Langmuir最新文献

{"title":"Portable Mini-Electrochemical Cell: Integrating Microsampling and Micro-Electroanalysis for Multipurpose On-Site Nitrite Sensing","authors":"Shohreh Madani, Amir Hatamie","doi":"10.1021/acs.langmuir.4c03398","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c03398","url":null,"abstract":"In modern analytical chemistry, one of the primary goals is to develop miniaturized, easy-to-use sensing tools, particularly those with multitasking capabilities. In this work, we designed a mini-voltammetric cell that integrates a modified Au microelectrode (Au/Au NPs as the working electrode) and an Ag/AgCl reference electrode installed within a micropipette tip. This combined tool not only enables portable and on-site microvolume sampling─requiring only a microvolume (around 20–40 μL) or a single droplet─but also facilitates direct micro-electroanalysis in a short time. To evaluate its capabilities, the mini-voltammetric cell was optimized for trace analysis of nitrite ions and demonstrated linear responses in the ranges of 20–150 and 150–1200 μM, with an acceptable limit of detection (LOD) of 18.40 μM, meeting both WHO and EPA standards for nitrite levels. Furthermore, it exhibited high selectivity, stability (up to 36 continuous measurements with only a 3.24% signal drop), and acceptable repeatability (RSD of 2.98%, <i>n</i> = 15). The analytical performance of this miniaturized tool was further assessed through the sampling and detection of nitrite ions in various real samples with different matrixes: (1) urine samples, for the fast diagnosis of urinary tract infections (UTIs), where nitrite ions are detected as biomarkers of UTIs; (2) river water polluted with agricultural waste, where nitrite ions serve as pollutants from nitrogen fertilizers; and (3) on the hands and in forensic investigations, where nitrite ions are detected as indicators of gunshot residue, crucial in crime scene examinations. All real samples were analyzed using the standard addition method and recovery tests, yielding acceptable results. Additionally, the proposed mini-analytical tool was evaluated for its sustainability and applicability using two recognized metrics: The Green Analytical Procedure Index (GAPI) and the Blue Applicability Grade Index (BAGI). The results confirmed that this method can be classified as both a green analytical method and highly applicable. Finally, the practical results demonstrated that the proposed miniaturized electroanalytical tool exhibits reliable performance, high sensitivity and selectivity, and fast response in the on-site microanalysis of nitrite, without the need for any reagents or complex sampling steps, across different real samples (such as clinical, forensic, and environmental samples). We believe the proposed mini-voltammetric cell could be used as an alternative to current detection methods, and with suitable modifications, it could be adapted for the microanalysis of other applications and (bio)targets with small volumes in the near future.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"251 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673628","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interplay between Antimicrobial Peptides and Amyloid Proteins in Host Defense and Disease Modulation","authors":"Naiem Ahmad Wani, Ehud Gazit, Ayyalusamy Ramamoorthy","doi":"10.1021/acs.langmuir.4c03123","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c03123","url":null,"abstract":"The biological properties of antimicrobial peptides (AMPs) and amyloid proteins and their cross-talks have gained increasing attention due to their potential implications in both host defense mechanisms and amyloid-related diseases. However, complex interactions, molecular mechanisms, and physiological applications are not fully understood. The interplay between antimicrobial peptides and amyloid proteins is crucial for uncovering new insights into immune defense and disease mechanisms, bridging critical gaps in understanding infectious and neurodegenerative diseases. This review provides an overview of the cross-talk between AMPs and amyloids, highlighting their intricate interplay, mechanisms of action, and potential therapeutic implications. The dual roles of AMPs, which not only serve as key components of the innate immune system, combating microbial infections, but also exhibit modulatory effects on amyloid formation and toxicity, are discussed. The diverse mechanisms employed by AMPs to modulate amyloid aggregation, fibril formation, and toxicity are also discussed. Additionally, we explore emerging evidence suggesting that amyloid proteins may possess antimicrobial properties, adding a new dimension to the intricate relationship between AMPs and amyloids. This review underscores the importance of understanding the cross-talk between AMPs and amyloids to better understand the molecular processes underlying infectious diseases and amyloid-related disorders and to aid in the development of therapeutic avenues to treat them.