Nanoscale Structures Research Articles

Novel Approach for Biosensor-Based Imaging of Cysteine Levels in Ischemeic Heart Disease: Insights from Preclinical Models and Human Samples.

Cardiovascular diseases (CVDs) pose a serious threat to human health, with atherosclerosis being a leading cause of heart disease and stroke. Elevated cysteine (Cys) levels have been closely linked to an increased risk of cardiovascular diseases, underscoring its significance in cardiovascular health. However, current detection methods for cysteine in serum and atherosclerotic plaques present challenges in sensitivity, specificity, dynamic monitoring, and invasiveness. The development of more sensitive, specific, and noninvasive assays is needed to enable accurate monitoring of cysteine levels. This study introduces the development and characterization of Cys-NPs, a sensitive and selective tool for imaging cysteine in foam cells and atherosclerotic mice. Encapsulation of the HD-probe using DSPE-PEG to obtain Cys-NPs effectively reduced interference from glutathione (GSH), leading to successful preparation and validation of Cys-NPs's nanoscale structure. At the same time, Cys-NPs was able to use the differences in Hcy and Cys concentrations in vivo to better assess Cys levels in vivo. In vitro and in vivo studies demonstrated Cys-NPs's effective imaging of cysteine in foam cells and atherosclerotic mice, highlighting its potential for noninvasive assessment of cysteine levels in ischemic heart disease research and clinical practice.

Molecular Dynamics Simulations Elucidate the Molecular Organization of Poly(beta-amino ester) Based Polyplexes for siRNA Delivery.

Cationic polymers are known to efficiently deliver nucleic acids to target cells by encapsulating the cargo into nanoparticles. However, the molecular organization of these nanoparticles is often not fully explored. Yet, this information is crucial to understand complex particle systems and the role influencing factors play at later stages of drug development. Coarse-grained molecular dynamics (CG-MD) enables modeling of systems that are the size of real nanoparticles, providing meaningful insights into molecular interactions between polymers and nucleic acids. Herein, the particle assembly of variations of an amphiphilic poly(beta-amino ester) (PBAE) with siRNA was simulated to investigate the influence of factors such as polymer lipophilicity and buffer conditions on the nanoparticle structure. Simulations were validated by wet lab methods including nuclear magnetic resonance (NMR) and align well with experimental findings. Therefore, this work emphasizes that CG-MD simulations can provide underlying explanations of experimentally observed nanoparticle properties by visualizing the nanoscale structure of polyplexes.

MiR-23b-3p, miR-126-3p and GAS5 delivered by extracellular vesicles inhibit breast cancer xenografts in zebrafish

BackgroundExtracellular vesicles (EVs) are a group of nanoscale cell-derived membranous structures secreted by all cell types, containing molecular cargoes involved in intercellular communication. EVs can be used to mimic “nature’s delivery system” to transport nucleic acids, peptides, lipids, and metabolites to target recipient cells. EVs offer a range of advantages over traditional synthetic carriers, thus paving the way for innovative drug delivery approaches that can be used in different diseases, including cancer. Here, by using breast cancer (BC) cells treated with the multi-kinase inhibitor sorafenib, we generated EVs enriched in specific non-coding RNAs (miR-23b-3p, miR-126-3p, and the long ncRNA GAS5) and investigated their potential impact on the aggressive properties of the BC in vitro and in vivo using zebrafish.MethodsEVs were collected from 4 different BC cell lines (HCC1937, MDA-MB-231, MCF-7, and MDA-MB-453) and characterized by western blotting, transmission electron microscopy and nanoparticle tracking analysis. Levels of encapsulated miR-23b-3p, miR-126-3p, and GAS5 were quantified by ddPCR. The role of the EVs as carriers of ncRNAs in vivo was established by injecting MDA-MB-231 and MDA-MB-453 cells into zebrafish embryos followed by EV-based treatment of the xenografts with EVs rich in miR-23b-3p, miR-126-3p and GAS5.ResultsddPCR analysis revealed elevated levels of miR-23b-3p, miR-126-3p, and GAS5, encapsulated in the EVs released by the aforementioned cell lines, following sorafenib treatment. The use of EVs as carriers of these specific ncRNAs in the treatment of BC cells resulted in a significant increase in the expression levels of the three ncRNAs along with the inhibition of cellular proliferation in vitro. In vivo experiments demonstrated a remarkable reduction of xenograft tumor area, suppression of angiogenesis, and decreased number of micrometastasis in the tails after administration of EVs enriched with these ncRNAs.ConclusionsOur study demonstrated that sorafenib-induced EVs, enriched with specific tumor-suppressor ncRNAs, can effectively inhibit the aggressive BC characteristics in vitro and in vivo. Our findings indicate an alternative way to enrich EVs with specific tumor-suppressor ncRNAs by treating the cells with an anticancer drug and support the development of new potential experimental molecular approaches to target the aggressive properties of cancer cells.

