Proton Pump Research Articles

Peroral endoscopic myotomy is an effective treatment for achalasia combined with hiatal hernia.

To explore the feasibility of peroral endoscopic myotomy (POEM) in patients with achalasia and hiatal hernia. We performed a retrospective review of 2136 patients with achalasia between January 2016 and December 2022. Patients with achalasia and hiatal hernia were assigned into study group, and matched patients with achalasia but no hiatal hernia were assigned into control group. The preoperative baseline information, procedure-related adverse events (AEs) and follow-up data were compared between the two groups. Hiatal hernia was identified in 56/1564 (3.6%) patients with achalasia. All of these patients underwent POEM with success. The preoperative baseline characteristics were similar between the study and control group. The study group presented with a similar rate of mucosal injury (12.5% vs 16.1, P = 0.589), pneumothorax (3.6% vs 1.8%, P = 1.000), pleural effusion (8.9% vs 12.5%, P = 0.541) and major AEs (1.8% vs 1.8%, P = 1.000) compared with the control group. As for the follow-up data, no significant differences were observed in clinical success (96.4% vs 92.9%, P = 0.679; 93.6% vs 94.0%, P = 1.000; 86.5% vs 91.4%, P = 0.711) clinical reflux (25.0% vs 19.6%, P = 0.496; 31.9% vs 26.0%, P = 0.521; 35.1% vs 31.4%, P = 0.739) and proton pump inhibitor usage (17.9% vs 16.1%, P = 0.801; 29.8% vs 24.0%, P = 0.520; 32.4% vs 25.7%, P = 0.531) between the study group and control group at 1-year, 2-year and 3-year follow-ups. POEM is a safe and effective treatment for achalasia combined with hiatal hernia.

Society of Critical Care Medicine and American Society of Health-System Pharmacists Guideline for the Prevention of Stress-Related Gastrointestinal Bleeding in Critically Ill Adults.

Critically ill adults can develop stress-related mucosal damage from gastrointestinal hypoperfusion and reperfusion injury, predisposing them to clinically important stress-related upper gastrointestinal bleeding (UGIB). The objective of this guideline was to develop evidence-based recommendations for the prevention of UGIB in adults in the ICU. A multiprofessional panel of 18 international experts from dietetics, critical care medicine, nursing, and pharmacy, and two methodologists developed evidence-based recommendations in alignment with the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology. Conflict-of-interest policies were strictly followed during all phases of guideline development including task force selection and voting. The panel members identified and formulated 13 Population, Intervention, Comparison, and Outcome questions. We conducted a systematic review for each question to identify the best available evidence, statistically analyzed the evidence, and then assessed the certainty of the evidence using the GRADE approach. We used the evidence-to-decision framework to formulate the recommendations. Good practice statements were included to provide additional guidance. The panel generated nine conditional recommendations and made four good practice statements. Factors that likely increase the risk for clinically important stress-related UGIB in critically ill adults include coagulopathy, shock, and chronic liver disease. There is no firm evidence for mechanical ventilation alone being a risk factor. Enteral nutrition probably reduces UGIB risk. All critically ill adults with factors that likely increase the risk for stress-related UGIB should receive either proton pump inhibitors or histamine-2 receptor antagonists, at low dosage regimens, to prevent UGIB. Prophylaxis should be discontinued when critical illness is no longer evident or the risk factor(s) is no longer present despite ongoing critical illness. Discontinuation of stress ulcer prophylaxis before transfer out of the ICU is necessary to prevent inappropriate prescribing. The guideline panel achieved consensus regarding the recommendations for the prevention of stress-related UGIB. These recommendations are intended for consideration along with the patient's existing clinical status.

Association Between Proton Pump Inhibitors and the Risk of Intestinal Behçet's Disease.

This study aimed to investigate the association between proton pump inhibitor (PPI) use and the incidence of intestinal Behçet's disease (BD) in patients with BD. A retrospective cohort study was conducted at the University of Tokyo Hospital, including BD patients diagnosed between April 2005 and November 2023. Cox models and Kaplan-Meier analyses were utilized to evaluate hazard ratios (HRs) and cumulative incidence of intestinal BD, respectively. Secondary analyses were performed to assess the duration and dose-response relationship of PPI use. Among 194 BD patients, 25.3% developed intestinal BD during a mean followup of 12 years. PPI users exhibited a significantly higher incidence of intestinal BD compared to non-users (adjusted HR 2.48, 95% CI 1.38-4.47, P = 0.0024), with a confirmed duration/dose-dependent relationship. The cumulative incidence of intestinal BD was markedly elevated in PPI users (Log rank P < 0.001). The result was similar to that in the Propensity score-matched cohort. The study demonstrates a significant association between PPI use and increased incidence of intestinal BD in BD patients. Caution in prescribing PPIs for BD patients is warranted due to the potential risk of severe complications associated with intestinal BD.

