Bilayer Structure Research Articles

A Dual-Recognition Fluorescence Enzyme-Linked Immunosorbent Assay for Specific Detection of Intact Lipid Nanoparticles via a Localized Scaffolding Autocatalytic DNA Circuit Amplifier.

Lipid nanoparticles (LNPs) are emerging as one of the most promising drug delivery systems. The long-circulating effect of intact LNPs (i-LNPs) is the key to efficacy and toxicity in vivo. However, the significant challenge is specific and sensitive detection of i-LNPs. Herein, a dual-recognition fluorescence enzyme-linked immunosorbent assay (DR-FELISA) was developed to directly isolate and detect i-LNPs by combining dual-recognition separation with a one-step signal amplification strategy. The microplates captured and enriched i-LNPs through antibody-antigen reaction. Dual-chol probes were spontaneously introduced into the lipid bilayer of captured i-LNPs, converting the detection of i-LNPs into the detection of double-cholesterol probes. Finally, the end of the dual-chol probes initiated the localized scaffolding autocatalytic DNA circuits (SADC) system for further signal amplification. The SADC system provides a sensitive and efficient amplifier through localized network structures and self-assembled triggers. Simultaneous recognition of i-LNPs surface PEG-lipid and lipid bilayer structures significantly eliminates interference from biological samples. i-LNPs were detected with high selectivity, ranging from 0.2 to 1.25 mg/mL with a limit of detection of 0.1 mg/mL. Moreover, this method allows the isolation and quantitative analysis of different formulations of i-LNPs in serum samples with a satisfactory recovery rate ranging from 94.8 to 116.3%. Thus, the DR-FELISA method provides an advanced platform for the exclusive and sensitive detection of i-LNPs, providing new insights for the study of the quality and intracorporal process of complex formulations.

A Micro Capacitive Humidity Sensor Based on Al-Mo Electrodes and Polyimide Film.

Quickly sensing humidity changes is required in some fields, such as in fuel cell vehicles. The micro humidity sensor used for the relative humidity (RH) measurement with fast response characteristics, and its numerical model and method are rare. This paper firstly presents a numerical model and method for a parallel plate capacitor and a numerical analysis of its dynamic characteristics. The fabrication of this sensor was carried out based on the numerical results, and, the main characteristics of its moisture-sensitive element are shown. This parallel plate capacitor is made using complementary metal-oxide semiconductor (CMOS)-compatible technology, with a P-type monocrystalline silicon wafer used as the substrate, a thin polyimide film (PI) between the upper grid electrode and the lower parallel plate electrode, and electrodes with a molybdenum-aluminum bilayer structure. The shape of the micro sensor is square with 3 mm on the side of the source field. The humidity sensor has a linearity of 0.9965, hysteresis at 7.408% RH, and a sensitivity of 0.4264 pF/%RH. The sensor displays an average adsorption time of 1 s and a minimum adsorption time of 850 ms when the relative humidity increases from 33.2% RH to 75.8% RH. The sensor demonstrates very good stability during a 240 h test in a 25 °C environment. The numerical model and method provided by this study are very useful for predicting the performance of a parallel plate capacitor.

P-117 Extracellular vesicles from fallopian tubal fluid benefit human embryo development in vitro

