Proton Pump Research Articles

Impact of concomitant prescriptions and lifestyle factors on the initial course of newly diagnosed inflammatory bowel disease

Introduction: There is a close relationship between the relapse of inflammatory bowel disease (IBD) and lifestyle factors, including concomitant medications such as non-steroidal anti-inflammatory drugs (NSAIDs), antithrombotic drugs, smoking status, and alcohol consumption. However, solid evidence is limited regarding the risk factors at diagnosis and initial disease course. This study aimed to explore the impact of concomitant prescriptions and lifestyle factors in patients with newly diagnosed IBD using a large-scale real-world database. Methods: This is a retrospective inception cohort study using the insurance claims database. Newly diagnosed patients with UC and CD were enrolled between January 2005 and May 2020. Concomitant prescriptions and lifestyle factors were assessed for new biologics use, surgery, and hospitalization during the first year. Results: In total, 6,743 patients with UC and 1,000 patients with CD were enrolled. Proton pump inhibitors, antithrombotics, antibiotics, and NSAIDs were identified as associated factors for both biologics use and hospitalization in UC patients (all p<0.01), and antithrombotics were identified as associated factors for both biologics use and hospitalization in CD patients (all p<0.01) in multivariable analyses. Interestingly, smoking was protective against hospitalization in UC patients (p<0.01), but not in CD patients (p=0.997), analyzed by univariate analysis. Alcohol consumption was protective against hospitalization outcomes in UC patients (p=0.02) but not in CD patients (p=0.27), analyzed by univariate analysis. Conclusion: Immediate attention should be paid to concomitant medications at diagnosis, because they may have impact on the initial course of IBD.

The biogeography of the mucosa-associated microbiome in health and disease.

Little is known about the biogeography of the mucosa associated microbiome (MAM) in patients with inflammatory bowel disease (IBD) versus controls in different segments of the gastrointestinal tract, as well as the links between the MAM, gastrointestinal symptoms, and use of proton pump inhibitors (PPI). We recruited 59 controls (without structural abnormalities and gastrointestinal symptoms), 44 patients with ulcerative colitis (UC) and 31 with Crohn's disease (CD). Biopsies from various segments of the upper and lower gastrointestinal tract were collected. Microbial composition was assessed via 16S rRNA gene amplicon analysis and the bacterial load of the mucosal biopsies were assessed via qPCR. The MAM was examined in the context of disease status, PPI usage, the severity of gastrointestinal symptoms, and the symptom response to a standardised nutrient challenge (SNC). Microbial communities of the MAM in the upper and lower gastrointestinal tract differed. IBD patients were characterised by relative and absolute depletion of numerous genera known to produce butyrate and/or propionate, with the largest differentiation being the depletion of Faecalibacterium in the lower gastrointestinal tract of CD patients. Notably, PPI users exhibited an enrichment of Faecalibacterium in the lower gastrointestinal tract. The severity of gastrointestinal symptoms, as well as the symptom response to the SNC, were significantly associated with MAM composition in the gastrointestinal tract. The absolute and relative composition of the MAM is variable across different segments of the gastrointestinal tract. These quantitative changes indicates that MAM can be targeted in specific segments of the GI tract to improve patient outcomes.

Comparative analysis of international and Malaysia approaches to the treatment of patients with chronic gastritis from the point of view of evidence-based medicine

