Langmuir最新文献

{"title":"Coalescence Mechanism Induced by Different Wetting States of Ti and Al Droplets on Rough Surfaces","authors":"Zhichao Li, Ruopu Zhao, Tao Li, Wenlong Liu, Qingshui Liu, Mengshuang Fu, Jifeng Tang, Weikang Wu, Hui Li","doi":"10.1021/acs.langmuir.4c02841","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c02841","url":null,"abstract":"There is currently increasing interest in droplet transportation and coalescence on rough surfaces. However, the relationship among wettability, coalescence mode, and substrate characteristics (roughness and nanopillar height) remains unclear. In this work, two coalescence modes, climbing coalescence and contacting coalescence, are first observed in the dynamic behaviors of Ti and Al droplets on rough substrates. Due to the nonsynchronized wetting state transition of the droplets, the coalescence mode with increasing substrate characteristics differs, transitioning from contacting coalescence to climbing coalescence and then returning to the contacting mode. In general, the mode of coalescence correlates closely with the respective wetting states. Typically, Ti and Al droplets coalesce in the contacting mode when they have the same wetting state, but if they have different wetting states, they coalesce in the climbing mode. Our results emphasize the complicated relationship between the surface structure and the wettability of droplets, which could provide insights into self-assembly, three-dimensional printing, and microfluidic devices.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142452022","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":"Improving the Stability, Water Solubility, and Antioxidant Activity of α-Tocopherol by Encapsulating It into Niosomes Modified with Cationic Carbamate-Containing Surfactants","authors":"Rushana Kushnazarova, Alla Mirgorodskaya, Kseniya Bushmeleva, Alexandra Vyshtakalyuk, Oksana Lenina, Konstantin Petrov, Lucia Zakharova","doi":"10.1021/acs.langmuir.4c02507","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c02507","url":null,"abstract":"The low solubility of α-tocopherol in water and its susceptibility to photodegradation make it difficult for biological systems to absorb this natural antioxidant. To overcome these limitations, α-tocopherol was encapsulated in low-toxicity nanocontainers, namely, niosomes based on Tween 80 and cholesterol. The niosomes were modified with cationic surfactants containing a carbamate fragment. The size and charge of the particles were determined and their stability was assessed using dynamic and electrophoretic light scattering methods. It was found that the introduction of cationic surfactants to niosome formulations significantly improved their physicochemical properties and increased stability due to a positive charge of up to +40 mV being generated. Modified niosomes loaded with α-tocopherol were characterized by a hydrodynamic diameter of 100–120 nm, a narrow particle size distribution, and a high encapsulation efficiency of more than 90%. Testing the photochemical stability of α-tocopherol using a spectrophotometric method demonstrated that niosomes were able to protect this substance from UV irradiation. Luminescence analysis showed that the inclusion of α-tocopherol in niosomes increased their antioxidant activity by 30%. An acute toxicity study has demonstrated the safety of the systems. The LD₅₀ value for niosomes modified with carbamate-containing surfactants and loaded with α-tocopherol exceeded 10,000 mg·kg^–1 (mice, intraperitoneal and oral administration).","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142451671","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":"Biosensing of Bacterial Secretions via Topological Defects at Smectic Interfaces","authors":"Vajra S. Badha, Tagbo H. R. Niepa, Mohamed Amine Gharbi","doi":"10.1021/acs.langmuir.4c02698","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c02698","url":null,"abstract":"Characterizing the anchoring properties of smectic liquid crystals (LCs) in contact with bacterial solutions is crucial for developing biosensing platforms. In this study, we investigate the anchoring properties of a smectic LC when exposed to <i>Bacillus subtilis</i> and <i>Escherichia coli</i> bacterial suspensions using interfaces with known anchoring properties. By monitoring the optical response of the smectic film, we successfully distinguish different types of bacteria, leveraging the distinct changes in the LC’s response. Through a comprehensive analysis of the interactions between bacterial proteins and the smectic interface, we elucidate the potential underlying mechanisms responsible for these optical changes. Additionally, we introduce the utilization of topological defects, the focal conic domains (FCDs), at the smectic interface as an indicative measure of the bacterial concentration. Our findings contribute to the understanding of bacteria–LC interactions and demonstrate the significant potential of smectic LCs and their defects for biosensing applications, paving the way for advancements in pathogen detection and protein-based sensing.