Abstract Study question Do extracellular vesicles (EVs) from Fallopian tubes benefit human embryo development, and how do they affect preimplantation embryo development? Summary answer The Fallopian tubal EVs can be internalized by human embryos, and they contain miR-21-5p that downregulated P53 in blastocysts. What is known already EVs in the Fallopian tubes are identified as key mediators in embryo-oviduct interactions that contribute to a successful pregnancy in vivo. We previously showed Fallopian tubal EVs can benefit mouse embryo development in vitro. However, if a similar phenomenon can be observed in human embryos and what is the key component in Fallopian tubal EVs remains elusive. Study design, size, duration The EVs were isolated from the luminal fluid of human Fallopian tubes (n = 23). Immature human oocytes were collected and in vitro matured and fertilized, and 2-pronuclei embryos were included in this study and randomly divided (n = 87). We cocultured these zygotes with Fallopian tubal EVs until the blastocyst stage. Further, two-cell mouse embryos were used to explore the expression levels of miRNAs in Fallopian tubal EVs. The effects of miR-21-5p on mouse embryos were analyzed. Participants/materials, setting, methods EVs were isolated using ultracentrifugation. The uptake of labeled EVs by human embryos was analyzed using confocal microscopy. The fragmentation of the day-3 embryos and the blastocyst rate were compared between the control and the EV-treatment group. Then the stage-specific expression of miRNAs was compared in mouse embryos that were either developed in vivo or cultured in vitro. miR-21-5p were supplemented to the culture medium and the p53-related apoptosis in embryos was evaluated. Main results and the role of chance EVs were measured less than 200 nm in diameter with a typical bi-layer membrane structure and expressed protein markers Heat shock protein 70 (HSP70) and CD9. Most of the fluorescence-labeled EVs were attached to the zona pellucida within 2 h of co-culture. However, human embryos internalized EV within 4 h, with fluorescence signals observed in embryonic cells. The fragmentation rate was decreased and the blastocyst rate was increased by EVs. miR-21-5p, which was highly enriched in EVs, was found to be expressed at a significantly lower level in in-vitro-cultured mouse embryos compared to the in-vivo-developed embryos, through the two-cell stage to the eight-cell stage. miR-21-5p agomir supplementation to the culture medium was found to increase the mouse blastocyst formation rate, decrease apoptosis, and downregulate the P53 expression level in mouse blastocysts. Limitations, reasons for caution Though we observed that Fallopian tubal EVs could be internalized by human embryos and improve embryo development morphologically, the subsequent mechanism exploration was conducted using mouse embryos. Whether the stage-specific expression level of miR-21-5p and the effects of miR-21-5p are the same in human embryos remains to be determined. Wider implications of the findings This study showed miRNAs in Fallopian tubal EVs can act as embryonic survival signals, which opens the insight into further explorations to demonstrate the molecular mechanisms during early embryo development, as well as holds the potential to optimize the culture medium used in ART in the future. Trial registration number 2022YFC2702503

Impact of Ionic Liquids on the Physicochemical Behavior of Vesicles.

The effects of two ionic liquids (ILs), 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF4) and 1-butyl-1-methyl pyrrolidinium tetrafluoroborate ([bmp]BF4), on a mixture of phospholipids (PLs) 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC), 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE), and 1,2-dipalmitoyl-sn-glycero-3-phosphoglycerol (DPPG) (6:3:1, M/M/M, 70% PL) in combination with 30 mol % cholesterol (CHOL) were investigated in the form of a solvent-spread monolayer and bilayer (vesicle). Surface pressure (π)-area (A) isotherm studies, using a Langmuir surface balance, revealed the formation of an expanded monolayer, while the cationic moiety of the IL molecules could electrostatically and hydrophobically bind to the PLs on the palisade layer. Turbidity, dynamic light scattering (size, ζ-potential, and polydispersity index), electron microscopy, small-angle X-ray/neutron scattering, fluorescence spectroscopy, and differential scanning calorimetric studies were carried out to evaluate the effects of IL on the structural organization of bilayer in the vesicles. The ILs could induce vesicle aggregation by acting as a "glue" at lower concentrations (<1.5 mM), while at higher concentrations, the ILs disrupt the bilayer structure. Besides, ILs could result in the thinning of the bilayer, evidenced from the scattering studies. Steady-state fluorescence anisotropy and lifetime studies suggest asymmetric insertion of ILs into the lipid bilayer. MTT assay using human blood lymphocytes indicates the safe application of vesicles in the presence of ILs, with a minimal toxicity of up to 2.5 mM IL in the dispersion. These results are proposed to have applications in the field of drug delivery systems with benign environmental impact.

Enhanced current-carrying capability in YBCO coated conductor bilayers for high-field applications

We have investigated the impact of bilayer structures on the critical current density, J c, of YBa2Cu3O6+x (YBCO) coated conductor films, i.e. films grown on buffered metal substrates, under varying temperature and magnetic field conditions. The bilayers consisted of a YBCO layer free of artificial pinning centers and 8 wt% BaZrO3-added (BZO) layer on top, where the thickness percentage of the layers was varied from 0 to 100 %. The results reveal that the bilayer configuration enhances J c at temperatures below 60 K, with a significant improvement in high magnetic fields (5–8 T) and temperatures ≤20 K. The optimal BZO-added layer thickness was found to be approximately 70 %, reaching 80 % at 8 T. Structural examinations indicate improved growth of YBCO and BZO nanorods in the bilayer structure with BZO-added layer thickness ≤80 %. Theoretical model of the bilayer structure considering the layers as two parallel superconductors with different properties was developed. It was found that the model adequately explains all the experimentally observed tendencies, and thus the observed maximum in J c is due to better growth of the BZO-added layer. The study provides valuable insights for designing optimal bilayer structures for diverse applications operating in different temperature and magnetic field regimes.