Review article: Oesophageal disorders in chronic liver disease.

Oesophageal disorders and chronic liver disease are common worldwide and significantly impact quality of life. The intricate link between these conditions, including how oesophageal disorders like GERD, Barrett's oesophagus and oesophageal cancer affect and are affected by chronic liver disease, remains poorly understood. To review the relationship between oesophageal disorders and chronic liver disease, evaluating epidemiology, pathophysiology and therapeutic factors. We reviewed the literature on the relationship between oesophageal disorders and chronic liver disease, including cirrhosis, using the PubMed database RESULTS: Oesophageal disorders such as gastroesophageal reflux disease, Barrett's oesophagus, oesophageal cancer, oesophageal motor disorders and oesophageal candidiasis are prevalent among individuals with cirrhosis, exacerbating the burden of liver disease. These diseases have a multifaceted symptomatology and pathogenic basis, posing a significant challenge in cirrhotic patients that necessitates careful diagnosis and management. Additionally, therapies frequently used for these diseases, such as proton pump inhibitors, require careful consideration in cirrhotic patients due to potential adverse effects and altered pharmacokinetics. Managing oesophageal disorders in cirrhotic patients requires a cautious approach due to possible interactions with medications and the risk of adverse effects. Furthermore, symptoms associated with these conditions are often exacerbated by common interventions in patients with cirrhosis, such as band ligation for oesophageal varices. Oesophageal disorders are common in cirrhosis and increase the disease burden. These conditions require careful management due to complex symptoms and treatment risks. Proton pump inhibitors and other therapies must be used cautiously, as cirrhosis interventions can worsen symptoms.

Modern Management of Gastric Neuroendocrine Neoplasms.

Gastric neuroendocrine neoplasms (G-NENs) are a heterogeneous group of tumors that broadly fall into two groups. The first group, driven by oversecretion of gastrin, are generally multifocal, small, and behave indolently with a low (but non-zero) risk of progression and metastatic spread. They are conventionally categorized into type 1, with endogenous gastric-based overproduction of gastrin, and type 2 G-NEN, with overproduction of gastrin from an extra-gastric gastrin-secreting tumor. The second group, termed type 3 G-NEN, occur spontaneously and are potentially more aggressive, having a clinical course analogous to other neuroendocrine tumors of the gastrointestinal tract. Type 1 G-NEN can be managed with endoscopic surveillance and resection of visible lesions with great success, reserving surgery for the rare high-risk lesion, whereas surgical resection of the causative gastrin-secreting tumor in type 2 G-NEN is usually curative. Type 3 G-NEN is usually managed with formal surgical resection but there is growing evidence that limited surgery or even endoscopic resection in appropriately selected patients with low risk is both safe and effective. A novel subtype of G-NEN, associated with long-term proton pump inhibitor usage, is increasing in incidence. The pathophysiology seems to parallel type 1 G-NEN. In the setting of metastatic disease, which can occur in any subtype but is most common by far in type 3 G-NEN, the lack of trial data unique to G-NEN results in extrapolation of strategies and agents for treatment of non-gastric neuroendocrine disease. The rapid pace of development in this area is likely to benefit the metastatic G-NEN patient as well. As treatment is predicate on type of G-NEN, establishing the etiology of the lesion is crucial but growing knowledge of G-NEN pathophysiology and close collaboration between pathologists, gastroenterologists, radiologists, surgeons, and oncologists have enabled a growing trend towards de-escalation and less-invasive treatment paradigms.

