Nanoscale Morphology Research Articles

Preparation of Black pepper (Piper nigrum L.) essential oil nanoparticles and its antitumor activity on triple negative breast cancer in vitro.

The active compounds isolated from Black pepper have anticancer effects, but the bioactivity of Black pepper essential oil (BP-EO) is rarely studied. BP-EO has poor stability and a suitable dose form should be prepared for in vivo delivery. Triple negative breast cancer (TNBC) has attracted more and more attention due to its high mitotic index, high metastasis rate and poor prognosis. In this study, the composition of BP-EO was analyzed by gas chromatography-mass spectrometry (GC-MS), and nanoparticles (NPs) loaded with BP-EO were prepared by nanoprecipitation method using Eudragit L100 as a carrier. We investigated the preparation, characterization, stability and in vitro release of nanoparticles. MTT assay, cell wound healing, Transwell invasion assay and Western blot were used to study the anti-tumor effect and mechanism of MDA-MB-231 cells. The GC-MS analysis identified a total of 33 compounds among which alkenes account for 63.55%. The prepared BP-EO NPs exhibited nanoscale morphology, good stability and pH-responsive and sustained release character which is suitable for in vivo delivery. BP-EO NPs significantly inhibited the proliferation, migration and invasion of MDA-MB-231 cells. Furthermore, BP-EO NPs significantly inhibited the expressions of Wnt and β-catenin and significantly activated the expression of GSK-3β in MDA-MB-231 cells. Therefore, BP-EO NPs prepared in this study provide a new effective strategy for the treatment of TNBC. PRACTICAL APPLICATIONS: Black pepper is rich in essential oil and has excellent antioxidant and antibacterial activities. However, the anti-tumor activity of BP-EO has not been studied. In this study, we found that BP-EO has excellent anticancer activity. To achieve effective encapsulation of black pepper essential oil and an excellent anti-triple negative breast cancer activity, nanoparticles loaded with BP-EO were prepared using Eudragit L100 as the carrier by the nanoprecipitation method. The in vitro study revealed that BP-EO NPs inhibited proliferation, migration and invasion of MDA-MB-231 cells via inhibiting the Wnt/β-Catenin signaling pathway. This study provides new ideas and innovations for the treatment of invasive triple negative breast cancer in the future. At the same time, we will further reveal the application potential, pharmacokinetic characteristics and precise mechanism of BP-EO NPs in vivo in subsequent studies.

Investigating the morphology of bulk heterojunctions by laser photoemission electron microscopy

The nanoscale morphology of bulk heterojunctions is highly important for the charge dissociation and transport in organic solar cells and ultimately defines the performance of the cell. The visualization of this nano-morphology in terms of domain size and polymer orientation in a fast and straightforward way is therefore of great interest to evaluate the suitability of a film for efficient solar cells. Here, we demonstrate that the morphology of different blends of poly(3-hexylthiophene-2,5-diyl) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) can be imaged and analyzed by employing photoemission electron microscopy.

Control of Ca2+ signals by astrocyte nanoscale morphology at tripartite synapses.

Much of the Ca2+ activity in astrocytes is spatially restricted to microdomains and occurs in fine processes that form a complex anatomical meshwork, the so-called spongiform domain. A growing body of literature indicates that those astrocytic Ca2+ signals can influence the activity of neuronal synapses and thus tune the flow of information through neuronal circuits. Because of technical difficulties in accessing the small spatial scale involved, the role of astrocyte morphology on Ca2+ microdomain activity remains poorly understood. Here, we use computational tools and idealized 3D geometries of fine processes based on recent super-resolution microscopy data to investigate the mechanistic link between astrocytic nanoscale morphology and local Ca2+ activity. Simulations demonstrate that the nano-morphology of astrocytic processes powerfully shapes the spatio-temporal properties of Ca2+ signals and promotes local Ca2+ activity. The model predicts that this effect is attenuated upon astrocytic swelling, hallmark of brain diseases, which we confirm experimentally in hypo-osmotic conditions. Upon repeated neurotransmitter release events, the model predicts that swelling hinders astrocytic signal propagation. Overall, this study highlights the influence of the complex morphology of astrocytes at the nanoscale and its remodeling in pathological conditions on neuron-astrocyte communication at so-called tripartite synapses, where astrocytic processes come into close contact with pre- and postsynaptic structures.