An Amperometric Type NO2 Sensor Utilizing La0.7Sr0.3MnO3−δ -NiO Composite Sensing Electrode

NO2 is an important pollutant of automobile engines and industrial fuels, making it important to quantitatively monitor and control. An amperometric-type NO2 gas sensor was fabricated using yttria-stabilized zirconia (YSZ) electrolyte with a bi-layered structure and La0.7Sr0.3MnO3−δ -xNiO (LSMO-xNiO, x = 0–0.75) composite sensing electrode (SE) prepared by impregnation method in combination with self-demixing. The samples were characterized using SEM, XRD, and XPS, and their performance as sensors was tested. LSMO-xNiO composite SE particles were formed by de-mixing in the process of treating the precursor at high temperatures and are uniformly dispersed in the YSZ porous backbone. With the increase of NiO content, the SE particles become significantly large. At 450 °C–600 °C, the response currents at a fixed potential have a linear relationship with the NO2 concentrations at 25–700 ppm. Combining stability and sensitivity, the voltage was fixed to −0.25 V. The introduction of NiO into the LSMO sensing electrode effectively improves the performance of the sensor. The sensor based on LSMO-0.5NiO has the highest sensitivity (0.0405 μA/ppm) at 550 °C. Simultaneously, the sensor exhibits good anti-interference ability for CH4, CO2, O2, and NO, but has obvious cross-sensitivity to H2 and NH3. In addition, the response current of the sensor change with the increase of RH.

Efficient evaporation of seawater desalination by novel double-interface evaporator: Photothermal conversion, water transfer and salt-resistant

Interfacial solar-driven water evaporation emerged as an established eco-friendly method for seawater desalination to combat water scarcity, yet the low water evaporation rate and cost-effectiveness limit the practicable application. Herein, we presented a double-interface evaporator with a bilayer structure (BCCu@FC). The upper layer was constructed using carbonized copper-doped biochar (BCCu), which exhibited broadband sunlight absorption and effective photothermal conversion capability for the localized surface plasmon resonance (LSPR) effect. Meanwhile, the lower layer was constructed by felt fabric (FC), which featured a large spatial network structure, guaranteeing sufficient water transportation. Therefore, BCCu@FC exhibited a high photothermal conversion efficiency of 87.05% with a 1.571 kg m-2 h-1 water evaporation rate under 1 sun illumination. Moreover, BCCu@FC further exhibited high stability and salt resistance, showing no significant salt crust formation after continuous operation for 24 h under 3.5 wt% brine. Especially, BCCu@FC could stably work under 21 wt% brine, and the salt crust re-dissolved within 4 h after the cessation of illumination. This facile and universal strategy was anticipated to pave the way for future designs and fabrication of diverse, more efficient, and cost-effective photothermal conversion devices.

High-Q Wireless SAW Sensors Based on AlN/Sapphire Bilayer Structure, Operating at 2.45 GHz Range for High-Temperature Applications

High-Q Wireless SAW Sensors Based on AlN/Sapphire Bilayer Structure, Operating at 2.45 GHz Range for High-Temperature Applications

Microstructural and optoelectronic properties of sputtered Al:ZnO films and Al:ZnO/Cu bilayer structures: Effects of substrate and Cu thickness

