integrated with COF-320N membrane exhibits favorable electrochemical performances. Such a bioinspired concept for optimizing Zn anodes opens new pathways in developing advanced energy storage devices.

Regulating Water Molecules via Bioinspired Covalent Organic Framework Membranes for Zn Metal Anodes

The Zn metal anode in aqueous zinc‐ion batteries (AZIBs) faces daunting challenges including undesired water‐induced parasitic reactions and sluggish ion migration kinetics. Herein, we develop three‐dimensional covalent organic framework (COF) membranes with bioinspired ion channels toward stabilized Zn anodes. These COFs, featured by zincophilic pyridine‐N sites, enable effective regulation of water molecules at the anode‐electrolyte interphase. Systematic experimental analysis and theoretical simulations reveal the optimized COF‐320N membrane functions as ion pumps, accordingly facilitating Zn2+ transport and inhibiting direct contact between Zn anode and free water molecules. Consequently, the bio‐inspired strategy achieves improved Zn2+ transference number (0.61), rapid de‐solvation kinetics, and suppressed hydrogen evolution. The assembled Zn||MnO2 pouch cell integrated with COF‐320N membrane exhibits favorable electrochemical performances. Such a bioinspired concept for optimizing Zn anodes opens new pathways in developing advanced energy storage devices.

Large, recursive membrane platforms are associated to Trop-1, Trop-2 and protein kinase signaling for cell growth.

The transmembrane glycoproteins Trop-1/EpCAM and Trop-2 independently trigger Ca2+ and kinase signals for cell growth and tumor progression. Our findings indicated that Trop-1 and Trop-2 tightly colocalize at macroscopic, ruffle-like protrusions (RLP), that elevate from the cell perimeter, and locally recur over hundreds of seconds. These previously unrecognized elevated membrane regions ≥20 µm-long, up to 1.5 µm high were revealed by Z-stack analysis and three-dimensional reconstruction of signal transducer-hosting plasma membrane regions. Trop-2 stimulates cell growth through a membrane super-complex that comprises CD9, PKCα, ion pumps and cytoskeletal components. Our findings indicated that the growth-driving Trop-2 super-complex assembles at RLP. RLP behaved as sites of clustering of signal transducers, of phosphorylation/activation of growth-driving kinases, as recruitment sites of PKCα and as origin of Ca2+ signaling waves, suggesting RLP to be novel signaling platforms in living cells. RLP were induced by growth factors and disappeared upon growth factor deprivation and β-actin depolymerization, candidating RLP to be functional platforms for high-dimensional signaling for cell growth. [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text].

EMPLOYING THIN PLANAR ELECTRODES TO EXPAND THE IONIC WIND FLOW COVERAGE AREA AND ACHIEVE ENHANCED HEAT DISSIPATION

The suboptimal photoelectric conversion efficiency of light-emitting diodes (LEDs) leads to increased temperature. There is a growing interest in using microstructure ionic wind pumps to regulate the chip temperature. But the ionic wind flow and thermal transfer characteristics of thin-plate electrode pumps used for cooling LED chips is unclear. This study proposes ionic wind pumps equipped with wedged and zigzag emitters to effectively manage the heat generated by high-power LED chips. Experimental investigations were conducted to analyze the electrohydrodynamic characteristics of pumps with different emitter types. A two-dimensional model with a wedged electrode and a three-dimensional model with a zigzag electrode were developed for flow distribution analysis and energy efficiency comparison. The cooling capacity of pumps with different configurations was examined. The results show that the pump equipped with a zigzag electrode exhibits improved stability in corona discharge and approximately 1.53 times higher energy efficiency compared to the pump with a wedged electrode. Moreover, the pump with the zigzag electrode covers a larger ionic wind flow area, generating a higher intensity of ionic wind. The angle between the emitter and the grounding electrode significantly affects the ionic wind flow characteristics. The optimal angle is 70° for pumps with wedged emitters and 30° for those with zigzag emitters. Both pumps can produce a steady wall jet at their optimal angle, causing significant disruption in the surrounding area. The pump with a zigzag electrode exhibits superior cooling performance and is more effective with low power consumption.