Vitamin B12 (cobalamin) deficiency in gastroenterological diseases - review

Introduction: Vitamin B12 is a water-soluble vitamin found primarily in animal-derived products such as red meat, dairy, and eggs. An essential substance for its absorption is the intrinsic factor, produced by the parietal cells of the stomach. After absorption in the distal ileum, cobalamin acts as a coenzyme in DNA synthesis and the metabolism of fatty acids and homocysteine. In addition to its well-known influence on the nervous system, it has been associated with gastrointestinal diseases according to numerous authors. Objective: The objective of this study is to gather and analyze literature regarding the associations between vitamin B12 deficiency and gastrointestinal diseases, including gastroesophageal reflux disease (GERD), gastritis, inflammatory bowel disease (IBD), small intestinal bacterial overgrowth (SIBO), and hepatitis C (HCV). Materials and Methods: A literature review was conducted using the PubMed database with the following search terms: vitamin B12, cobalamin, deficiency, gastrointestinal diseases, GERD, IBD, SIBO, HCV. Current Knowledge: Vitamin B12 deficiency can be caused by autoimmune factors, dietary insufficiencies, toxin exposure, and malabsorption disorders related to gastrointestinal diseases. Gastrointestinal conditions such as GERD and IBD can both lead to and be exacerbated by cobalamin deficiency. Furthermore, vitamin B12 deficiency may be worsened by prolonged use of proton pump inhibitors (PPIs) and Helicobacter pylori infection. Conclusions: An adequate amount of vitamin B12 is crucial for gastrointestinal health. Deficiency can significantly impact the course and symptoms of many gastrointestinal diseases. Therefore, monitoring and supplementation of vitamin B12 should be an integral part of managing patients with gastrointestinal conditions.

Construction of Sulfonated Carbon Nanoflowers for Efficient Proton Transportation of the Proton Exchange Membrane

Construction of Sulfonated Carbon Nanoflowers for Efficient Proton Transportation of the Proton Exchange Membrane

Dimerization is required for the glycosylation of S1-S2 linker of sea urchin voltage-gated proton channel Hv1

Multimerization of ion channels is essential for establishing the ion-selective pathway and tuning the gating regulated by membrane potential, second messengers, and temperature. Voltage-gated proton channel, Hv1, consists of voltage-sensor domain (VSD) and coiled-coil domain. Hv1 forms dimer, whereas voltage-dependent channel activity is self-contained in monomer unlike many ion channels, which assemble to form ion conductive pathways among multiple subunits. Dimerization of Hv1 is necessary for cooperative gating, but other roles of dimerization in physiological aspects are still largely unclear. In this study, we show that dimerization of Hv1 takes place in ER. Sea urchin Hv1 (Strongylocentrotus purpuratus Hv1: SpHv1) was glycosylated in the consensus sequence for N-linked glycosylation within the S1-S2 extracellular loop. However, glycosylation was not observed in the monomeric SpHv1 that lacks the coiled-coil domain. A version of mHv1 in which the S1-S2 loop was replaced by that of SpHv1 showed glycosylation and its monomeric form was not glycosylated. Tandem dimer of monomeric SpHv1 underwent glycosylation, suggesting that dimerization of Hv1 is required for glycosylation. Moreover, when monomeric Hv1 has a dilysine motif in the C-terminal end, which is known to act as a retrieval signal from Golgi to ER, prolonging the time of residency in ER, it was glycosylated. Overall, our results suggest that monomeric SpHv1 does not stay long in ER, thereby escaping glycosylation, while the dimerization causes the proteins to stay longer in ER. Thus, the findings highlight the novel significance of dimerization of Hv1: regulation of biogenesis and maturation of the proteins in intracellular compartments.

The association of systemic condition and medications on alveolar bone loss and tooth attrition.

Periodontal disease is caused by subgingival bacteria that adversely affect the host immune system and create and maintain unmitigated inflammation in gingival and periodontal tissues. The condition is also linked to systemic conditions including cardiovascular disease, diabetes, and arthritis. Periodontitis elevates the bacterial load and spreads systemic inflammation through infection and inflammation. The main radiographic sign of periodontitis is marginal bone loss. Risk factors, including medications, smoking, age, and gender, are known to influence periodontal health. However, there is little information about the impact of systemic conditions, and medications on tooth wear. To assess the association between systemic conditions and medications and radiographic signs of tooth wear (TW) and marginal bone loss (MBL) . This retrospective analysis was conducted on a group of 2223 consecutive patients who came for dental treatment in the clinics of a large HMO in Israel. Data available for the study included details of concomitant systemic diseases and medication and full-mouth radiographic surveys. Odds ratio and logistic regression analysis were used to detect associations between systemic conditions and medication, and MBL and TW . The results indicated an elevated odds ratio for TW associated with age, gender, and smoking across all age groups. Among young patients, those using proton pump inhibitors and psychiatric medications had an elevated risk of TW. Age, smoking, and diabetes conditions were associated with an increased odds ratio for MBL in all age groups. Psychiatric medications and gender elevated the odds ratio for MBL only among older patients. Our results highlight the significant impact of age, gender, and smoking on tooth wear and extend these risks to alveolar bone loss when combined with diabetes and psychiatric conditions.