In this study, using a multi-source confocal radio frequency magnetron sputtering system, we synthesized aluminum doped zinc oxide (AZO) single layers and AZO/Cu bilayers on glass and crystalline quartz substrates with a constant AZO thickness of 65 nm and variable Cu bottom layers with a thickness of 4–13 nm. The microstructural, morphological, optical, and electrical characteristics of all samples were investigated using a variety of spectroscopic techniques. The X-ray diffraction results show that all films prepared on both substrates have a hexagonal wurtzite crystal structure and exhibit the preferred orientation along the (002) plane with some microstructural variations. The atomic force microscopy images revealed that the thickness of the Cu layer and substrate type greatly affect the films' topography and surface roughness. The transmittance spectra indicate that the single AZO layer on both substrates possess the highest average visible transmission; however, all the samples deposited on glass substrates show greater transmittance than that on quartz. Photoluminescence analysis put into evidence a decrease in ultraviolet emission with Cu thickness for both substrates, with intensities varying according to substrate type. Hall Effect measurements reveal that all samples have n-type conductivity as well as that Cu thickness has a significant impact on their electrical characteristics. Moreover, a higher value of the figure of merit is achieved with the AZO/Cu bilayer structure grown on a glass substrate with 13 nm of Cu layer thickness.

Modulation of Triton X-100 Aqueous Micelle Interface by Ionic Liquid: A Molecular Level Interaction Studied by Time-resolved Fluorescence Spectroscopy

Background: Self-assembly structure is an important area of research for understanding biological systems, owing to its resemblance to the membrane structure of the phospholipid bilayer. In a self-assembly medium, chemical reactions and chemical or physical processes are dramatically different than the bulk phase. Understanding this process in synthesizing self-assembly structures may allow us to explore various biological processes occurring in cell membranes. Objective: The study aimed to understand water dynamics in the TX-100 micellar interface via steady state and a time-resolved fluorescence spectroscopy study. The objective was also to determine the two different ionic liquids (ILs), namely 1-butyl-3-methyl imidazolium tetrafluoroborate ([bmim][BF4]) and 1-decyl-3-methyl imidazolium tetrafluoroborate ([dmim][BF4]), inducing surfactant aggregation changes at the molecular level. Also, the focus was on determining the hydration and its dynamics at the palisade layer of TX-100 micelle in the presence of two different ionic liquids. Methods: Steady state and time-resolved fluorescence spectroscopy have been used to study TX-100 micellar systems. Employing time-resolved spectroscopy, two chemical dynamic processes, solvation dynamics and rotational relaxation dynamics, have been studied to investigate structural changes in TX100 by adding ILs. Solvation dynamics was studied by measuring the time-dependent Stokes shift of the fluorescent probe. From the Stokes shift, time-resolved emission spectra were constructed to quantify the solvation dynamics. Also, using the polarization properties of light, time-resolved anisotropy was constructed to explore the rotation relaxation of the probe molecule. Results: The absorption and emission spectra of C-153 in TX-100 were red-shifted in the presence of both the ILs. Also, the C-153 experienced faster solvation dynamics and rotational relaxation with the addition of both ILs. In our previous study, we observed a significantly increased rate of solvation dynamics with the addition of [bmim][BF4] (J. Phys. Chem. B, 115, 6957-6963) [38]. However, with the addition of the same amount of [dmim][BF4], the IL rate of solvation enhancement was more pronounced than with [bmim][BF4]. The faster solvation and rotational relaxation have been found to be associated with the penetration of more free water at the TX100 micellar stern layer, leading to increased fluidity of the micellar interface. Conclusion: Upon incorporating ILs in TX100 micelle, substantially faster solvation dynamics of water as well as rotational relaxation dynamics of C-153 have been observed. By decreasing surfactant aggregations, [bmim][BF4] ILs facilitated more water molecules approaching the TX-100 micellar phase. On the other hand, [dmim][BF4] ILs comprising mixed micelles induced even more free water molecules at the palisade layer, yielding faster solvation dynamics in comparison to pure TX-100 micelle or TX100 micelle + [bmim][BF4] ILs systems. Time-resolved anisotropy study has also supported the finding and strengthened the solvation dynamics observation.