Background: Chronic gastritis, often resulting from *Helicobacter pylori* infection, is a widespread gastrointestinal disorder. The condition requires evidence-based treatment approaches to ensure effective management and improved patient outcomes. This study conducts a comparative analysis of the treatment approaches for chronic gastritis in Malaysia and internationally, focusing on adherence to evidence-based medicine (EBM) practices. Understanding the similarities and differences in these approaches is critical for enhancing Malaysia's healthcare strategies. Methods and Materials: The study employed a systematic review of relevant literature sourced from global medical databases, including PubMed, Embase, and Cochrane Library. The review focused on therapeutic options, diagnostic standards, and evidence-based protocols for managing chronic gastritis, with emphasis on both international and Malaysian healthcare systems. Studies included in the review primarily focused on adult patients diagnosed with chronic gastritis and treated using evidence-based methodologies. Results: The analysis revealed significant parallels in the treatment protocols between Malaysia and international guidelines, particularly in the use of proton pump inhibitors (PPIs) and antibiotic regimens for *H. pylori* eradication. However, differences emerged in the implementation of advanced diagnostic tools, accessibility of healthcare services, and the influence of local antibiotic resistance patterns. While Malaysia follows global best practices, rural-urban healthcare disparities impact the consistency of treatment delivery and patient outcomes. Conclusion: Both international and Malaysian approaches to chronic gastritis prioritize evidence-based medicine. The findings suggest that Malaysia effectively adapts international guidelines to its local healthcare context, though improvements are needed in addressing healthcare accessibility and antibiotic resistance. Enhanced implementation of EBM practices, particularly in rural areas, and personalization of treatment based on resistance patterns, could further optimize patient outcomes in Malaysia.

Prophylactic Proton Pump Inhibitors in Upper Gastrointestinal Bleeding: Impact and Underprescription in a French Multicentric Cohort.

Appropriate prescription of Proton pump inhibitors (PPIs) remains an important concern amid the rising overuse. A gap exists in the literature regarding the benefit of PPI prophylaxis and the consequences of underprescription in patients at risk for upper gastrointestinal bleeding (UGIB). This study aims to describe the characteristics of hemorrhage in relation to PPI use in patients experiencing UGIB, with a focus on high-risk individuals requiring gastroprotection. Data from a French multicentric cohort of patients experiencing UGIB were analyzed. Patients using PPI were compared to those without PPI considering bleeding etiologies and outcomes of peptic ulcer disease (PUD)-related hemorrhage. The rate of PPI use and its effect on bleeding characteristics in high-risk populations, defined based on international guidelines, were also assessed. Among 2497 included patients, 31.1% were on PPI at bleeding onset. PPI users exhibited a significantly lower rate of PUD-related bleeding in comparison with those without PPI (24.7 vs 40.8%, respectively, p < 0.0001). Similar difference was observed in high-risk populations, of whom, only 40.3% had gastroprotection with PPI before bleeding onset. PPI prophylaxis, however, did not influence the severity of bleeding in the general study population or in high-risk groups. Multivariate analysis identified age, comorbidities, and having more than two anti-thrombotic agents as predictors of severe bleeding. PPI users appear to have a lower rate of bleeding ulcers compared to non-users. However, underprescription in high-risk groups raises the need for standardized care to ensure appropriate PPI use.

Investigation into transport behavior of platinum‐Nafion interface with functionalized graphene oxide

AbstractIn the catalytic layer of proton exchange membrane fuel cells, water molecules in ionomers tend to be accumulated at the ionomer/Pt interface, preventing oxygen from reaching the Pt surface to participate in chemical reactions. It is necessary to take measures to improve the water molecules distribution and proton transport performance in the ionomer on the Pt surface. In this work, the effect of “acid–base pair” functionalized graphene oxide (AB‐GO) as the additive on the distribution of water molecules and transport property in the ionomer is evaluated. The results demonstrate that with the addition of AB‐GO, the distribution uniformity of water molecules and hydronium ions in the ionomer on the Pt surface is improved. The connectivity of water cluster is also increased. When the doping ratio of BAF‐GO and TF‐GO is 1:3, the connectivity coefficient of water cluster is about 1.37 times that of Nafion ionomer without the doping.

Knowledge and Attitudes Regarding the Inappropriate Use of Proton Pump Inhibitors Among Students of Umm Al-Qura University in Saudi Arabia: A Cross-Sectional Study

Knowledge and Attitudes Regarding the Inappropriate Use of Proton Pump Inhibitors Among Students of Umm Al-Qura University in Saudi Arabia: A Cross-Sectional Study

Editorial Comment on “Association Between Proton Pump Inhibitor Use and Overactive Bladder Risk in Adults: A Cross-sectional Study”

Editorial Comment on “Association Between Proton Pump Inhibitor Use and Overactive Bladder Risk in Adults: A Cross-sectional Study”

Long-Time Scale Simulations Reveal Key Dynamics That Drive the Onset of the N State in the Proteorhodopsin Photocycle.