Treatment Response With Potassium-competitive Acid Blockers Based on Clinical Phenotypes of Gastroesophageal Reflux Disease: A Systematic Literature Review and Meta-analysis.

Gastroesophageal reflux disease (GERD) is typically managed based on the clinical phenotype. We evaluated the efficacy and safety of potassium-competitive acid blockers (PCABs) in patients with various clinical GERD phenotypes. Core databases were searched for studies comparing PCABs and proton pump inhibitors (PPIs) in clinical GERD phenotypes of erosive reflux disease (ERD), non-erosive reflux disease (NERD), PPI-resistant GERD and night-time heartburn. Additional analysis was performed based on disease severity and drug dosage, and pooled efficacy was calculated. In 9 randomized controlled trials (RCTs) evaluating the initial treatment of ERD, the risk ratio for healing with PCABs versus PPIs was 1.09 (95% CI, 1.04-1.13) at 2 weeks and 1.03 (95% CI, 1.00-1.07) at 8 weeks, respectively. PCABs exhibited a significant increase in both initial and sustained healing of ERD compared to PPIs in RCTs, driven particularly in severe ERD (Los Angeles grade C/D). In 3 NERD RCTs, PCAB was superior to placebo in proportion of days without heartburn. Observational studies on PPI-resistant symptomatic GERD reported symptom frequency improvement in 86.3% of patients, while 90.7% showed improvement in PPIresistant ERD across 5 observational studies. Two RCTs for night-time heartburn had different endpoints, limiting meta-analysis. Pronounced hypergastrinemia was observed in patients treated with PCABs. Compared to PPIs, PCABs have superior efficacy and faster therapeutic effect in the initial and maintenance therapy of ERD, particularly severe ERD. While PCABs may be an alternative treatment option in NERD and PPI-resistant GERD, findings were inconclusive in patients with night-time heartburn.

Concomitant Medications Alter Clinical Outcomes in Patients with Advanced Digestive Tract Cancer Receiving PD-1 Checkpoint Inhibitors Combined with Antiangiogenetic Agents.

Our study aimed to evaluate the impact of concomitant medications on the response and survival of patients with advanced digestive tract cancer receiving an immunotherapy-antiangiogenesis combination. We conducted a three-center observational retrospective study of patients with advanced digestive tract cancer who received programmed death-1 (PD-1) inhibitors plus antiangiogenic agents between March 2019 and July 2022 in China. The patients had one of the three types of primary tumors: hepatocellular carcinoma (HCC), colorectal cancer (CRC), and gastric cancer (GC). The study included 352 patients. The most frequently prescribed co-medications were nonsteroidal anti-inflammatory drugs (NSAIDs) (46.3%), proton pump inhibitors (PPIs) (38.0%), systemic antibiotics (33.8%), and corticosteroids (30.1%). Probiotics had a direct correlation with a higher objective response rate (ORR) (OR 2.4, 95% CI 1.2 to 4.7, p = 0.013). Patients who received PPIs for gastritis/gastroesophageal reflux disease (GERD) (HR 0.7, 95% CI 0.5 to 1.0, p = 0.045), anticoagulants (HR 0.5, 95% CI 0.3 to 0.9, p = 0.009), and probiotics (HR 0.7, 95% CI 0.5 to 1.0, p = 0.034) had longer progression-free survival (PFS). Patients who received PPIs for gastritis/GERD (HR 0.6, 95% CI 0.4 to 0.9; p = 0.009) had longer overall survival (OS), while patients receiving opioids (HR 1.5, 95% CI 1.1 to 2.0, p = 0.010) had a significantly higher risk of death. Patients with advanced digestive tract cancer who were administered PPIs for gastritis/GERD indication, anticoagulants, or probiotics in combination with PD-1 inhibitors and antiangiogenic agents experienced improved clinical outcomes. However, opioid administration was linked to reduced OS in patients receiving combined therapy.