Polycarbonate/Titania Composites Incorporating TiO2 with Different Nanoscale Morphologies for Enhanced Environmental Stress Cracking Resistance in Dioctyl Phthalate.

Polycarbonate (PC) is susceptible to environmental stress cracking (ESC) when the conditions of pre-strain and presence of fluid with a compatible solubility index are both prevalent. One approach to counter this involves using nanoscale fillers to bridge the propagating microcracks, thus, effectively inhibiting impending failure. In this work, we report incorporation of titania (TiO2) with different nanoscale morphologies into polycarbonate matrix to assess its effect on ESC resistance against dioctyl phthalate (DOP). Using a hydrothermal process with a NaOH/Ti molar ratio of 72, TiO2 nanostructures were produced containing nanosheets with large surface area and nanotubes having typical diameter and length values of 15–20 nm and a few hundred nanometers, respectively. PC/TiO2 composites were fabricated with up to 0.5 weight percent of TiO2 nanoparticles (NPs), nanowires (NWs), or hybrid nanostructures (HNs). ESC tests were conducted by exposing test coupons to DOP oil at different temperatures and pre-strain conditions. The results showed that, under identical test conditions, while as-received PC grade exhibited complete fracture in ~3.1 h, PC/TiO2-0.05HN composite took ~70 h to fail via surface cracking. SEM examination of the fracture surface revealed that homogeneous dispersion and efficient load-bearing capability of TiO2 nanotubes and nanosheets impeded localized crack propagation by bridging the gap between the PC matrix segments. Liquid nitrogen fracture of the PC/TiO2 composite further confirmed the critical role of TiO2 hybrid nanostructures towards improvement in ESC resistance of PC matrix composites.

Stable nanoreactors for material fabrication using the aggregation of fluorinated ionic liquid surfactants in ionic liquid solvents

The design of thermostable and efficient self-assembly nanoreactors is highly desirable for the fabrication of nanomaterials. Benefiting from the tunable properties and nonvolatility of ionic liquids (IL), IL-in-IL self-assembly systems show a flexible structure and thermostability under extreme conditions. Inspired by this hypothesis, stronger hydrophobic fluorinated ILs are expected to fabricate nonvolatile IL-in-IL self-assembly systems. In this work, two series of fluorinated ILs were synthesized and characterized by NMR, FTIR, DSC, and TGA. Then, the aggregation of these fluorinated ILs in protic and aprotic IL solvents was studied by surface tension and 19F NMR methods. The microstructure of these IL-in-IL aggregation systems was characterized by DLS and SAXS. The fluorinated ILs exhibit excellent surface activity even in aprotic ILs. Furthermore, protic ILs display superior ability to promote the self-assembly of ILs surfactants. These IL-in-IL aggregation systems display the typical morphology of ellipsoidal or multilayer spherical micelles with diameters of approximately 10 nm ∼ 60 nm. A typical IL-in-IL aggregation system was proposed as an efficient nanoreactor to prepare nanoscale MOFs without using any volatile organic solvents or autoclaving. The synthesized HKUST-1 exhibits larger surface areas and nanoscale morphology by XRD, SEM, TEM, BET, and XPS characterization. The results presented in this study offer key information to design new thermostable IL-based colloidal systems and their applications.

Self-assembly of C60 on a ZnTPP/Fe(001)-p(1 × 1)O substrate: observation of a quasi-freestanding C60 monolayer.