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"23 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pickering Emulsions Stabilized with Millimeter-Sized Polymer Plates","authors":"Rina Kakiuchi, Yuri Sakurai, Hikaru Manabe, Jun Yamaguchi, Tomoyasu Hirai, Yoshinobu Nakamura, Syuji Fujii","doi":"10.1021/acs.langmuir.4c02843","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c02843","url":null,"abstract":"Hexagonal polymer plates of (sub)millimeter size that were uniform in shape and size were used as a stabilizer for emulsions, and the correlations of plate size, oil polarity, and plate dispersing media before emulsification with the formability, type, and droplet shape of emulsions were studied. The formability of the emulsions was improved by decreasing the plate size. The lower the oil polarity was, the more preferably O/W-type emulsions were formed, and as the oil polarity increased, the formability of W/O-type emulsions increased, whereas too high of an oil polarity resulted in no emulsion formation or macrophase separation of the oil dispersion of the plates and water. Furthermore, when the plate dispersing medium before emulsification was oil, the plates tended to be lipophilic compared with those dispersed in water before emulsification. In addition, we confirmed that there was a correlation between the droplet/stabilizer size ratio and droplet shape: when the droplet/plate size ratios are &gt;2, droplets with near-spherical shapes are formed; when the size ratios are between 1 and 2, droplets with polyhedral shapes (e.g., hexahedral and tetrahedral shapes) are formed; and when the size ratios are &lt;1, sandwich-shaped droplets are formed. Droplets with similar structures tended to form if the droplet/plate size ratios were close, even though the sizes of the plate and droplet were different.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"57 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Portable Microelectrochemical Sensor Based on Potentiostatic Polarization-Treated and Laser-Induced Graphene for the Simultaneous Determination of Ascorbic Acid, Dopamine, and Uric Acid","authors":"Xiaoming Yuan, Xiu-Wen Wu, Shilin Li, Ruwei Liu, Yunhan Ling","doi":"10.1021/acs.langmuir.4c03269","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c03269","url":null,"abstract":"Maintaining normal biomolecular levels in the human body plays a crucial role in controlling various diseases. In this work, we designed a portable microelectrochemical sensor based on laser-induced graphene (LIG) for the simultaneous determination of ascorbic acid (AA), dopamine (DA), and uric acid (UA). A simple electrode surface modification strategy, potentiostatic polarization in an alkali solution, was applied to functionalize the LIG surface with the aim of enhancing the LIG electrocatalytic activity, conductivity, and wettability. After electrochemical pretreatment, the modified electrode displayed significantly enhanced electrocatalytic activity toward AA, DA, and UA, with well-separated characteristic oxidation peaks for each analyte, thus achieving their simultaneous detection without further modification by nanomaterials. Differential pulse voltammetry (DPV) was applied for determining these three analytes. Under optimal conditions, calibration curves were obtained in the ranges 10–5000 μM, 0.1–6000 μM, and 10–8000 nM for AA, DA, and UA, with the detection limits (S/N = 3) of 1.43 μM, 6.83 nM, and 1.07 nM, respectively. The microelectrochemical sensor achieved reliable and satisfactory results in detecting AA, DA, and UA in actual urine samples, demonstrating significant application prospects in human health monitoring and clinical diagnosis.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"4 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142678991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sacrificing Surfactants to Improve Oil Recovery: A Fluid Density Functional Theory Study","authors":"Zheng Xu, Jin Cheng, Yuanlong Hu, Yanghejia Wu, Siyuan Fan, Gaoxin Yu, Yunwen Wang, Cheng Lian, Honglai Liu","doi":"10.1021/acs.langmuir.4c03075","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c03075","url":null,"abstract":"In the chemically enhanced oil recovery (CEOR) processes, heavy components in crude oil, such as asphaltenes, adhere to reservoir rocks, significantly impeding crude oil extraction. Surfactants are frequently utilized to improve oil recovery due to their ability to reduce interfacial tension (IFT) and modify surface