A Review on the Pharmacokinetics and Toxicological Profile of Rabeprazole

Rabeprazole, a proton pump inhibitor, is used for individuals with ulcers. The prodrug is transformed into an active sulphenamide form by the acidic conditions present in the parietal cells. Rabeprazole inhibits the H+K+ ATPase of the gastric cells, leading to a decrease in the generation of stomach acid in both normal and stimulated situations. The present review was based on the pharmacokinetics and toxicological profile of Rabeprazole. Once absorbed into the body, approximately 96.3–97% of rabeprazole is bound to plasma proteins. In humans, the half-life of rabeprazole is approximately one hour. The peak concentration of rabeprazole in human plasma following a single oral dose does not appear until around 3.5 hours later. Rabeprazole is metabolised mostly by the liver. Once the liver has metabolised the medicine, 90% of it will be excreted via the kidneys. The elimination fraction is 10%. Rabeprazole is mostly metabolised by the cytochrome P450 enzymes CYP2C19 and CYP3A4. . It concluded that in the human pylorus, it decreased muscular tone, maximal contraction values, and contraction frequencies. When diclofenac sodium SR, glucosamine, diacerein, calcium, and vitamin D preparations were administered in addition to rabeprazole, the patients experienced GI bleeding, fatty liver grade 1, mild epigastric discomfort, black stools, and decreased haemoglobin content.

Hyphae of the fungus Aspergillus nidulans demonstrate chemotropism to nutrients and pH.

The importance of fungi in ecological systems and pathogenicity hinges on their ability to search for nutrients, substrates, and hosts. Despite this, the question of whether fungal hyphae exhibit chemotropism toward them remains largely unresolved and requires close examination at the cellular level. Here, we designed a microfluidic device to assess hyphal chemotropism of Aspergillus nidulans in response to carbon and nitrogen sources, as well as pH. Within this device, hyphae could determine their growth direction in a two-layer flow with distinct compositions that were adjacent but non-mixing. Under conditions with and without a carbon source, hyphae changed growth direction to remain in the presence of a carbon source, but it was still difficult to distinguish between differences in growth and chemotropism. Although nitrogen sources such as ammonia and nitrate are important for growth, the hyphae indicated negative chemotropism to avoid them depending on the specific transporters. This fungus grows equally well at the colony level in the pH range of 4 to 9, but the hyphae exhibited chemotropism to acidic pH. The proton pump PmaA is vital for the chemotropism to acid pH, while the master regulatory for pH adaptation PacC is not involved, suggesting that chemotropism and adaptive growth via gene expression regulation are distinct regulatory mechanisms. Despite various plasma membrane transporters are distributed across membranes except at the hyphal tip, the control of growth direction occurs at the tip. Finally, we explored the mechanisms linking these two phenomena, tip growth and chemotropism.

Treatment Response With Potassium-competitive Acid Blockers Based on Clinical Phenotypes of Gastroesophageal Reflux Disease: A Systematic Literature Review and Meta-analysis.

Gastroesophageal reflux disease (GERD) is typically managed based on the clinical phenotype. We evaluated the efficacy and safety of potassium-competitive acid blockers (PCABs) in patients with various clinical GERD phenotypes. Core databases were searched for studies comparing PCABs and proton pump inhibitors (PPIs) in clinical GERD phenotypes of erosive reflux disease (ERD), non-erosive reflux disease (NERD), PPI-resistant GERD and night-time heartburn. Additional analysis was performed based on disease severity and drug dosage, and pooled efficacy was calculated. In 9 randomized controlled trials (RCTs) evaluating the initial treatment of ERD, the risk ratio for healing with PCABs versus PPIs was 1.09 (95% CI, 1.04-1.13) at 2 weeks and 1.03 (95% CI, 1.00-1.07) at 8 weeks, respectively. PCABs exhibited a significant increase in both initial and sustained healing of ERD compared to PPIs in RCTs, driven particularly in severe ERD (Los Angeles grade C/D). In 3 NERD RCTs, PCAB was superior to placebo in proportion of days without heartburn. Observational studies on PPI-resistant symptomatic GERD reported symptom frequency improvement in 86.3% of patients, while 90.7% showed improvement in PPIresistant ERD across 5 observational studies. Two RCTs for night-time heartburn had different endpoints, limiting meta-analysis. Pronounced hypergastrinemia was observed in patients treated with PCABs. Compared to PPIs, PCABs have superior efficacy and faster therapeutic effect in the initial and maintenance therapy of ERD, particularly severe ERD. While PCABs may be an alternative treatment option in NERD and PPI-resistant GERD, findings were inconclusive in patients with night-time heartburn.