The size dependence of flexoelectricity at nanocracks

The flexoelectric effect is an electro-mechanical coupling between strain gradients and the electric polarization, and it is especially significant for nanoscale structures. Since the strain gradient scales up with the decrease in the sample's feature size, the flexoelectric effect is size dependent. Due to the stress concentration, large strain gradients can be found at the crack tip and result in significant flexoelectric effect. However, for micro- or nanoscale cracks, it is still not clear how the flexoelectric effect changes with the size of cracks. In practice, the crack tip has finite radius. So, in addition to the crack length, the crack tip radius is also one of the geometric parameters describing the size of nanocracks. In this work, using our collocation mixed finite element method (CMFEM), we study the size dependence of flexoelectricity around nanocracks through these two parameters. Numerical simulation results indicate that stronger flexoelectric field can be formed around the tip of cracks with either larger crack length or smaller tip radius. We also analyze the interplay of the crack length and the tip radius and show how the crack tip flexoelectric field varies when both of these two parameters are changing.

Modulating phase segregation during spin-casting of fullerene-based polymer solar-cell thin films upon minor addition of a high-boiling co-solvent

The impact of additives on the nanoscale structures of spin-cast polymer composite films, particularly in polymer solar cells, is a topic of significant interest. This study focuses on the blend film comprising poly(thieno[3,4-b]thiophene-alt-benzodithiophene) (PTB7) and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM), exploring how additives like 1,8-diiodooctane (DIO) influence the film structures spin-cast from chlorobenzene solution. Combined results of specular X-ray and neutron reflectivity, grazing-incidence small- and wide-angle X-ray scattering (GISAXS and GIWAXS), and X-ray photoelectron spectroscopy indicate that DIO could significantly enhance the dispersion of PC71BM and reduce composition inhomogeneity in the film. Time-resolved GISAXS–GIWAXS with 100 ms resolution further captures a rapid spinodal decomposition of the mixture within 1 s in the constant-evaporation stage of spin-casting. Further combined with parallel analysis of time-resolved UV–Vis reflectance, these findings reveal that DIO mitigates the spinodal decomposition process by accelerating solvent evaporation, which, in turn, decelerates phase segregation, leading to a nucleation-driven process. These observations provide mechanistic insights into the role of additives in controlling the nanostructural evolution of spin-cast films by altering the kinetics of solvent evaporation and phase separation during the spin-coating process.

Nanodomains and Their Temperature Dependence in a Phosphonium-Based Ionic Liquid: A Single-Molecule Tracking Study.

Ionic liquids (ILs) exhibit a unique nanoscale structure (i.e., nanodomains) characterized by their organization into distinct domains. We present evidence of nanodomains in trihexyl(tetradecyl)phosphonium chloride, [P66614][Cl], using single-molecule tracking (SMT) and the maximum entropy method (MEM) to analyze single-molecule trajectories. The diffusion properties of ATTO 647N were assessed as the temperature of [P66614][Cl] increased from 20 °C (4020 cP), 35 °C (1239 cP), 45 °C (599 cP) to 50 °C (439 cP). The MEM analysis revealed a distinct two-population distribution of diffusion coefficients representing nanodomains in [P66614][Cl] at 20 °C (4020 cP). The slow population accounts for 16%, with a diffusion coefficient of 0.104 μm2/s, while the fast population constitutes 84% with a diffusion coefficient of 0.634 μm2/s. Two diffusing populations were also measured for the chemically different probes ATTO 647N, DiD, and Nile Blue chloride in [P66614][Cl] at 20 °C. In contrast, only a single fast population was measured in [P66614][Cl] at 50 °C. At a similar viscosity (640 cP) but a lower temperature of 20 °C, trihexyl(tetradecyl)phosphonium bis[(trifluoromethyl)-sulfonyl]imide, [P66614][NTf2], also showed only a single diffusing population. The elimination of the slow population and the presence of a single diffusing population in [P66614][Cl] as the temperature increases and the viscosity decreases is consistent with liquid-liquid phase separation (LLPS) as a mechanism of nanodomain formation. In addition, the measurement of two diffusing populations for three fluorophores with different chemical structures is also consistent with a physical mechanism, and not a chemical mechanism, for nanodomain formation.