wettability. Nevertheless, indiscriminate surfactant usage may result in resource wastage and hinder the attainment of optimal recovery outcomes. Therefore, it is urgent to accurately and efficiently screen out optimal surfactants suitable for different oil fields. This work employs fluid density functional theory (FDFT) to investigate the competitive adsorption mechanism of surfactants and asphaltenes on rock interfaces. We examined the impact of surfactants on asphaltene adsorption and determined the optimal surfactant concentration and chain length for differing reservoir electrical properties and asphaltene compositions. Furthermore, a comprehensive assessment of surfactants was conducted, considering both performance and economic factors. The findings contribute to a deeper comprehension of the displacement effect of surfactants on asphaltenes and offer scientific screening solutions for surfactants in oil recovery processes.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"170 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improved Adsorption of Organic Dyes onto a Polypyrrole/Tannic Acid Nanocomposite","authors":"Nehapadma Mohanty, Sai Sushree Rath, Braja N. Patra","doi":"10.1021/acs.langmuir.4c03158","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c03158","url":null,"abstract":"Methyl orange (MO) and methylene blue (MB) dyes are toxic and carcinogenic; thus, their presence in water bodies has been a major concern. Designing an efficient adsorbent for removal of these dyes is a scientific challenge for researchers. In this work, a polypyrrole–tannic acid nanocomposite was prepared via a chemical oxidation method and used as a novel adsorbent for removing these toxic dyes. The synthesized nanocomposite was characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and Brunauer–Emmett–Teller methods. The effect of different parameters on adsorption such as adsorbent doses, temperature, pH, initial dye concentration, and contact time was studied. The adsorption was in line with pseudo-second-order kinetics and the Langmuir isotherm model. Δ<i>G</i>°, Δ<i>H</i>°, and Δ<i>S</i>° were calculated to ascertain the feasibility of adsorption. The maximum adsorption capacities attained for this adsorbent were found to be 204.08 mg/g toward the MO dye and 217.39 mg/g toward the MB dye.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"251 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Swimming Modes of Bacteria Escaping from a Soft Confined Space","authors":"Yangguang Tian, Xinlei Li, Yaozhen Chen, Xingbin Hu, Yanan Liu, Hao Luo, Guangyin Jing","doi":"10.1021/acs.langmuir.4c03808","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c03808","url":null,"abstract":"Navigating through soft and highly confined environments is crucial for bacteria moving within living organisms’ tissues, yet this topic has been less explored. In our study, we experimentally harnessed the unique biconcave geometry of red blood cells (RBCs) to enable real-time visualization of swimming <i>Escherichia coli</i> interacting with soft RBCs. Our findings show that RBCs adhering to a rigid surface can enclose spaces comparable to the size of bacteria, effectively entrapping them. Remarkably, we found that bacteria can escape from this extremely confined space through three newly defined escape modes: <i>Bundling</i>, <i>Unbundling</i>, and <i>Flipping</i>, each mode relying on the specific states of bacterial flagella. A quantitative analysis uncovers significant differences among these modes in terms of scattering angle, escaping speed, and trapping duration. We used two methods to alter the rigidity and adhesion strength of RBCs, and we studied their effects on the detailed bacterial escape process. Our results contribute to the knowledge of bacterial migration in soft, confined spaces, thereby enhancing our understanding of similar processes in biological tissue environments.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"28 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coarse-Grained Modeling of the Water/Alkane Wetting and Dewetting Processes on Fluorinated Coatings","authors":"Panagiotis C Petris, Georgiy Teverovskiy, Richard Ross, Augustinus J.M Sweere, Jan-Willem Handgraaf","doi":"10.1021/acs.langmuir.4c01560","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c01560","url":null,"abstract":"This work provides a framework to digitally assess any droplet’s static and dynamic contact angles on coatings and polymeric substrates. We are introducing a new dissipative particle dynamics coarse-grained model to attain the spatiotemporal conditions and the coexistence of different phases that such investigation dictates. Two computational techniques are additionally developed; a robust technique to calculate the static