A dynamically assembled bionic ion pump interface towards high-rate and stable-cycling zinc metal batteries

A bionic ion pump interface is developed by introducing acetylated proteins (α-HPace) with strong Zn2+ recognition ability.

Enabling structural biological electron paramagnetic resonance spectroscopy in membrane proteins through spin labelling.

Pulsed dipolar electron paramagnetic resonancespectroscopy (PDS), combined with site-directed spin-labelling, represents a powerful tool for the investigation of biomacromolecules, emerging as a keystone approach in structural biology. Increasingly, PDS is applied to study highly complex integral membrane protein systems, such as mechanosensitive ion channels, transporters, G-protein coupled receptors, ion pumps, and outer membrane proteins elucidating their dynamics and revealing conformational ensembles. Indeed, PDS offers a platform to study intermediate or lowly-populated states that are otherwise invisible to other modern methods, such as X-ray crystallography, cryo-EM, and hydrogen-deuterium exchange-mass spectrometry. Importantly, advances in spin labelling strategies welcome a new era of membrane protein investigation under near-native or in-cell conditions. Here, we review recent integral membrane protein PDS applications, and highlight well-suited, emerging spin labelling strategies that show promise for future studies.

Organization of the stalk system on electrocytes in mormyrid weakly electric fish Campylomormyrus compressirostris

The adult electric organ in weakly electric mormyrid fish consists of action-potential-generating electrocytes, structurally and functionally modified skeletal muscle cells. The electrocytes have a disc-shaped portion and, on one of its sides, numerous thin processes, termed stalklets. These unite to stalks leading to a single main stalk that carries the innervation site. Here, we describe the 3-dimensional layout of the stalklet/stalk system in adult Campylomormyrus compressirostris by differential interference contrast microscopy and confocal fluorescence microscopy. Using antibodies against Na+/K+-ATPase α-subunit and plasma membrane Ca2+-ATPase, we show that these ion pumps are differentially distributed over the stalklet/stalk system, with plasma membrane Ca2+-ATPase being enriched on the stalklet membrane. Stalklets are distributed and organized in a quite uniform pattern on the posterior face of the electrocyte disc and fuse to terminal stalks. The latter then unite in a mostly dichotomic mode to stalks of increasing thickness, with the main stalk measuring about 100 µm in diameter. We further analyse the structural organization of stalklets and stalks, with a characteristic cytoskeletal system of bundled actin filaments in the centre and nuclei in subsurface position. These results suggest that the stalklet/stalk system is adapted in its structural layout to generate an action potential highly synchronized over the entire disc-portion of the electrocyte, accounting for the short electric organ discharge in this species. Our results suggest that actin-related proteins overexpressed in electrocytes, as shown previously by transcriptome analysis, may be involved in the organization of the unique F-actin system in stalklets and stalks.

Powering a molecular delivery system by harvesting energy from the leaf motion in wind

Smart agriculture tools as well as advanced studies on agrochemicals and plant biostimulants aim to improve crop productivity and more efficient use of resources without sacrificing sustainability. Recently, multiple advanced sensors for agricultural applications have been developed, however much less advancement is reported in the field of precise delivery of agriculture chemicals. The organic electronic ion pump (OEIP) enables electrophoretically-controlled delivery of ionic molecules in the plant tissue, however it needs external power-supplies complicating its application in the field. Here, we demonstrate that an OEIP can be powered by wind-driven leaf motion through contact electrification between a natural leaf and an artificial leaf. This plant-hybrid triboelectric nanogenerator (TENG) directly charges the OEIP, enabling proton delivery into a pH indicator solution, which triggers visible color changes as a proof-of-concept. The successful delivery of up to 44 nmol of protons was revealed by pH measurements after 17 h autonomous operation in air flow moving the plant and artificial leaves. Several control tests indicated that the proton delivery was powered uniquely by the charges generated during leaf fluttering. The OEIP-TENG combination opens the potential for targeted and self-powered long-term delivery of relevant chemicals in plants, with the possibility of enhancing growth and resistance to abiotic stressors.