Proteorhodopsin (PR) is a microbial proton pump that plays a significant role in phototrophy of bacteria in marine environments. Fundamental understanding of the structure-function relationship that drives proton pumping in PR has largely been elusive due to a lack of high-resolution structures of the photointermediates in the PR photocycle. Extending upon previous work, we used long-time scale molecular dynamics (MD) simulations to characterize the M state of the blue variant of PR, which represents the first proton transfer that takes place in the photocycle. Several notable structural changes occur in the M state that are hallmarks of subsequent steps in the PR photocycle, indicating that although this protein is often compared to the canonical microbial rhodopsins, such as bacteriorhodopsin, PR possesses characteristics that make it distinct among the rapidly increasing and widely variable catalog of microbial rhodopsins.

New connections of medication use and polypharmacy with the gut microbiota composition and functional potential in a large population

Medication can affect the gut microbiota composition and function. The aim of this study was to investigate connections between use of common non-antibiotic medicines and the gut microbiota composition and function in a large Swedish cohort (N = 2223). Use of 67 medications and polypharmacy (≥ 5 medications), based on self-reported and prescription registry data, were associated with the relative abundance of 881 gut metagenomic species (> 5% prevalence) and 103 gut metabolic modules (GMMs). Altogether, 97 associations of 26 medications with 40 species and of four medications with five GMMs were observed (false discovery rate < 5%). Several earlier findings were replicated like the positive associations of proton pump inhibitors (PPIs) with numerous oral species, and those of metformin with Escherichia species and with lactate consumption I and arginine degradation II. Several new associations were observed between, among others, use of antidepressants, beta-blockers, nonsteroidal anti-inflammatory drugs and calcium channel blockers, and specific species. Polypharmacy was positively associated with Enterococcus faecalis, Bacteroides uniformis, Rothia mucilaginosa, Escherichia coli and Limosilactobacillus vaginalis, and with 13 GMMs. We confirmed several previous findings and identified numerous new associations between use of medications/polypharmacy and the gut microbiota composition and functional potential. Further studies are needed to confirm the new findings.

Design of a phase 3, randomized, double-blind, placebo-controlled, 48-week study to evaluate the efficacy and safety of cendakimab in adult and adolescent patients with eosinophilic esophagitis

BackgroundEosinophilic esophagitis (EoE) is a chronic, immune-mediated inflammatory condition that interferes with normal food ingestion, negatively impacting quality of life (QoL). Treatment options include proton pump inhibitors, corticosteroids, biologics, or dietary elimination; however, ∼1/3 of patients remain insufficiently controlled. The pathogenesis of EoE involves interleukin-13 (IL-13); therefore, targeted IL-13 inhibition may be beneficial. In a phase 2 study, cendakimab, a recombinant, humanized anti–IL-13 monoclonal antibody, significantly reduced mean esophageal eosinophil counts and improved other inflammatory parameters in patients with EoE. These findings prompted further investigation of the efficacy and safety of cendakimab in adults and adolescents with EoE in a phase 3 registrational study (NCT04753697), the design of which is presented here. MethodsThis multicenter, multinational, randomized, double-blind, placebo-controlled, 48-week, treat-through study plans to enroll 399 adults and adolescents. Randomized patients (1:1:1) will receive subcutaneous administration of 1) cendakimab 360 mg once weekly (QW) for 48 weeks, 2) cendakimab 360 mg QW for 24 weeks followed by cendakimab 360 mg every other week (with matching placebo on alternative weeks to maintain the blind) for 24 weeks, or 3) placebo QW for 48 weeks. Co-primary endpoints are mean change from baseline in dysphagia days and proportion of patients with eosinophil histologic response, defined as peak esophageal eosinophil count ≤6 per high-power field, at 24 weeks. Secondary and exploratory endpoints will address endoscopic and histologic features, QoL, safety, and pharmacokinetic assessments. ConclusionThis phase 3 pivotal study will determine whether cendakimab provides an effective, safe, targeted treatment for patients with EoE.