Enhanced spin pumping in heterostructures of coupled ferrimagnetic garnets

Spin pumping has significant implications for spintronics, providing a mechanism to manipulate and transport spins for information processing. Understanding and harnessing spin currents through spin pumping is critical for the development of efficient spintronic devices. The use of a magnetic insulator with low damping enhances the signal-to-noise ratio in crucial experiments such as spin-torque ferromagnetic resonance (FMR) and spin pumping. A magnetic insulator coupled with a heavy metal or quantum material offers a more straightforward model system, especially when investigating spin-charge interconversion processes to greater accuracy. This simplicity arises from the absence of unwanted effects caused by conduction electrons unlike in ferromagnetic metals. Here, we investigate the spin pumping in coupled ferrimagnetic (FiM) Y3Fe5O12 (YIG)/Tm3Fe5O12 (TmIG) bilayers combined with heavy-metal (Pt) using the inverse spin Hall effect. It is observed that magnon transmission occurs at both of the FiMs FMR positions. The enhancement of spin pumping voltage (Vsp) in the FiM garnet heterostructures is observed. The plausible reason might be the interfacial exchange coupling between FiMs. The modulation of Vsp is achieved by tuning the bilayer structure. Further, the spin mixing conductance for these coupled systems is found to be ≈1018 m−2. Our findings describe a coupled FiM system for the investigation of magnon coupling providing opportunities for magnonic devices.

Streamlining Skin Regeneration: A Ready-To-Use Silk Bilayer Wound Dressing.

Silk proteins have been highlighted in the past decade for tissue engineering (TE) and skin regeneration due to their biocompatibility, biodegradability, and exceptional mechanical properties. While silk fibroin (SF) has high structural and mechanical stability with high potential as an external protective layer, traditionally discarded sericin (SS) has shown great potential as a natural-based hydrogel, promoting cell-cell interactions, making it an ideal material for direct wound contact. In this context, the present study proposes a new wound dressing approach by developing an SS/SF bilayer construct for full-thickness exudative wounds. The processing methodology implemented included an innovation element and the cryopreservation of the SS intrinsic secondary structure, followed by rehydration to produce a hydrogel layer, which was integrated with a salt-leached SF scaffold to produce a bilayer structure. In addition, a sterilization protocol was developed using supercritical technology (sCO2) to allow an industrial scale-up. The resulting bilayer material presented high porosity (>85%) and interconnectivity while promoting cell adhesion, proliferation, and infiltration of human dermal fibroblasts (HDFs). SS and SF exhibit distinct secondary structures, pore sizes, and swelling properties, opening new possibilities for dual-phased systems that accommodate the different needs of a wound during the healing process. The innovative SS hydrogel layer highlights the transformative potential of the proposed bilayer system for biomedical therapeutics and TE, offering insights into novel wound dressing fabrication.

Influence of additional intermediate thick Al layers on the reaction propagation and heat flow of Al/Ni reactive multilayers

This study investigates the effects of sputtering and electron beam evaporation (e‐beam) on the microstructure and reactive properties of Al/Ni reactive multilayers (RML). The intermixing zone, a critical factor influencing reaction kinetics, was characterized using high‐resolution transmission electron microscopy and found to be consistently 3 nm for both fabrication methods. Differential scanning calorimetry revealed that e‐beam samples, with thicker Al layers, exhibited slightly higher total molar enthalpy and maintained high reaction temperatures despite reduced reaction velocities in comparison to sputtered samples. X‐ray diffraction confirmed the formation of both Al3Ni2 and AlNi phases in the e‐beam samples. These findings indicate that while thicker bilayer structures reduce reaction velocity, they keep thermal output and mitigate the impact of intermixing zones, leading to similar total molar enthalpy. This analysis underscores the significance of deposition technique and bilayer thickness in optimizing the performance of Al/Ni RML, offering the possibility to establish different phase formations in thicker RML. It advances the control over the reactive properties of reactive multilayers in their applications, for example reactive bonding.This article is protected by copyright. All rights reserved.

Chiral Supramolecular Self-Assembly Catalysts with Enhanced Metal Ion Interaction for Higher Enantioselectivity.

Understanding the interaction between metal ions as catalytic centers and supramolecular scaffolds as chiral substrates plays an important role in developing chiral supramolecular catalysts with high enantioselectivity. Herein, we found that compared with l-norleucine chiral amphiphile (l-NorC16), l-methionine chiral amphiphile (l-MetC16) with the only heteroatom of S site difference in the hydrophilic group can form a similar supramolecular chiral nanoribbon (NR) with the bilayer structure through the self-assembly approach; yet, the interaction between the Cu(II) ion catalytic centers and supramolecular scaffolds is reinforced, favoring the chirality transfer and therefore enhancing their catalytic enantioselectivity of Diels-Alder reaction from 23% [l-NorC16-NR-Cu(II)] to 78% [l-MetC16-NR-Cu(II)]. Our work demonstrates a new strategy from the perspective of strengthening the metal ion-supramolecular scaffold interaction for the preparation of chiral supramolecular catalysts with good catalytic enantioselectivity.