Integrating Single-Cell RNA-Seq and ATAC-Seq Analysis Reveals Uterine Cell Heterogeneity and Regulatory Networks Linked to Pimpled Eggs in Chickens.

Pimpled eggs have defective shells, which severely impacts hatching rates and transportation safety. In this study, we constructed single-cell resolution transcriptomic and chromatin accessibility maps from uterine tissues of chickens using single-cell RNA sequencing (scRNA-seq) and single-cell ATAC sequencing (scATAC-seq). We identified 11 major cell types and characterized their marker genes, along with specific transcription factors (TFs) that determine cell fate. CellChat analysis showed that fibroblasts had the most extensive intercellular communication network and that the chickens laying pimpled eggs had amplified immune-related signaling pathways. Differential expression and enrichment analyses indicated that inflammation in pimpled egg-laying chickens may lead to disruptions in their circadian rhythm and changes in the expression of ion transport-related genes, which negatively impacts eggshell quality. We then integrated TF analysis to construct a regulatory network involving TF-target gene-Gene Ontology associations related to pimpled eggs. We found that the transcription factors ATF3, ATF4, JUN, and FOS regulate uterine activities upstream, while the downregulation of ion pumps and genes associated with metal ion binding directly promotes the formation of pimpled eggs. Finally, by integrating the results of scRNA-seq and scATAC-seq, we identified a rare cell type-ionocytes. Our study constructed single-cell resolution transcriptomic and chromatin accessibility maps of chicken uterine tissue and explored the molecular regulatory mechanisms underlying pimpled egg formation. Our findings provide deeper insights into the structure and function of the chicken uterus, as well as the molecular mechanisms of eggshell formation.

Oxidative stress and chronic cerebral hypoperfusion: An overview from preclinical rodent models.

Chronic cerebral hypoperfusion (CCH) is an important clinical condition characterized by a prolonged reduction in cerebral blood flow that contributes to several neurodegenerative diseases, including vascular dementia and Alzheimer's disease. A number of rodent models of CCH have been developed that mimic the human pathological conditions of reduced cerebral perfusion. These models have been instrumental in elucidating the molecular and cellular mechanisms involved in CCH-induced brain damage. Oxidative stress is induced by perturbations in cellular pathways caused by CCH, including mitochondrial dysfunction, ion pump dysfunction, and adenosine triphosphate (ATP) depletion. The deleterious stress leads to the accumulation of reactive oxygen species (ROS) and exacerbates damage to neuronal structures, significantly impairing cognitive function. Among the various therapeutic strategies being evaluated, edaravone, a potent antioxidant, is emerging as a promising drug due to its neuroprotective properties against oxidative stress. Initially approved for use in ischemic stroke, research using rodent CCH models has shown that edaravone has significant efficacy in scavenging free radicals and ameliorating oxidative stress-induced neuronal damage under CCH conditions. This mini-review summarizes the current literature on the rodent models of CCH and then discusses the therapeutic potential of edaravone to reduce neuronal and vascular damage caused by CCH-induced oxidative stress.

Bioinspired Ionic Elastomer with Skin‐Like Piezo‐Ionic Dynamics Enabled by a Self‐Confined Multi‐Interaction Network

AbstractSoft ionic elastomers have attracted considerable research interest in mimicking the multiple functions of human skin. However, these ionic elastomers struggle to simultaneously achieve controllable ion dynamics and other essential performance, such as self‐healing ability and appropriate mechanical robustness. Herein, bioinspired by Piezo proteins and integrins in human skin, thioctic acid (TA)‐derived ionic elastomers with skin‐like piezo‐ionic dynamics are fabricated via a multi‐confined interaction network. This bionic network is constructed by introducing a diene comonomer and lithium salt filler into polysulfides (poly (TA)), generating many dynamic interactions (various hydrogen bonds and lithium bonds). These dynamic interactions can bind ions to the polysulfides and be destroyed under external pressure stimulation, achieving controllable ion pumping behavior. This unique design concept enables these ionic elastomers to selectively respond to pressure (the optimal sample exhibits 152 times signal intensity with a sensitivity of 49.53‐1.13 kPa−1), along with leak prevention, recyclability, and degradability. Besides, these interactions also serve as sacrificial bonds and self‐healing sites to synergistically enhance all aspects of performance, yielding a high modulus of 2.47 MPa and outstanding self‐healing efficiency of 98%. It is believed that this work could create a new approach for utilizing sustainable materials in next‐generation “green” flexible sensors.