Awareness, knowledge, and behaviour of Jordanian public regarding misuse and overuse of proton pump inhibitors

Awareness, knowledge, and behaviour of Jordanian public regarding misuse and overuse of proton pump inhibitors

Assessment of proton pump inhibitors utilization in intensivecare units patients of a tertiary care hospital in the United ArabEmirates

Assessment of proton pump inhibitors utilization in intensivecare units patients of a tertiary care hospital in the United ArabEmirates

Salivary microbiota composition before and after use of proton pump inhibitors in patients with laryngopharyngeal reflux: a self-control study

BackgroundIssues associated with proton pump inhibitor (PPI) usage have been documented. PPIs affect the gastrointestinal microbiome, as well as the saliva microbiota of healthy individuals. However, the alterations in the saliva microbiota of laryngopharyngeal reflux (LPR) patients remain unclear. This study aims to examine the composition of saliva microbiota in LPR patients before and after PPI usage through a self-controlled study.MethodsThirty-two adult LPR patients participated in the study. Saliva samples were collected before and after an 8-week regimen of twice-daily administration of 20-mg esomeprazole. The impact of PPI administration on bacterial communities was assessed using 16 S rRNA gene sequencing. The functional and metabolic changes in saliva microbial communities after PPI usage were analyzed using PICRUSt2 based on our 16 S rRNA gene sequencing results.ResultsThe alpha diversity within the salivary microbiota, as measured by the PD-whole-tree index, exhibited a significant difference between samples collected before and after PPI application (P = 0.038). Additionally, PCoA analysis of unweighted UniFrac distances (beta diversity) revealed distinct separation of saliva sample microbiota structures before and after PPI application in LPR patients, with statistical significance (Adonis test, R2 = 0.063, P< 0.010). Taxon-based analysis indicated that PPI administration increased the abundance of Epsilonproteobacteria, Campylobacterales, Campylobacteraceae, Campylobacter, and Campylobacter_gracilis, while reducing the abundance of Lactobacillaceae and Lactobacillus in salivary samples ( P< 0.050). Using LEfSe to compare bacterial abundances, Bacillaceae and Anoxybacillus were found to be enriched before PPI usage in LPR patients. Furthermore, the proportion of genes responsible for indole alkaloid biosynthesis in the salivary microbiota of LPR patients significantly increased after PPI therapy (P< 0.050).ConclusionsThese findings indicate that PPIs induce alterations in the salivary microbiota of LPR patients.Chinese clinical trial registryNo. ChiCTR2300067507. Registered on January 10,2023 retrospectively.Level of evidence4.

Deprescribing of proton pump inhibitors in older patients: A cost-effectiveness analysis.

Over-prescribing of proton-pump inhibitors (PPIs) is widely observed in older patients. Clinical findings have showed that deprescribing service significantly decreased inappropriate PPIs utilization. We aimed to examine the cost-effectiveness of PPI deprescribing service from the perspective of Hong Kong public healthcare provider. A decision-analytic model was constructed to examine the clinical and economic outcomes of PPI deprescribing service (deprescribing group) and usual care (UC group) in a hypothetical cohort of older PPI-users aged ≥65 years in the ambulatory care setting. The model inputs were retrieved from literature and public data. The model time-frame was one-year. Base-case analysis and sensitivity analysis were performed. Primary model outcomes were direct medical cost and quality-adjusted life-years (QALYs) loss. In base-case analysis, the deprescribing service (versus UC) reduced total direct medical cost by USD235 and saved 0.0249 QALY per PPI user evaluated. The base-case results were robust to variation of all model inputs in one-way sensitivity analysis. In probabilistic sensitivity analysis, the deprescribing group was accepted as cost-effective (versus the UC group) in 100% of the 10,000 Monte Carlo simulations. In conclusion, the PPI deprescribing service saved QALYs and reduced total direct medical cost in older PPIs users, and showed a high probability to be accepted as the cost-effective option from the perspective of public healthcare provider in Hong Kong.