Chiral versus achiral crystal structures of 4-benzyl-1H-pyrazole and its 3,5-di-amino derivative.

The crystal structures of 4-benzyl-1H-pyrazole (C10H10N2, 1) and 3,5-di-amino-4-benzyl-1H-pyrazole (C10H12N4, 2) were measured at 150 K. Although its different conformers and atropenanti-omers easily inter-convert in solution by annular tautomerism and/or rotation of the benzyl substituent around the C(pyrazole)-C(CH2) single bond (as revealed by 1H NMR spectroscopy), 1 crystallizes in the non-centrosymmetric space group P21. Within its crystal structure, the pyrazole and phenyl aromatic moieties are organized into alternating bilayers. Both pyrazole and phenyl layers consist of aromatic rings stacked into columns in two orthogonal directions. Within the pyrazole layer, the pyrazole rings form parallel catemers by N-H⋯N hydrogen bonding. Compound 2 adopts a similar bilayer structure, albeit in the centrosymmetric space group P21/c, with pyrazole N-H protons as donors in N-H⋯π hydrogen bonds with neighboring pyrazole rings, and NH2 protons as donors in N-H⋯N hydrogen bonds with adjacent pyrazoles and other NH2 moieties. The crystal structures and supra-molecular features of 1 and 2 are contrasted with the two known structures of their analogs, 3,5-dimethyl-4-benzyl-1H-pyrazole and 3,5-diphenyl-4-benzyl-1H-pyrazole.

Bilayer Solar Steam Generator by Co-Gelation Method

The interfacial solar steam generator presents a viable and environmentally conscious solution for generating fresh water from seawater. The interfacial solar steam generator is accomplished through the integration of a photothermal material with a supporting material, resulting in a bilayer structure. In general, the efficiency of achieving a bilayer structure by the coating of a photothermal material on the surface of a substrate is limited. This is due to the potential for separation and variations in coating thickness, which can result in a drop in the rate of evaporation. In this study, a bilayer structure was successfully obtained through the implementation of a co-gelation technique utilizing a biomass-derived substrate, aerogel cellulose, and magnetite (Fe3O4) as photothermal materials. Additionally, we investigate the impact of magnetic fields on the evaporation rate of photothermal materials. The bilayer solar steam generator obtained demonstrates a notable evaporation rate of 1.87 kg.m-2h-1, which is sufficient to meet the daily water requirements of individuals.

Effect of lipid composition on the characteristics of liposomes prepared using the polyol dilution method

Polyol dilution (PD) is a liposome preparation method suitable for mass production in the cosmetics industry. For PD-liposomes, lecithin is the primary material of choice because of its cost advantage. However, despite the importance of understanding the effect of lipid composition on the physicochemical properties of PD-liposomes in terms of formulation design, this has not yet been elucidated. In this study, PD-liposomes were prepared using hydrogenated egg yolk lecithin (EL) and its main components, 1,2-distearoyl-glycero-3-phosphocholine (DSPC), 1,2-dipalmitoyl-glycero-3-phosphocholine (DPPC), and 1,2-distearoyl-glycero-3-phosphoethanolamine (DSPE). The compound 1,3-butylene glycol (BG), which is widely used in the cosmetics industry, was used as a representative polyol. Herein, we aimed to clarify the effect of lipid composition on PD-liposomes. The results showed that the particle size, dispersion stability, shape, and phase state of the lipid bilayer in PD-liposomes could be controlled by changing the composition of the hydrophilic and hydrophobic groups of the lipids. In particular, when PE was added to a system consisting of PC molecules, a significant decrease in particle size, improvement in dispersion stability, and shape changes were observed, indicating a significant effect on the physicochemical properties of the PD-liposomes. In addition, adding BG induced the formation of an interdigitated structure in the lipid bilayer when PC was the only hydrophilic group component; adding even a small amount of PE suppressed the formation of this structure. Furthermore, we confirmed that premixing BG and lipids enhanced the miscibility of different types of lipid molecules. The findings of this study are expected to contribute to the design of highly functional PD-liposomes by enabling the selection and design of appropriate lipid compositions for practical applications.