Functionality of the V-type ATPase during asexual growth and development of Plasmodium falciparum

V-type ATPases are highly conserved hetero-multi-subunit proton pumping machineries found in all eukaryotes. They utilize ATP hydrolysis to pump protons, acidifying intracellular or extracellular compartments, and are thus crucial for various biological processes. Despite their evolutionary conservation in malaria parasites, this proton pump remains understudied. To understand the localization and biological functions of Plasmodium falciparum V-type ATPase, we employed CRISPR/Cas9 to endogenously tag the subunit A of the V1 domain. V1A (PF3D7_1311900) was tagged with a triple hemagglutinin epitope and the TetR-DOZI-aptamer system for conditional expression under the regulation of anhydrotetracycline. Via immunofluorescence assays, we identified that V-type ATPase is expressed throughout the intraerythrocytic developmental cycle and is mainly localized on the digestive vacuole and parasite plasma membrane. Immuno-electron microscopy further revealed that V-type ATPase is also localized on secretory organelles in merozoites. Knockdown of V1A led to cytosolic pH imbalance and blockage of hemoglobin digestion in the digestive vacuole, resulting in an arrest of parasite development in the trophozoite stage and, ultimately, parasite demise. Using Bafilomycin A1, a specific inhibitor of V-type ATPases, we found that the P. falciparum V-type ATPase is likely involved in parasite invasion but is not critical for ring stage development. Further, we detected a large molecular weight complex in BN-PAGE (∼ 1.0 MDa), corresponding to the total molecular weights of V1 and Vo domains. Together, we show that V-type ATPase is localized on multiple subcellular compartments in P. falciparum, and its functionality throughout the asexual cycle varies depending on the parasite developmental stages.

Efficacy and Safety of Potassium-competitive Acid Blockers Versus Proton Pump Inhibitors for Peptic Ulcer Disease or Post-Procedural Artificial Ulcers: A Systematic Review and Meta-Analysis.

Peptic ulcer disease (PUD) and post-procedural artificial ulcers are common ulcer disease. For them, Proton pump inhibitor (PPI) and potassium-competitive acid blocker (P-CAB) are commonly used in clinical practice. PPI requires acid, time, and multiple doses, but P-CAB has fewer limitations. We compared the efficacy, safety and prevention of PPI and P-CAB in PUD and artificial ulcer. We searched PubMed, ClinicalTrials.gov, Embase, Cochrane Library, and Web of Science databases for all studies. All eligible randomized controlled trials up to August 5, 2023 were included. Healing rates, shrinking rates, treatment-emergent adverse events rates and recurrence rates were measured. Risk of bias, sensitivity analyses, and heterogeneity were also performed. 20 researches which were selected from 926 screening studies and in total 6567 participants were included. The risk ratio (RR) of healing rate with P-CABs versus PPIs of PUD at 4-week was RR 1.01 (95% CI 0.98-1.04). In addition, the healing rate distinction of artificial peptic ulcer was RR 1.04 (0.89-1.22), and the shrinking rate was MD 0.10 (-1.30-1.51). The result of TEAEs rate of PUD was RR 1.11 (0.91-1.35) and the delayed bleeding rate of artificial ulcer was RR 0.35 (0.16-0.80). The RR for recurrence rate of drug-related ulcers was 0.45 (0.25-0.81). P-CAB is non-inferior in healing artificial ulcer and conventional PUD, also the incidence of TEAEs. But there may be a statistical advantage in holding back delayed bleeding and preventing drug-induced ulcers. More standardized experiments are needed for further applications and more precise conclusions.