Proton Pump Inhibitors and Oral-Gut Microbiota: From Mechanism to Clinical Significance.

Proton pump inhibitors (PPIs) are some of the most commonly prescribed drugs worldwide, but there are increasing concerns about digestive complications linked to PPIs. Next-generation sequencing studies have suggested that PPIs can significantly affect the composition of the gut microbiota, which in turn may substantially contribute to the development of these complications. Recently, emerging evidence has suggested that the translocation of oral microbes into the gut may be the primary mechanism underlying the alterations in the gut microbiota induced by PPIs in the presence of gastric acid suppression and impaired oral-gut barrier function. Moreover, the significance of oral-gut microbial translocation in health and disease conditions has gained increasing recognition. Consequently, it is imperative to enhance our understanding of the functions of the oral-gut microbiota axis in digestive disorders associated with PPI therapies. This review aims to summarize current research findings and further elucidate the contribution of the oral-gut microbiota to the pathogenesis of PPI-related digestive diseases. We aim to provide a theoretical foundation for future therapeutic and preventive strategies targeting PPI-related digestive complications through modulation of the oral-gut microbiota.

A Molten Alkali Approach to Tailor Hydroxyl Groups of Hexaazatrinaphthalene Toward High-Capacity and Low-Potential Anode of Aqueous Proton Batteries.

Hexaazatrinaphthalene (HATN) has attracted a lot of attention in aqueous proton batteries (APBs). However, its redox potential as an anode is insufficiently negative. The introduction of electron-donating substituent groups, such as hydroxyl groups, is considered as a good approach to reduce the redox potential of HATN. Nevertheless, manufacturing hydroxyl-substituted HATN (HATN-OH) requires either expensive precursors or multi-step process, limiting their research. Herein, a straightforward strategy is proposed to synthesize HATN-OH based on the nucleophilic substitution reaction of halogenated HATN in a molten alkali. The redox potential of 1,2,7,8,13,14-hexahydroxy-5,6,11,12,17,18-hexaazatrinaphthalene (34-HATN-6OH) electrode may be lowered by 0.15V in comparison to HATN, and exhibits a high specific capacity, low redox potential, remarkable rate capability, and outstanding long-term cycling performance. The electrochemical redox kinetics is significantly enhanced owing to the formation of rapid proton transport channels created by intermolecular hydrogen bond network. The assembled MnO2||34-HATN-6OH full battery delivers a high discharge voltage (1.16V) and cycling stability (74% capacity retention after 5000 cycles). This study provides a general cost-effective molten alkali approach for the synthesis of hydroxyl-substituted conjugated small molecules from their halogenated counterparts and further enriches the regulation means of electro-chemical performances of organic electrodes for enabling high-capacity and high-voltage APBs.