Fullerene (C60) has been deposited in ultrahigh vacuum on top of a zinc tetraphenylporphyrin (ZnTPP) monolayer self-assembled on a Fe(001)–p(1 × 1)O substrate. The nanoscale morphology and the electronic properties of the C60/ZnTPP/Fe(001)–p(1 × 1)O heterostructure have been investigated by scanning tunneling microscopy/spectroscopy and ultraviolet photoemission spectroscopy. C60 nucleates compact and well-ordered hexagonal domains on top of the ZnTPP buffer layer, suggesting a high surface diffusivity of C60 and a weak coupling between the overlayer and the substrate. Accordingly, work function measurements reveal a negligible charge transfer at the C60/ZnTPP interface. Finally, the difference between the energy of the lowest unoccupied molecular orbital (LUMO) and that of the highest occupied molecular orbital (HOMO) measured on C60 is about 3.75 eV, a value remarkably higher than those found in fullerene films stabilized directly on metal surfaces. Our results unveil a model system that could be useful in applications in which a quasi-freestanding monolayer of C60 interfaced with a metallic electrode is required.

Insights into Heterogeneous Catalysts under Reaction Conditions by In Situ/Operando Electron Microscopy

AbstractThe advancement of clean energy and environment depends strongly on the development of efficient catalysts in a wide range of heterogeneous catalytic reactions, which has benefited from transmission electron microscopic techniques in determining the atomic‐scale morphologies and structures. However, it is the morphology and structure under the catalytic reaction conditions that determine the performance of the catalyst, which has captured a surge of interest in developing and applying in situ/operando transmission electron microscopic techniques in heterogeneous catalysis. The major theme of this review is to highlight some of the most recent insights into heterogeneous catalysts under the relevant reaction conditions using in situ/operando transmission electron microscopic techniques. Rather than a comprehensive overview of the basic principles of in situ/operando techniques, this review focuses on the insights into the atomic‐scale/nanoscale details of various catalysts ranging from single‐component to multicomponent catalysts under heterogeneous catalytic, electrocatalytic, and photocatalytic reaction conditions involving both gas–solid and liquid–solid interfaces. This focus is coupled with discussions of the correlation of the atomic, molecular, and nanoscale morphology, composition, and structure with the catalytic properties under the reaction conditions, shining light on the challenges and opportunities in design of nanostructured catalysts for clean and sustainable energy applications.

Effects of Nanoscale Morphology on Optical Properties of Photoluminescent Polymer Optical Fibers.

Bicomponent photoluminescent polymer optical fibers (PL-POFs) have been melt-spun and in-situ drawn to different extents. The results suggest that scattering in the sheath can effectively increase the photoluminescent dye excitation probability in the fiber core. The core/sheath PL-POFs are made of a semi-crystalline fluoropolymer sheath of low refractive index (RI) and an amorphous cycloolefin polymeric core of high RI, which is doped with a luminescent dye. The axial light emission, as well as the guiding attenuation coefficients of the core/sheath PL-POFs, have been measured using a side-illumination set-up. The incident blue laser is down-converted to red light, which is re-emitted and partially guided by the core. The axial light emission is measured at the fiber tip as a function of the distance from the illumination position to the integrating sphere. It is demonstrated that the presence of a semi-crystalline sheath significantly enhances the axial light emission and that it also lowers the attenuation coefficient, compared to the emission and guiding properties of PL core-only fibers. Additionally, the attenuation coefficient has been found to be lower in more strongly drawn PL-POFs. Wide-angle X-ray diffraction and small-angle X-ray scattering experiments reveal structural differences in differently drawn PL-POFs that can be linked to the observed differences in the optical properties.

Nanoscale Morphological Characterization of Coordinated Binder and Solid Electrolyte Interphase in Silicon-Based Electrodes for Li-Ion Batteries.

The physical crosslinking of polymeric binders through coordination chemistry significantly improves the electrochemical performance of silicon-based negative electrodes. Scanning electron microscopy coupled with energy dispersive X-ray spectroscopy is used to probe the nanoscale morphology of such electrodes. This technique reveals the homogeneous coordination of carboxylated binder with Zn cations and its layering on the silicon surface. The solid electrolyte interphase (SEI) formed after the first cycle is denser with Zn-coordinated binder and preferentially observed on binder-depleted zones. The superiority of coordinated binders can be attributed to their capacity to better stabilize the electrode and the SEI layer due to improved mechanical properties. This results in a lower SEI impedance, a higher first cycle coulombic efficiency, and a 40% improvement of capacity retention after 50 cycles for highly loaded electrodes of over 6mAhcm-2 .