Towards Clinical Application: Calcium Waves for In Vitro Qualitative Assessment of Propagated Primary Human Corneal Endothelial Cells.

Corneal endothelium cells (CECs) regulate corneal hydration between the leaky barrier of the corneal endothelium and the ionic pumps on the surface of CECs. As CECs do not regenerate, loss of CECs leads to poor vision and corneal blindness. Corneal transplant is the only treatment option; however, there is a severe shortage of donor corneas globally. Cell therapy using propagated primary human CECs is an alternative approach to corneal transplantations, and proof of functionality is crucial for validating such CECs. Expression markers like Na-K-ATPase and ZO-1 are typical but not specific to CECs. Assessing the barrier function of the expanded CECs via electrical resistance (i.e., TEER and Ussing's chamber) involves difficult techniques and is thus impractical for clinical application. Calcium has been demonstrated to affect the paracellular permeability of the corneal endothelium. Its absence alters morphology and disrupts apical junctions in bovine CECs, underscoring its importance. Calcium signaling patterns such as calcium waves affect the rate of wound healing in bovine CECs. Therefore, observing calcium waves in expanded CECs could provide valuable insights into their health and functional integrity. Mechanical or chemical stimulations, combined with Ca2+-sensitive fluorescent dyes and time-lapse imaging, can be used to visualize these waves, which could potentially be used to qualify expanded CECs.

Structural Insight on the Selectivity of Calyx[4]Arene-Based Inhibitors of Mg2+-Dependent Atp-Hydrolases.

Located in plasma membranes, ATP hydrolases are involved in several dynamic transport processes, helping to control the movement of ions across cell membranes. ATP hydrolase acts as a transport protein, converting energy from ATP hydrolysis into transport molecules against their concentration gradients. In addition to energy metabolism and active transport, ATP hydrolase is essential for maintaining cellular homeostasis and cell function. This study focused on the domain architecture model of P-type ATPases, which participate in the reaction cycles of ATP hydrolysis carried out by membrane transport systems - Na+, K+-ATPase and Ca2+, Mg2+-ATPase. Targeted modulation of Na+, K+-ATPase and Ca2+, Mg2+-ATPase by unnatural drugs is of greatest interest due to the lack of known effectors. This new discovery presents a convenient model based on our recent experimental studies of the membrane structures and myocytes of the uterine smooth muscle, the myometrium. This current study strongly supports the fact that nanosized calix[4]arenes functionalised on the upper rings of the macrocycle with biologically active phosphonic acid fragments can serve as selective and potent inhibitors of cation-transporting electroenzymes. This is how we discovered that calix[4]arene of methylenebisphosphonic acid C-97 and calix[4]arene of bis-aminophosphonic acid C-107 selectively and effectively (I0.5 <100 nM) inhibit the activity of Mg2+, ATP-dependent electrogenic Na+ K+ plasma membrane pump. As drug discovery in the field of Mg2+-ATPase inhibitors is uncharted territory, basic research holds the key to explaining and predicting the mechanism of interaction and action of different classes of compounds. In light of the presented results, new calix[4]arene compounds can be used as potent inhibitors of Mg2+, ATP-dependent electrogenic ion pumps.

Covalent labeling of the Arabidopsis plasma membrane H+-ATPase reveals 3D conformational changes involving the C-terminal regulatory domain.