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142452117","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":"Development and Application of an Advanced Percolation Model for Pore Network Characterization by Physical Adsorption","authors":"Jakob Söllner, Alexander V. Neimark, Matthias Thommes","doi":"10.1021/acs.langmuir.4c01042","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c01042","url":null,"abstract":"Physical adsorption is one of the most widely used techniques to characterize porous materials because it is reliable and able to assess micro- and mesopores within one approach. Challenges and open questions persist in characterizing disordered and hierarchically structured porous materials. This study introduces a pore network model aimed at enhancing the textural characterization of nanoporous materials. The model, based on percolation theory on a finite-sized Bethe lattice, includes all mechanisms known to contribute to adsorption hysteresis in mesoporous pore networks. The model accounts for delayed and initiated condensation during adsorption as well as equilibrium evaporation, pore blocking, and cavitation during desorption. Coupled with dedicated nonlocal-density functional theory kernels, the proposed method provides a unified framework for modeling the entire experimental adsorption–desorption isotherm, including desorption hysteresis scans. The applicability of the method is demonstrated on a selected set of nanoporous silica materials exhibiting distinct types of hysteresis loops (types H1, H2a, H1/H2a, and H5), including ordered mesoporous silica networks (KIT-6 and SBA-15/MCM-41 hybrid silica with plugged pores) and disordered mesoporous silica networks (hierarchical meso-macroporous monolith and porous Vycor glass). For all materials, a good correlation is found between calculated and experimental primary isotherms as well as desorption scans. The model allows us to determine key pore network characteristics such as pore connectivity and pore size distributions as well as a parameter correlated with the impact of pore network disorder on the adsorption behavior. The versatility and enriched textural insights provided by the proposed novel network model allow for a comprehensive characterization previously inaccessible and hence will contribute to further advancement in the textural characterization of novel nanoporous materials. It has the potential to provide important guidance for the design and selection of porous materials for optimizing various applications, including separation processes such as chromatography, heterogeneous catalysis and gas and energy storage.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142452094","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":"Equilibrium States of a Liquid Bridge between Flexible Sheets","authors":"Mouad Boudina, Gwynn J. Elfring","doi":"10.1021/acs.langmuir.4c02489","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c02489","url":null,"abstract":"We study the equilibrium states of a drop between flexible sheets clamped on both ends. Revisiting first the case of parallel sheets, we find multiple equilibria, which we classify in a parameter space. In solution branching diagrams, we identify hysteresis cycles and folds indicating abrupt transitions, yet not necessarily leading to channel collapse. Between nonparallel sheets, a drop can stay in equilibrium away from the ends even when the liquid is not totally wetting, which is impossible between nonparallel rigid plates. We also show that nonparallel sheets can delay or prevent collapse in comparison to straight channels, suggesting thus a mechanism that protects slender structures inside microdevices from damage by surface tension.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142452097","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":"Micelle-Assisted C(sp2)–H Functionalization for C–Se and C–X Bond Formation in the Aqueous Medium","authors":"Abhinay S. Chillal, Chandani Maurya, Umesh A. Kshirsagar","doi":"10.1021/acs.langmuir.4c03052","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c03052","url":null,"abstract":"An environmentally sustainable, versatile, and cost-effective approach for C–Se and C–X (X = I, Br, and Cl) bond formation through C–H functionalization assisted by micellar catalysis in water is developed. The reaction utilizes a minimum amount of diorganyl diselenides and potassium halides for the respective functionalizations. The present protocol was suitable for scale-up synthesis, which directly provided the desired selenylated products without the need for chromatographic purification, in sufficient purity. The aqueous micellar catalysis system was reusable for up to 5 reaction cycles without compromising the reaction yield.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142452020","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":"Enhancing mRNA Interactions by Engineering the Arc Protein with Nucleocapsid Domain","authors":"Vaibhav Upadhayay, Wenchao Gu, Qiuming Yu","doi":"10.1021/acs.langmuir.4c03151","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c03151","url":null,"abstract":"Activity-regulated cytoskeleton-associated protein (Arc) forms virus-like capsids for mRNA transport between neurons. Unlike HIV-1 Group-specific Antigen (Gag), which uses its Nucleocapsid (NC) domain to bind HIV-1 genomic mRNA, mammalian Arc lacks the NC domain, and their direct mRNA binding interactions remain underexplored. This study examined rat Arc’s binding to rat Arc 5′ UTR (A5U), HIV-1 5′ UTR (H5U), and GFP mRNAs, revealing weak binding with no significant preference. Adding the HIV-1 NC domain to rArc’s C-terminus significantly improved binding to H5U, while also showing substantial binding to A5U at about 60% of its H5U level and exhibiting twice the affinity for A5U over GFP mRNA. Importantly, rArc-NC binds 3.4 times more A5U and H5U than GST-NC, indicating that rArc NTD-CA aids mRNA binding by HIV-1 NC. These findings suggest a conserved Gag protein–mRNA interaction mechanism, highlighting the potential for developing mRNA delivery systems that combine endogenous Gag NTD-CA with retroviral NC and UTRs.