Nanoindentation of nano-SiC/Si hybrid crystals and AlN, AlGaN, GaN, Ga<sup>2</sup>O<sup>3</sup> thin films on nano-SiC/Si

The review presents systematization and analysis of experimental data on nanoindentation (NI) of a whole class of new materials – wide-gap AlN, GaN, AlGaN and β-Ga2O3 heterostructures formed on a hybrid substrate of a new SiC/Si type, which were synthesized by the method of coordinated atom substitution. The deformational and mechanical properties of the investigated materials are described in detail. The methodology of the NI is described, and both advantages and disadvantages of the NI method were analyzed. The description of the apparatus to conduct the experiments on NI was given. The basic provisions of a new model for describing the deformation properties of a nanoscale rigid two-layer structure on a porous elastic base were proposed. The original method of visualization of residual (after mechanical interaction) deformation in transparent and translucent materials was described. Experimentally determined values of elastic moduli and hardness of SiC nanoscale layers on Si formed by the method of coordinated substitution on three main crystal planes of Si, namely (100), (110) and (111), and elastic moduli and characteristics (elastic modulus, hardness, strength) of surface layers of semiconductor heterostructures AlN/SiC/Si, AlGaN/SiC/Si, AlGaN/AlN/SiC/Si, GaN/SiC/Si and GaN/AlN/SiC/Si grown on SiC/Si hybrid substrates. The unique mechanical properties of a new material β-Ga2O3 formed on SiC layers grown on Si surfaces of orientations (100), (110) and (111) were described.

Hierarchically Structured Ceramic Coatings Based on Zirconia and Magnesium Oxide with High Toughness

AbstractA major challenge in the application of ceramic materials is a trade‐off between strength and toughness. In this work, hierarchically structured ceramic coatings (HSCCs) are fabricated to address this challenge. HSCCs feature a dual‐layer micron‐scale structure built on a “brick‐mortar” nanoscale structure, which is achieved by changing the crystalline and amorphous phase ratio during plasma electrolytic oxidation (PEO). It is found that HSCCs with homogeneous interfaces exhibit high thermal stability up to 700 °C and a 65% improvement in shear strain resistance compared to conventional crystalline coatings (CCCs). This improvement is attributed to the stabilizing effect of atoms on the boundaries of the enhancement phase and the facilitating effect on the deformation of the compliant phase. The hierarchical structure effectively leverages the plasticity of the compliant phase and the strength of the enhancement phase facilitated by the homogeneous interface. This work proposes a feasible approach for improving the toughness of ceramic functional composites and mitigating their susceptibility to brittle fracture.

Research Trends in the Development of Block Copolymer-Based Biosensing Platforms.

Biosensing technology, which aims to measure and control the signals of biological substances, has recently been developed rapidly due to increasing concerns about health and the environment. Top-down technologies have been used mainly with a focus on reducing the size of biomaterials to the nano-level. However, bottom-up technologies such as self-assembly can provide more opportunities to molecular-level arrangements such as directionality and the shape of biomaterials. In particular, block copolymers (BCPs) and their self-assembly have been significantly explored as an effective means of bottom-up technologies to achieve recent advances in molecular-level fine control and imaging technology. BCPs have been widely used in various biosensing research fields because they can artificially control highly complex nano-scale structures in a directionally controlled manner, and future application research based on interactions with biomolecules according to the development and synthesis of new BCP structures is greatly anticipated. Here, we comprehensively discuss the basic principles of BCPs technology, the current status of their applications in biosensing technology, and their limitations and future prospects. Rather than discussing a specific field in depth, this study comprehensively covers the overall content of BCPs as a biosensing platform, and through this, we hope to increase researchers' understanding of adjacent research fields and provide research inspiration, thereby bringing about great advances in the relevant research fields.

Ultra-Low Threshold Resonance Switching by Terahertz Field Enhancement-Induced Nanobridge.

Ongoing efforts spanning decades aim to enhance the efficiency of optical devices, highlighting the need for a pioneering approach in the development of next-generation components over a broad range of electromagnetic wave spectra. The nonlinear transport of photoexcited carriers in semiconductors at low photon energies is crucial to advancements in semiconductor technology, communication, sensing, and various other fields. In this study, ultra-low threshold resonance mode switching by strong nonlinear carrier transport beyond the semi-classical Boltzmann transport regime using terahertz (THz) electromagnetic waves are demonstrated, whose energy is thousands of times smaller than the bandgap. This is achieved by employing elaborately fabricated 3D tip structures at the nanoscale, and nonlinear effects are directly observed with the THz resonance mode switching. The nanotip structure intensively localizes the THz field and amplifies it by more than ten thousand times, leading to the first observation of carrier multiplication phenomena in these low-intensity THz fields. This experimental findings, confirmed by concrete calculations, shed light on the newly discovered nonlinear behavior of THz fields and their strong interactions with nanoscale structures, with potential implications and insights for advanced THz technologies beyond the quantum regime.

Polydopamine-Modified Polycaprolactone Scaffolds Loading Metal Nanoparticles for Bone Tissue Engineering.