Modulating lipid bilayer permeability and structure: Impact of hydrophobic chain length, C-3 hydroxyl group, and double bond in sphingosine

Sphingosine, an amphiphilic molecule, plays a pivotal role as the core structure of sphingolipids, essential constituents of cell membranes. Its unique capability to enhance the permeability of lipid membranes profoundly influences crucial life processes. The molecular structure of sphingosine dictates its mode of entry into lipid bilayers and governs its interactions with lipids, thereby determining membrane permeability. However, the incomplete elucidation of the relationship between the molecular structure of sphingosine and the permeability of lipid membranes persists due to challenges associated with synthesizing sphingosine molecules. A series of sphingosine-derived molecules, featuring diverse hydrophobic chain lengths and distinct headgroup structure, were meticulously designed and successfully synthesized. These molecules were employed to investigate the permeability of large unilamellar vesicles, functioning as model lipid bilayers. With a decrease in the hydrophobic chain length of sphingosine from C15 to C11, the transient leakage ratio of vesicle contents escalated from ∼ 13 % to ∼ 28 %. Although the presence of double bond did not exert a pronounced influence on transient leakage, it significantly affected the continuous leakage ratio. Conversely, modifying the chirality of the C-3 hydroxyl group gives the opposite result. Notably, methylation at the C-3 hydroxyl significantly elevates transient leakage while suppressing the continuous leakage ratio. Additionally, sphingosines that significantly affect vesicle permeability tend to have a more pronounced impact on cell viability. Throughout this leakage process, the charge state of sphingosine-derived molecule aggregates in the solution emerged as a pivotal factor influencing vesicle permeability. Fluorescence lifetime experiments further revealed discernible variations in the effect of sphingosine molecular structure on the mobility of hydrophobic regions within lipid bilayers. These observed distinctions emphasize the impact of molecular structure on intermolecular interactions, extending to the microscopic architecture of membranes, and underscore the significance of subtle alterations in molecular structure and their associated aggregation behaviors in governing membrane permeability.

Quadrupolar and dipolar excitons in symmetric trilayer heterostructures: insights from first principles theory

Excitons in van der Waals heterostructures come in many different forms. In bilayer structures, the electron and hole may be localized on the same layer or they may be separated forming an interlayer (IL) exciton with a finite out-of-plane dipole moment. Using first principles calculations, we investigate the excitons in a symmetric WS2/MoS2/WS2 heterostructure in the presence of a vertical electric field. The excitons exhibit a quadratic Stark shift for low field strengths and a linear Stark shift for stronger fields. This behavior is traced to the coupling of IL excitons with opposite dipole moments, which lead to the formation of quadrupolar excitons at small fields. The formation of quadrupolar excitons is determined by the relative size of the electric field-induced splitting of the dipolar excitons and the coupling between them given by the hole tunneling across the MoS2 layer. For the inverted structure, MoS2/WS2/MoS2, the dipolar excitons are coupled by electron tunneling across the WS2 layer. Because this effect is much weaker, the resulting quadrupolar excitons are more fragile and break at a weaker electric field.

Detection of Multi-Layered Bond Delamination Defects Based on Full Waveform Inversion.

This study aimed to address the challenges encountered in traditional bulk wave delamination detection methods characterized by low detection efficiency. Additionally, the limitations of guided wave delamination detection methods were addressed, particularly those utilizing reflected waves, which are susceptible to edge reflections, thus complicating effective defect extraction. Leveraging the full waveform inversion algorithm, an innovative approach was established for detecting delamination defects in multi-layered structures using ultrasonic guided wave arrays. First, finite element modeling was employed to simulate guided wave data acquisition by a circular array within an aluminum-epoxy bilayer structure with embedded delamination defects. Subsequently, the full waveform inversion algorithm was applied to reconstruct both regular and irregular delamination defects. Analysis results indicated the efficacy of the proposed approach in accurately identifying delamination defects of varying shapes. Furthermore, an experimental platform for guided wave delamination defect detection was established, and experiments were conducted on a steel-cement bilayer structure containing an irregular delamination defect. The experimental results validated the exceptional imaging precision of our proposed technique for identifying delamination defects in multi-layered boards. In summary, the proposed method can accurately determine both the positions and sizes of defects with higher detection efficiency than traditional pulse-echo delamination detection methods.