contact angle using density profiles and a perturbation method to evaluate dynamic contact angles. A parallel force to the surface force is applied to emulate the receding and advancing dynamics. We have validated our protocols for the static contact angle of water for a series of polymeric surfaces and the dynamic contact angle for three different fluorinated additives. We reproduced the correct hysteresis trends between the droplet content and the surface. The fluorinated nature of the additive’s tails is the driving force of directed self-assembly and, consequently, the repelling nature of the surface. An equally important factor for designating the interaction profile of the surface is the coating’s chemical structure, which is responsible for inhibiting or favoring the aqueous media interaction.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"253 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142678716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring MoS2 Growth: A Comparative Study of Atmospheric and Low-Pressure CVD","authors":"Hemanth Kumar Paidi, Rishitha Mudunuri, Deepu J. Babu","doi":"10.1021/acs.langmuir.4c03567","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c03567","url":null,"abstract":"Transition-metal dichalcogenides (TMDs), in particular MoS₂, have garnered a lot of interest due to their unique properties and potential applications. Chemical vapor deposition (CVD) is generally used to synthesize 2D films of MoS₂. The synthesis of MoS₂ is highly sensitive to growth parameters such as temperature, pressure, flow rate, precursor ratio, etc. Though there are several accounts of MoS₂ synthesis via atmospheric-pressure CVD (APCVD) and low-pressure CVD (LPCVD), there is a lack of a comparative analysis between the two methods, which could potentially offer a better perspective on the growth of MoS₂. This work systematically investigates the growth of MoS₂ under APCVD and LPCVD conditions. The APCVD growth of MoS₂ is found to be diffusion-limited, leading to the characteristic triangular morphology, while the LPCVD growth is reaction-limited. The enhanced mass flux in LPCVD, even at much lower temperatures (Δ<i>T</i> ≥ 200 °C), increases the nucleation density, resulting in a continuous polycrystalline film covering the entire substrate. This comparative study provides a better insight into understanding the crystallization and growth of MoS₂, which can also be extended to other TMDs.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"14 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142679026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An in Silico Investigation into Polyester Adsorption onto Alumina toward an Improved Understanding of Hydrogenolysis Catalysts","authors":"Ziyue Dong, Erin E. Dunphy, Aidan B. Wegner, J. Will Medlin, Michael F. Toney, Kayla G. Sprenger","doi":"10.1021/acs.langmuir.4c03679","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c03679","url":null,"abstract":"Chemical recycling of end-of-life plastic wastes through hydrogenolysis is a promising pathway for achieving a circular plastics economy and reducing overall energy costs. Understanding molecular interactions at the inorganic–organic depolymerization interface is crucial for enhancing catalyst performance and overcoming challenges posed by mixed plastic waste streams. We investigated a fundamental step in the depolymerization process: physisorption of polymers onto the metal oxide support preceding diffusion to and reaction at the catalyst–support junction. Molecular dynamics simulations, augmented with well-tempered metadynamics, were conducted to explore the adsorption of polylactic acid (PLA) and polyethylene terephthalate (PET) oligomers onto a hydroxylated alumina support surface. Our findings revealed multiple layers of highly oriented solvent molecules (1,4-dioxane) above the surface, creating significant barriers to polyester adsorption. Disrupting and displacing these solvent layers led PET oligomers to adsorb closer to and interact stronger with the surface than PLA oligomers, possibly contributing to the higher reaction temperatures needed to achieve full conversion in PET versus PLA hydrogenolysis. We further suggest an experimental approach to validate our results of solvent layering behavior through predictions of X-ray reflectivity that are consistent with our initial experiments. The insights gained in this study can be leveraged to refine our understanding of catalytic mechanisms to predict depolymerization reactivity and selectivity and improve future hydrogenolysis catalyst designs.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"23 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142679027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}