Fingerprinting the Hidden Facets of Plasmonic Nanocavities.

The optical properties of nanogap plasmonic cavities formed by a NanoParticle-on-Mirror (NPoM, or patch antenna) are determined here, across a wide range of geometric parameters including the nanoparticle diameter, gap refractive index, gap thickness, facet size and shape. Full understanding of the confined optical modes allows these nanocavities to be utilized in a wide range of experiments across many fields. We show that the gap thickness t and refractive index n are spectroscopically indistinguishable, accounted for by a single gap parameter G = n/t0.47. Simple tuning of mode resonant frequencies and strength is found for each quasi-normal mode, revealing a spectroscopic “fingerprint” for each facet shape, on both truncated spherical and rhombicuboctahedral nanoparticles. This is applied to determine the most likely nanoscale morphology of facets hidden below each NPoM in experiment, as well as to optimize the constructs for different applications. Simple scaling relations are demonstrated, and an online tool for general use is provided.

Defect Engineering via Copper Doping on Oxygen‐Deficient Manganese Oxide for Durable Aqueous Zinc‐Ion Battery

Aqueous Zn‐ion batteries (ZIBs) have triggered an astounding research surge because of their high safety, affordability, and impressive electrochemical properties. However, the smooth implementation of this promising technology is hindered by severe structural degradation and sluggish reaction kinetics of the cathode materials. Here, the defect engineering is demonstrated by the substitution doping of Cu2+ in layered δ‐MnO2 to boost the electrochemical reactivity for Zn‐ion storage. Benefited from the nanoscale morphology and oxygen‐deficient structural features, this Zn/MnO2 battery is able to deliver a high reversible capacity of 296.8 mAh g−1 with a capacity retention of 94.9% over 120 cycles (at 0.1 A g−1) and a desirable energy density of 441 Wh kg−1, as well as an ultra‐long cycle life up to 6000 cycles, which is also intensively associated with the facilitated Zn2+ diffusion and charge transfer rates after the Cu2+ dopants, based on the electrochemical kinetics analysis. The effortless but effective defect engineering arising from element doping can provide significant enlightenment to design high‐performance cathode materials for ZIBs.

Effect of annealing on mechanical properties and thermal stability of ZrCu/O nanocomposite amorphous films synthetized by pulsed laser deposition

Binary ZrCu nanocomposite amorphous films are synthetized by pulsed laser deposition (PLD) under vacuum (2 × 10−3 Pa) and 10 Pa He pressure, leading to fully amorphous compact and nanogranular morphologies, respectively. Then, post-thermal annealing treatments are carried out to explore thermal stability and crystallization phenomena together with the evolution of mechanical properties. Compact films exhibit larger thermal stability with partial crystallization phenomena starting at 420 °C, still to be completed at 550 °C, while nanogranular films exhibit early-stage crystallization at 300 °C and completed at 485 °C. The microstructural differences are related to a distinct evolution of mechanical properties and residual stress, with compact TFMGs showing the highest values of Young’s modulus (157 GPa), hardness (12 GPa), strain rate sensitivity (0.096), and local residual stress (+691 MPa) upon annealing at 550 °C, while nanogranular films reach the maximum values of mechanical properties at 485 °C followed by relaxation at higher temperatures due to complete crystallization. We show that PLD in combination with post-thermal annealing can generate different families of amorphous films with varying nanoscale morphologies, resulting in tunable mechanical properties and thermal stability, which can thus be used for designing novel film configurations for different fields of application.