7686 A Case Of A 66-Year-Old Male With Systemic Macrocytosis Complicated By Osteoporosis

Abstract Disclosure: J.M. Gri: None. M. Hillhouse: None. P. madhavan: None. Background: Osteoporosis in men is underestimated and warrants investigation for secondary causes of osteoporosis. Systemic mastocytosis is a rare secondary cause of osteoporosis. Clinical Case: This is a 66-year-old male with a past medical history of severe persistent asthma, eczema, hypertension, GERD with esophagitis, basal cell carcinoma, and systemic mastocytosis (diagnosed in 2010). Family history was significant for lung cancer in both of his parents. Patient was first noted to have hyperpigmented skin lesions on his legs, trunk and upper extremities in the early 1990s. The spots were biopsied and he was diagnosed with urticaria pigmentosa in 1998. Due to persistent symptoms of facial flushing and soft stool, he was referred to Hematology and was started on antihistamines. He later underwent a bone marrow biopsy in 2010 which showed multifocal mast cell aggregates but normal trilineage hematopoiesis. He endorsed back pain shortly after his diagnosis and a DXA scan was completed. The DXA scan showed osteopenia of the spine T score of -1.8, BMD 0.999 mg/mm3 and normal bone density in bilateral hips. He had no history of fractures. He was started on alendronate and remained on the medication from 2012 to 2015. It was stopped due to intolerable symptoms of acid reflux and he required proton pump inhibitors. DXA scan in 2017 showed normal bone density of the hips and osteopenia of the lumbar spine (T score -1.2). DXA scan in 2022 showed a decrease in spine BMD by 6% (T score -1.8) from 2017 to 2022 but unchanged from 2010. Hip bone mineral density was normal but decreased by 10% since 2010 and by 6% since 2017. Labs obtained in May 2022 showed normal serum electrophoresis, normal urine calcium and creatinine ratio, calcium and vitamin D level and urine NTX of 41 nM BCE/mM (21-83) and bone specific alkaline phosphatase level of 31.5 U/L (15-41.3). After discussion with the patient, conservative management with calcium, vitamin D and exercise has been implemented along with close follow up. Should the patient’s bone turnover markers increase or fracture risk increase, additional antiresorptive therapy will be initiated. Conclusion: This case study highlights the importance of screening for osteoporosis in patients with systemic macrocytosis. As this patient was diagnosed with osteopenia at age 53, this case also emphasizes the importance of early screening in both women and men with this rare condition. Presentation: 6/3/2024

8079 PPI Breaks a Leg! An Unusual Case of Atypical Femur Fracture

Abstract Disclosure: M. Sedghian: None. M. Flanagan: None. D. Pinkhasova: None. K. Selk: None. G. Moloney: None. Background: Atypical femur fractures (AFF) occur along the shaft of the femur extending from the subtrochanteric region proximally to the distal femoral metaphysis. These fractures have an increased incidence in patients taking bisphosphonates and denosumab for osteoporosis and develop as stress reactions in the lateral cortex of the femoral shaft (beaking). However, few cases that meet the characteristics of these fractures have occurred in patients who have never used antiresorptive drugs. We present a case with a history of long-term proton pump inhibitor (PPI) use and possible association with AFF. Clinical Case: The patient is a 68-year-old female with a past medical history of hypothyroidism who presented to the emergency department (ED) after an atraumatic femur fracture and consequently ground level fall. The patient reported experiencing a distinctive cracking sound in her femur while leaning over to wash her feet, resulting in a fall that prompted her to seek immediate care in the ED. Upon initial evaluation, radiographic imaging was significant for displaced left mid-femoral diaphyseal fracture and right femur lateral cortex thickening consistent with AFF. Labs were consistent with elevated PTH to 100.7 [18.4-80.1], Vit D2 1,25 (OH)2 &amp;lt;8 pg/mL, Vit D 25OH 34 ng/ml [30-100], and Calcium level of 9.5. Upon further history taking, the patient stated that she has been taking PPIs intermittently for more than 10 years. She denied a history of bisphosphonate and denosumab exposure, non-Hodgkin's lymphoma, rheumatoid arthritis, and COL1A2 variant mutations as main predisposing factors for atypical femur fractures. She had potential steroid exposure for less than a year before hospitalization as she was on "adrenal complex" from her functional medicine provider. The patient underwent open reduction and internal fixation of the left femur with placement of intramedullary nail and prophylactic fixation with placement of intramedullary nail of the right femur as there was radiographic evidence of beaking. Discussion/Conclusion: Several studies suggested a possible association between PPIs and fracture risk, especially hip fractures, but the relationship remains contentious. Overall, PPIs are positively associated with elevated fracture risk in multiple studies. Increased gastrin production and hypochlorhydria are the two main mechanisms that affect bone remodeling, decreasing bone turnover, impairing calcium absorption, and altering homocysteine levels through impairment of folate and vitamin B12 absorption.This case supports a potential association between long-term PPI use and atypical femur fractures. There have been other case reports that also highlight this potential risk of PPI use. This shows the importance of more comprehensive research on this topic as the number of patients on long-term PPIs is growing in outpatient settings. Presentation: 6/2/2024

Global Transcriptomic Analysis of Topical Sodium Alginate Protection against Peptic Damage in an In Vitro Model of Treatment-Resistant Gastroesophageal Reflux Disease.