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142452021","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":"Surface Epitaxial Growth of 2D/2D Bi2O2S/CdS Heterojunction Photoanodes and Their Photoelectrochemical Properties","authors":"Xueling Wei, Zhen Ma, Yuanhao Yang, Qiujie Li, Qian Sun, Dekai Zhang, Enzhou Liu, Hui Miao","doi":"10.1021/acs.langmuir.4c03156","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c03156","url":null,"abstract":"Constructing high catalytic activity heterojunctions to compensate for the shortcomings of single catalysts has promoted the development of semiconductor catalysts in photoelectrochemical (PEC) water splitting. In this case, the 2D/2D Bi₂O₂S/CdS composite was successfully constructed by an in situ surface epitaxial growth method. At 1.23 V vs RHE, the catalytic activity of Bi₂O₂S/CdS with a 2D/2D heterojunction is the highest, and the current density of the Bi₂O₂S/CdS photoanode is 3.46 mA/cm². Compared with the Bi₂O₂S photoanode (0.59 mA/cm²), the performance has been improved by 5.86 times. In electrochemical impedance spectroscopy testing, the arc radius of 2D/2D Bi₂O₂S/CdS is smaller than that of Bi₂O₂S, indicating faster charge-transfer kinetics. The data show that the 2D/2D heterojunction with surface–surface contact successfully enhances the catalytic activity of Bi₂O₂S, greatly elevating the efficiency of charge separation and migration. This study provides a method to enhance the PEC activity in type-I heterojunction photoelectrodes, promoting the application of Bi₂O₂S-based materials in photoelectrochemistry.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142452023","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":"Aspartic Acid Binding on Hydroxyapatite Nanoparticles with Varying Morphologies Investigated by Solid-State NMR Spectroscopy and Molecular Dynamics Simulation","authors":"Yuan Li, Christian D. Lorenz, Gregory P. Holland","doi":"10.1021/acs.langmuir.4c02880","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c02880","url":null,"abstract":"Hydroxyapatite (HAP) exhibits a highly oriented hierarchical structure in biological hard tissues. The formation and selective crystalline orientation of HAP is a process that involves functional biomineralization proteins abundant in acidic residues. To obtain insights into the process of HAP mineralization and acidic residue binding, synthesized HAP with specific lattice planes including (001), (100), and (011) are structurally characterized following the adsorption of aspartic acid (Asp). The adsorption affinity of Asp on HAP surfaces is evaluated quantitatively and demonstrates a high dependency on the HAP morphological form. Among the synthesized HAP nanoparticles (NPs), Asp exhibits the strongest adsorption affinity to short HAP nanorods, which are composed of (100) and (011) lattice planes, followed by nanosheets with a preferential expression of the (001) facet, to which Asp displays a similar but slightly lower binding affinity. HAP nanowires, with the (100) lattice plane preferentially developed, show significantly lower affinity to Asp and evidence of multilayer adsorption compared to the previous two types of HAP NPs. A combination of solid-state NMR (SSNMR) techniques including ¹³C and ¹⁵N CP-MAS, relaxation measurements and ¹³C–³¹P Rotational Echo DOuble Resonance (REDOR) is utilized to characterize the molecular structure and dynamics of Asp-HAP bionano interfaces with ¹³C- and ¹⁵N-enriched Asp. REDOR is used to determine ¹³C–³¹P internuclear distances, providing insight into the Asp binding geometry where stronger ¹³C–³¹P dipolar couplings correlate with binding affinity determined from Langmuir isotherms. The carboxyl sites are identified as the primary binding groups, facilitated by their interaction with surface calcium sites. The Asp chelation conformations revealed by SSNMR are further refined with molecular dynamics (MD) simulation where specific models strongly agree between the SSNMR and MD models for the various surfaces.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142452098","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":"Research on the Mechanism of Femtosecond Laser Ablation Concave-Convex Microstructure Transformation","authors":"Jinkui Cao, Baoji Ma, Liangliang Li, Xiangyu Li, Chaopeng Xu, Xinbo Wang","doi":"10.1021/acs.langmuir.4c02455","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c02455","url":null,"abstract":"The phenomenon of femtosecond laser ablation of convex structures from the bottom to the top is interesting. In this study, AZ31B magnesium alloy was used as the substrate to analyze the impact of the laser pulse energy and scanning speed on the morphology of concave-convex microstructures. Subsequently, a unified two-dimensional numerical model incorporating solid, liquid, and gas phases was established, and combined with experimental data, the mechanism and formation process of concave-convex transformation in magnesium alloy under laser ablation were revealed. The results indicate that the transition from concave to convex structures is significantly influenced by the laser scanning speed, whereas the laser pulse energy primarily affects the shape and size of the convex structures. During the ablation process, molten material is expelled and gradually accumulates on both sides of the ablation groove under the action of the recoil pressure. During cooling, the molten material at both ends of the groove merges to form protrusions under the combined effects of internal negative pressure, gravity, and Marangoni forces. Moreover, this method of femtosecond laser ablation for generating convex structures deviates from the traditional single-texture approach to concave structures, potentially broadening the application of laser composite processing surfaces.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142452096","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}