The plasma membrane proton pump is the primary energy transducing, electrogenic ion pump of the plasma membrane in plants and fungi. Compared to its fungal counterpart, the plant plasma membrane proton pump's regulatory C-terminal domain (CTD) contains an additional regulatory segment that links multiple sensory pathways regulating plant cell length through phosphorylation and recruitment of regulatory 14-3-3 proteins. However, a complete structural model of a plant proton pump is lacking. Here, we performed covalent labeling with mass spectrometric analysis (CL-MS) on the Arabidopsis pump AHA2 to identify potential interactions between the CTD and the catalytic domains. Our results suggest that autoinhibition in the plant enzyme is much more structurally complex than in the fungal enzyme.

Efficient Light-Driven Ion Pumping for Deep Desalination via the Vertical Gradient Protonation of Covalent Organic Framework Membranes.

Traditional desalination methods face criticism due to high energy requirements and inadequate trace ion removal, whereas natural light-driven ion pumps offer superior efficiency. Current synthetic systems are constrained by short exciton lifetimes, which limit their ability to generate sufficient electric fields for effective ion pumping. We introduce an innovative approach utilizing covalent-organic framework membranes that enhance light absorption and reduce charge recombination through vertical gradient protonation of imine linkages during acid-catalyzed liquid-liquid interfacial polymerization. This technique creates intralayer and interlayer heterojunctions, facilitating interlayer hybridization and establishing a robust built-in electric field under illumination. These improvements enable the membranes to achieve remarkable ion transport across extreme concentration gradients (2000:1), with a transport rate of approximately 3.2 × 1012 ions per second per square centimeter and reduce ion concentrations to parts per billion. This performance significantly surpasses that of conventional reverse osmosis systems, representing a major advancement in solar-powered desalination technology by substantially reducing energy consumption and secondary waste.

Investigation of Hydrogen Isotope Conductivity through Single- and Multi-Layer Graphene

Since its discovery, the outstanding properties of graphene regarding electrical and thermal conductivity as well as mechanical stability have increased the interest of the scientific community in this versatile material. The intensive investigations on the material uncovered even more unique properties that were previously thought to be physically impossible. In 2014 Hu et al. had shown that pristine graphene, which was prior thought to be an impermeable barrier, could be penetrated by ions.[1] Especially ions of hydrogen isotopes seem to be able to penetrate graphene at a fast rate. This permeation is supposed to cause a separation where protium passes more easily than the other isotopes which is still thoroughly discussed in recent literature. Contrary to single layer graphene, the permeability through multiple layers of graphene as an A-B-stacking seems to be less discussed nor investigated. Theoretical calculations of Eren et al. proposed a possible and fast interstitial movement of ions through multi-layered 2D-materials.[2] Within this work we were able to prove that in fact, several layers of graphene could be penetrated by protons and deuterons. By utilizing impedance spectroscopy, it was possible to show that the ions pass through the graphene layers. The currents produced in this electrochemical ion pump exceeded 500 mA/cm2 and showed that the graphene added almost no additional resistance. Combining impedance spectroscopy with mass spectrometry, we were also able to analyze whether isotope separation occurred for protons and deuterons. With electrochemical measurements we validated conduction of ions through graphene but were unable to find any separation. Therefore, our results are challenging a lot of recent results in this field.

Visualizing Single V-ATPase Rotation Using Janus Nanoparticles.

Understanding the function of rotary molecular motors, such as rotary ATPases, relies on our ability to visualize single-molecule rotation. Traditional imaging methods often involve tagging those motors with nanoparticles (NPs) and inferring their rotation from the translational motion of NPs. Here, we report an approach using "two-faced" Janus NPs to directly image the rotation of a single V-ATPase from Enterococcus hirae, an ATP-driven rotary ion pump. By employing a 500 nm silica/gold Janus NP, we exploit its asymmetric optical contrast, a silica core with a gold cap on one hemisphere, to achieve precise imaging of the unidirectional counterclockwise rotation of single V-ATPase motors immobilized on surfaces. Despite the added viscous load from the relatively large Janus NP probe, our approach provides accurate torque measurements of a single V-ATPase. This study underscores the advantages of Janus NPs over conventional probes, establishing them as powerful tools for the single-molecule analysis of rotary molecular motors.