Langmuir最新文献

Cytoplasmic lipid droplets form from the endoplasmic reticulum (ER). Because the ER membrane can undergo phase separation, the interaction of lipid droplets with phase-separated bilayers is of significant interest. In this study, we used fluorescence microscopy to investigate the incorporation of droplets composed of triolein, trilinolein, trimyristolein, trieicosenoin, and cholesteryl arachidonate in the bilayers of giant unilamellar vesicles (GUVs) consisting of a mixture of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), and cholesterol. After the triacylglycerol droplets were incorporated, the DOPC/DPPC/cholesterol (3:3:2) GUVs, which exhibited liquid-disordered (L_d) and liquid-ordered (L_o) phase separation, retained their phase-separated state. The triacylglycerol droplets were predominantly partitioned in the L_d domains. To elucidate the basis of this preferential partitioning, we investigated the surface pressures of DOPC, DPPC, and cholesterol monolayers containing triolein at the air/water interface using a Langmuir trough. From these measurements, we determined the interfacial tension at the monolayer-covered triolein/water interface. The results showed that DOPC most effectively reduced the interfacial tension. Thus, the droplet sorting into the DOPC-enriched L_d domains likely arose from the difference in the abilities of the two phases to stabilize the droplet interface. In contrast, cholesteryl arachidonate had a profound effect on bilayer phase behavior. Fluorescence images of the DOPC/DPPC/cholesterol (3:3:2) GUVs showed that the domain structures disappeared after droplet incorporation. Additionally, surface pressure measurements of DOPC/DPPC/cholesterol (3:3:2) monolayers containing cholesteryl arachidonate at the air/water interface suggested that cholesteryl arachidonate weakened the lipid-lipid interaction. The results indicate that the cholesteryl arachidonate molecules diffused across the bilayer to hinder the bilayer phase separation.

This study combines molecular simulation and experimental methods to investigate the adsorptive separation performance of two metal-organic frameworks (MOFs), ZIF-67 and MIL-53(Al), for Ar/He mixed gases. Experimental and simulation adsorption isotherm data were obtained at temperatures of 298, 200, and 150 K for both Ar and He single-component adsorbates. The ideal adsorbed solution theory (IAST) and grand canonical Monte Carlo (GCMC) simulations calculated the Ar/He selectivity coefficients at different temperatures. Breakthrough experiments analyzed the separation performance of the MOFs with varying feed ratios of Ar/He at 298, 200, and 150 K. Additionally, molecular simulations assessed the isosteric heat of adsorption, adsorption energy distribution, and binding energy, providing insights into competitive adsorption mechanisms. Results showed that both ZIF-67 and MIL-53(Al) preferentially adsorb Ar, with lower temperatures significantly enhancing the separation performance. This preference is linked to differences in the binding energy between the adsorbent sites and the two gas molecules. Breakthrough tests confirmed that both MOFs are effective for Ar/He separation with lower temperatures or higher He concentrations improving He extraction from the mixture.

The surfaces of underwater ship hulls and aquaculture equipment, such as fish cages, are highly susceptible to damage from fouling organisms. Although traditional marine antifouling coatings exhibit effective antifouling properties, the leaching of antifouling agents into the marine environment can lead to pollution and ecological disruption. In this study, we prepared castor oil polyurethane (CO-PU) by reacting castor oil with isocyanate. We then incorporated self-synthesized acrylamide-based quaternary ammonium salts (QASs), specifically dimethyloctylaminopropyl methacrylamide-ammonium QD-BC and its polymer PQDBCAM, into the CO-PU resin to develop CO-PU marine antifouling coatings. By optimizing the formulation to enhance the cross-linking degree of the coating, we obtained coatings with improved mechanical properties and antifouling performance. The results indicate that, in comparison to the pure CO-PU coating, the hydrophilicity of the coating is enhanced, the flexibility is superior, the pencil hardness increases from 5H to 6H, and the adhesion of the PQDBCAM antifouling coating reaches a maximum of 4.79 MPa. All of the coatings demonstrated effectiveness in inhibiting the growth of Pseudomonas aeruginosa, diatoms, and protein attachment, and the increase of QASs leads to enhanced effects. This suggests that acrylamide QAS marine antifouling coatings have a certain degree of antifouling performance, and polymer-based quaternary ammonium PQDBCAM antifouling coatings show superior efficacy. After the 3.6% PQDBCAM coating was statically placed in diatoms for 7 days, the coverage area of diatoms was merely approximately 22.3% and the protein adsorption amount on the surface of the antifouling coating was 31.72 μg/cm². The coating could maintain its integrity after 3 months and still exhibit excellent antibacterial effects. The antifouling effect was more durable, effectively reducing the maintenance times of ships and the cleaning frequency of aquaculture equipment.

Noncovalent interactions, both between molecules and at the molecule-electrode interfaces, play essential roles in enabling dynamic and reversible molecular behaviors, including self-assembly, recognition, and various functional properties. In macroscopic ensemble systems, these interfacial phenomena often exhibit emergent properties that arise from the synergistic interplay of multiple noncovalent interactions. However, at the single-molecule scale, precisely distinguishing, characterizing, and controlling individual noncovalent interactions remains a significant challenge. Molecular electronics offers a unique platform for constructing and characterizing both intermolecular and molecule-electrode interfaces governed by noncovalent interactions, enabling the isolated study of these fundamental interactions. Furthermore, precise control over these interfaces through noncovalent interactions facilitates the development of enhanced molecular devices. This review examines the characterization of interfacial phenomena arising from noncovalent interactions through single-molecule electrical measurements and explores their applications in molecular devices. We begin by discussing the construction of stable molecular junctions through intermolecular and molecule-electrode interfaces, followed by an analysis of electron tunneling mechanisms mediated by key noncovalent interactions and their modulation methods. We then investigate how noncovalent interactions enhance device sensitivity, stability, and functionality, establishing design principles for next-generation molecular electronics. We have also explored the potential of noncovalent interactions for bottom-up self-assembled molecular devices. The review concludes by addressing the opportunities and challenges in scaling up molecular electronics through noncovalent interactions.