Designing Nanostructured 3D Printed Materials by Controlling Macromolecular Architecture

AbstractNanostructured polymeric materials play important roles in many advanced applications, however, controlling the morphologies of polymeric thermosets remains a challenge. This work uses multi‐arm macroCTAs to mediate polymerization‐induced microphase separation (PIMS) and prepare nanostructured materials via photoinduced 3D printing. The characteristic length scale of microphase‐separated domains is determined by the macroCTA arm length, while nanoscale morphologies are controlled by the macroCTA architecture. Specifically, using 2‐ and 4‐ arm macroCTAs provides materials with different morphologies compared to analogous monofunctional linear macroCTAs at similar compositions. The mechanical properties of these nanostructured thermosets can also be tuned while maintaining the desired morphologies. Using multi‐arm macroCTAs can thus broaden the scope of accessible nanostructures for extended applications, including the fabrication of actuators and potential drug delivery devices.

Designing Nanostructured 3D Printed Materials by Controlling Macromolecular Architecture.

Nanostructured polymeric materials play important roles in many advanced applications, however, controlling the morphologies of polymeric thermosets remains a challenge. This work uses multi‐arm macroCTAs to mediate polymerization‐induced microphase separation (PIMS) and prepare nanostructured materials via photoinduced 3D printing. The characteristic length scale of microphase‐separated domains is determined by the macroCTA arm length, while nanoscale morphologies are controlled by the macroCTA architecture. Specifically, using 2‐ and 4‐ arm macroCTAs provides materials with different morphologies compared to analogous monofunctional linear macroCTAs at similar compositions. The mechanical properties of these nanostructured thermosets can also be tuned while maintaining the desired morphologies. Using multi‐arm macroCTAs can thus broaden the scope of accessible nanostructures for extended applications, including the fabrication of actuators and potential drug delivery devices.

Vapor Barrier Properties of Cold Plasma Treated Corn Starch Films

The development and efficient production of effective bioplastics is a hot topic, required to face up to the issue of the difficult disposal of plastics derived from oil. Among the different natural sources of bioplastics, starch is one of the most promising. However, for most applications, the proper mastering of the surface properties of bioplastic is necessary. We report about the surface modification of extruded corn starch films by means of cold plasma based on helium (He) and hexamethyldisiloxane (HMDSO). The differently treated surfaces were functionally characterized in wettability and water absorption. The nanoscale morphology was assessed by scanning electron microscopy and atomic force microscopy. The obtained images were analyzed by advanced figures describing both texture and amplitude parameters, including fractal behavior. The combined treatment (He/HMDSO) resulted in more homogeneous films with smaller, better-distributed grains compared to the case wherein He was not used. Despite the different morphologies observed, starch coated by HMDSO alone and by He/HMDSO presented similar hydrophobic character, with contact angles higher than 110°. Plasma treatment with HMDSO and He/HMDSO resulted in a significant reduction of absorbed water content without reduction of water vapor permeability. The nanotexture of the films did not present statistically significant differences, in terms of spatial complexities, dominant spatial frequencies, homogeneous void distribution, and surface percolation.

Quantifying the atomistic free-volume morphology of materials with graph theory

We introduce a new computational methodology for the identification and characterization of free volume within/around atomistic configurations. This scheme employs a three-stage workflow, by which spheres are iteratively grown inside of voxels, and ultimately converted to planar graphs, which are then characterized via a graph-based order parameter. Our approach is computationally efficient, physically intuitive, and universally transferable to any material system. Validation of our methodology is performed on several sets of materials problems: (1) classification of unique free volumes in various crystal phases, (2) autonomous detection and classification of complex surface defects during epitaxial growth simulations, (3) characterization of free volume defects in metals/alloys, and (4) quantification of the spatio-temporal behavior of nano-scale free volume morphologies as a function of both temperature and free-volume size. Our method accurately identifies and characterizes unique free volumes over a multitude of systems and length scales, indicating its potential for future use in understanding the relationship between free volume morphology and material properties under both static and dynamic conditions.