Breakthrough symptoms are thought to occur in roughly half of all gastroesophageal reflux disease (GERD) patients despite maximal acid suppression (proton pump inhibitor, PPI) therapy. Topical alginates have recently been shown to enhance mucosal defense against acid-pepsin insult during GERD. We aimed to examine potential alginate protection of transcriptomic changes in a cell culture model of PPI-recalcitrant GERD. Immortalized normal-derived human esophageal epithelial cells underwent pretreatment with commercial alginate-based anti-reflux medications (Gaviscon Advance or Gaviscon Double Action), a matched-viscosity placebo control, or pH 7.4 buffer (sham) alone for 1 min, followed by exposure to pH 6.0 + pepsin or buffer alone for 3 min. RNA sequencing was conducted, and Ingenuity Pathway Analysis was performed with a false discovery rate of ≤0.01 and absolute fold-change of ≥1.3. Pepsin-acid exposure disrupted gene expressions associated with epithelial barrier function, chromatin structure, carcinogenesis, and inflammation. Alginate formulations demonstrated protection by mitigating these changes and promoting extracellular matrix repair, downregulating proto-oncogenes, and enhancing tumor suppressor expression. These data suggest molecular mechanisms by which alginates provide topical protection against injury during weakly acidic reflux and support a potential role for alginates in the prevention of GERD-related carcinogenesis.

Enhanced proton transfer in proton exchange membrane fuel cells via novel nanocomposite membrane incorporating (3-Mercaptopropyl)trimethoxysilane-graphene oxide and basic amino ligands: A synergistic acid-base approach

A nanocomposite polymer electrolyte membrane (MGC) was synthesized by blending MPTS (HS(CH2)3Si(OCH3)3) and graphene oxide (GO) nanosheets at varying weight ratios (91.5 to 9.5, respectively) for proton exchange membrane fuel cell (PEMFC) applications. By covalently modifying the GO support with MPTS through a silane modification process, the acidic MGC matrix is formed. The blending process, with ultrasonication and vigorous stirring, initiates two significant reactions in reactive MPTS: first, the conversion of methoxy groups (Si–OCH3) to silanols (Si-OH); second, the potential condensation of silanol groups to form siloxane bonds (Si–O–Si), followed by oxidation of sulfhydryl groups to sulfonic acid (-SO3H) groups by hydrogen peroxide. The resulting -SO3H groups connected to the siloxane network (Si-O-Si) adjacent to the GO. Two basic amino ligands – dopamine, and aminopropyl trimethoxysilane (APTES) were incorporated into the MGC matrix to establish acid-base pairs, promoting swift proton transport. These additions, at weight ratios of (0.5, 1, 2, and 7) wt%, synergistically contributed to the MGC matrix, forming effective proton channels. Various analytical techniques, including field emission-scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), Raman spectroscopy, X-ray diffraction (XRD), and electrochemical impedance spectroscopy (EIS), were employed to assess the impact of functionalized basic amino groups on the MGC matrix. Notably, the MGC membrane containing 2 wt% of PDA as basic amino ligands exhibited optimal performance, showcasing an in-plane proton conductivity of 115.10 mS cm-1 under fully hydrated conditions at 90 °C, and the maximum power density (MPD) of 170.74 mW cm-2 with a current density of 1051.46 mA cm-2 at 60 °C and 100 % relative humidity (RH). In contrast, the MGC membrane, devoid of amino ligands, exhibited a comparatively low in-plane conductivity of 44.32 mS cm⁻¹ under identical conditions at 90 °C. Additionally, it recorded the MPD of 48.5 mW cm⁻², corresponding to a current density of 313.25 mA cm⁻² at 60 °C and 100 % RH. This study introduces an innovative approach for developing high-performance nanocomposite membranes for PEMs and related applications.