Single proton anti-freezing hydrogel electrolyte with enhanced ion migration number enabling high-performance supercapacitor

Compared with traditional binary ion electrolytes, single-ion electrolytes have higher ion migration number and can avoid concentration polarization. In this work, single proton hydrogel electrolytes were prepared by one-step free radical polymerization of acrylamide and 2-acrylaminoamido-2-methyl-1-propane sulfonic acid in ethylene glycol (EG)/water binary solvent. The electrolyte possesses good mechanical strength and excellent anti-freezing ability. A high conductivity of 1.28 mS cm−1 at −40 °C is achieved by adjusting monomer ratio and EG content. The proton hopping along the ion channel formed by the anionic polymer chain and the Grotthuss transport are responsible for the high conductivity. An extremely high ion migration number of 0.87 is obtained. The fixed anionic group endows the hydrogel electrolyte with good anticorrosion ability. The hydrogel electrolyte assembled supercapacitor (SC) exhibits excellent electrochemical performance in a wide temperature range from −40 °C to 60 °C and can be stored at −30 °C for 10 months without capacitance attenuation. The capacitance retention rate of the SC is as high as 92% after 15,000 cycles at both room temperature and − 40 °C. The single proton hydrogel electrolyte provides a new route for the further development of storage device based proton transport.

Assessing the mechanism of facilitated proton transport across GUVs trapped in a microfluidic device

Proton transport across lipid membranes is one of the most fundamental reactions that make up living organisms. In vitro, however, the study of proton transport reactions can be very challenging due to limitations imposed by proton concentrations, compartment size, and unstirred layers as well as buffer exchange and buffer capacity. In this study, we have developed a proton permeation assay based on the microfluidic trapping of giant vesicles enclosing the pH-sensitive dye pyranine to address some of these challenges. Time-resolved fluorescence imaging upon a rapid pH shift enabled us to investigate the facilitated H+ permeation mediated by either a channel or a carrier. Specifically, we compared the proton transport rates as a function of different proton gradients of the channel gramicidin D and the proton carrier carbonyl cyanide-m-chlorophenyl hydrazone. Our results demonstrate the efficacy of the assay in monitoring proton transport reactions and distinguishing between a channel-like and a carrier-like mechanism. This groundbreaking result enabled us to elucidate the enigmatic mode of the proton permeation mechanism of the recently discovered natural fibupeptide lugdunin.

Activation of the influenza B M2 proton channel (BM2).

Influenza B viruses have co-circulated during most seasonal flu epidemics and can cause significant human morbidity and mortality due to their rapid mutation, emerging drug resistance, and severe impact on vulnerable populations. The influenza B M2 proton channel (BM2) plays an essential role in viral replication, but the mechanisms behind its symmetric proton conductance and the involvement of a second histidine (His27) cluster remain unclear. Here we perform the membrane- enabled continuous constant-pH molecular dynamics simulations on wildtype BM2 and a key H27A mutant to explore its pH-dependent conformational switch. Simulations capture the activation as the first histidine (His19) protonates and reveal the transition at lower pH values compared to AM2 is a result of electrostatic repulsions between His19 and pre-protonated His27. Crucially, we provide an atomic-level understanding of the symmetric proton conduction by identifying pre-activating channel hydration in the C-terminal portion. This research advances our understanding of the function of BM2 function and lays the groundwork for further chemically reactive modeling of the explicit proton transport process as well as possible anti-flu drug design efforts.

Highly acid-stable high-temperature proton exchange membrane: Azide-based polymeric ionic liquids for the enhancement of amino-polybenzimidazole

Polybenzimidazole (PBI) is commonly used for high-temperature proton exchange membranes. However, it is undeniably challenging for phosphoric acid (PA)-doped PBI membranes to have both high proton conductivity and excellent long-term stability. In this study, a series of polymer ionic liquid composite PBI membranes were fabricated. These membranes are made using two azide-functional ionic liquids and amino-polybenzimidazole, adjusting the amount of the two ionic liquids. The ionic pairs offered by the ionic liquids positively impact the transportation of protons and the stability of PA through the replacement of anions. It is noteworthy that crosslinked amino-polybenzimidazole membranes containing functional polymeric ionic liquids have proton conductivity of up to 131.7 mS cm−1 at 180 °C, and the PA retention after 240 h at 160 °C under humidity-free conditions is 86.5 %. In addition, the membrane is used in membrane electrodes with hydrogen and oxygen at the anode and cathode, respectively, exhibiting a peak power density of 694.6 mW cm−2 at 160 °C. And the voltage decay rate is 0.28 mV h−1 after long-term test. The findings indicate that membranes made of functional polymeric ionic liquids crosslinked with amino-polybenzimidazoleprovide a new strategy to enhance fuel cell durability.