Nano- to macro-scale control of 3D printed materials via polymerization induced microphase separation

Although 3D printing allows the macroscopic structure of objects to be easily controlled, controlling the nanostructure of 3D printed materials has rarely been reported. Herein, we report an efficient and versatile process for fabricating 3D printed materials with controlled nanoscale structural features. This approach uses resins containing macromolecular chain transfer agents (macroCTAs) which microphase separate during the photoinduced 3D printing process to form nanostructured materials. By varying the chain length of the macroCTA, we demonstrate a high level of control over the microphase separation behavior, resulting in materials with controllable nanoscale sizes and morphologies. Importantly, the bulk mechanical properties of 3D printed objects are correlated with their morphologies; transitioning from discrete globular to interpenetrating domains results in a marked improvement in mechanical performance, which is ascribed to the increased interfacial interaction between soft and hard domains. Overall, the findings of this work enable the simplified production of materials with tightly controllable nanostructures for broad potential applications.

Myriophyllum spicatum Leaves: Aerophily for Gas Collection and Transportation in Water.

The unique living environment of aquatic plants makes them produce many fantastic properties different from land ones. For instance, the leaves of Myriophyllum spicatum show excellent hydrophobicity and aerophily characteristics. In this paper, the abundant morphological structure, composition, and aerophily properties of Myriophyllum spicatum leaves are revealed. The contact angle of the leaf surface can reach 122° in air, exhibiting wonderful gas collection ability under water. The results showed that the aerophily of the leaves is attributed to the multistage micro-nanostructure and waxy layer on the surface. The gas transportation toward the tips of leaves is based on the void gradient formed by the nanoscale morphology at different growth stages and the buoyancy as well. These features provide bionic experience for gas collection, bubble transportation, and liquid resistance reduction in water environments.

Modulating the nanoscale morphology on carboxylate-pyrazine containing terpolymer toward 17.8% efficiency organic solar cells with enhanced thermal stability

It had been commonly accepted in the organic photovoltaic (OPV) community that subtle variations in the molecular structure of active layer materials would cause profound impacts on their aggregating structure and blend morphology and therefore the performance of such polymer solar cells (PSCs). Herein, we employed an electron-deficient building block 3,6-dithiophenyl-2-carboxylate pyrazine (DTCPz) for constructing one series of promising donor terpolymers of PMZ1, PMZ2, and PMZ3, respectively, gaining their relatively lower-lying highest occupied molecular orbital (HOMO) energy levels, more closed π-π stacking and enhanced crystallinity in thin films, and lower miscibility with acceptor Y6, in comparison with their parent polymer counterpart (namely PM6). Reaching DTCPz moieties up to 20% (mol/mol%) in its terpolymer composition, the resulting polymer (PMZ2) achieved more favorable phase separation with improved exciton dissociation, and charge transport and extraction. As a result, an outstanding fill factor of 77.2% and a promising power conversion efficiency of 17.8 % was achieved. Moreover, the corresponding device shows better thermal stability over the PM6-based one. This work suggests a facile method for significantly improving the thin film morphology of the active-layer materials via fine-tuning the chemical structure of electron-deficient units on the backbone of the wide bandgap donor polymer, therefore achieving enhanced photovoltaic performance and thermal stability for practical applications.

2D Nanomaterials: A Potent Antiviral Agent

Abstract: In this study, we have thoroughly studied the potentiality of 2D nanomaterials against different viruses. The extremely high surface-volume ratio is beneficial for surface-related reactions like catalysis, this provides flexibility and other intrinsic properties. The antimicrobial activity of nanomaterials is well established. Here we go through different 2D nanomaterials, showing a variety of antiviral actions through the generation of ROS and oxidative stress. The antiviral action of nanosheets has been attributed to their negative surface charge and the presence of a layered nanoscale morphology with sharp edges and corners. Due to their strong electrostatic activity with envelope and non-envelop viruses the sharp edge causes physical damage, and protein disruption causes virus damage. 2D nanomaterials have a wide opening in the field of research and development. Keywords: Nanomaterials, Antiviral agent, 2D nanoparticles, Nanosheets, Graphene