Recent advancements in materials synthesis and processing technology, coupled with a deeper understanding of bone nanoscale structure and biology, have provided new avenues for designing bioactive materials in bone tissue regenerative medicine. This Review focuses on the design and application of polydopamine-modified polycaprolactone scaffolds loading metal nanoparticles for bone tissue engineering. We explore their antibacterial properties and their ability to guide cell behavior. Specifically, we discuss the synthesis techniques, protein deposition, morphology variations, and interactions with the extracellular matrix of these scaffolds and biocompatibility and efficacy in promoting bone tissue regeneration in vitro and in vivo. Challenges and unmet needs are reviewed in the development of polymer- and metal-based materials for bone tissue engineering.

Structural Color of Partially Deacetylated Chitin Nanowhisker Film Inspired by Jewel Beetle.

Nanochitin was developed to effectively utilize crab shells, a food waste product, and there is ongoing research into its applications. Short nanowhiskers were produced by sonicating partially deacetylated nanochitin in water, resulting in a significant decrease in viscosity due to reduced entanglement of the nanowhiskers. These nanowhiskers self-assembled into a multilayered film through an evaporation technique. The macro- and nanoscale structures within the film manipulate light, producing vibrant and durable structural colors. The dried cast film exhibited green and purple stripes extending from the center to the edge formed by interference effects from the multilayer structure and thickness variations. Preserving structural colors requires maintaining a low ionic strength in the dispersion, as a higher ionic strength reduces electrostatic repulsion between nanofibers, increasing viscosity and potentially leading to the fading of color. This material's sensitivity to environmental changes, combined with chitin's biocompatibility, makes it well-suited for food sensors, wherein it can visually indicate freshness or spoilage. Furthermore, chitin's stable and non-toxic properties offer a sustainable alternative to traditional dyes in cosmetics, delivering vivid and long-lasting color.

Analyzing Extracellular Vesicle-associated DNA Using Transmission Electron Microscopy at the Single EV-level.

Extracellular vesicles (EVs) play an important role in cell-cell communication, carrying bioactive molecules including DNA. EV-associated DNA (EV-DNA) has created enormous interest in the field of biomarkers, particularly related to liquid biopsy. However, its analysis is challenging due to the nanoscale structure of EVs, the low abundance of EV-DNA, and surrounding biogenetic debate. Therefore, novel protocols to enhance the accurate detection of EV-DNA are essential to study its role in normal physiology and disease states. Here, we provide two protocols for confirming the presence of EV-DNA from biological samples. In the first protocol, ultrathin sectioning of EVs is combined with immunogold labeling to detect the presence of double-stranded (ds) DNA within the EV lumen using transmission electron microscopy (TEM). In the second protocol, whole-mount EV immunogold labeling allows detailed morphological analysis of EVs and their surface-associated DNA. Using TEM imaging, we have demonstrated that cancer-cell-derived individual EVs exhibit simultaneous positivity for dsDNA and the EV surface protein tetraspanin 9. We believe that this method can be used to label any proteins of interest inside as well as on the surface of EVs. This can aid in the characterization of single EVs and in the identification and verification of EV-associated biomarkers. © 2024 The Author(s). Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: EV isolation from cell-culture-conditioned medium, EV embedding, ultrathin sectioning, labeling, and imaging Basic Protocol 2: Whole-mount immunolabeling of EV-DNA.

Manipulation of ionic transport behavior in smart nanochannels by diffuse bipolar soft layer

Soft bipolar nanochannels provide distinct and valuable understanding of the intricate relationship among shape, charge distribution, concentration, and flow dynamics. This study investigates the intriguing realm of nanoscale structures, where two distinct configurations of soft layers with varying charges provide an intricate but appealing setting for the movement and management of ions, as well as the regulation and control of ionic species in nanochannels with five various geometries. It generates cylindrical, trumpet, dumbbell, hourglass, and conical forms. The nanochannels are coated with a diffuse polyelectrolyte layer, and the charge density distribution in the soft layer is described using the soft step distribution function. To enhance accuracy, the impact of ionic partitioning is taken into account. To investigate the effect of soft layer polarity, two types were considered: Type I and Type II. In Type I, the negative pole is at the start, while in Type II, the positive pole is at the start. Thus, Type I features a bipolar soft layer arrangement of negative–positive (NP), whereas Type II has a positive–negative (PN) configuration. The research was conducted under stationary conditions using the finite element method, Poisson–Nernst–Planck, and Navier–Stokes equations. By manipulating variables such as the arrangement order, charge density of the soft layer, and bulk concentration, a numerical analysis was performed to investigate the impact of these variables on current–voltage parameters. The results demonstrate the soft layer with a positive charge serves as a more effective receiver layer for generating greater rectification. For instance, the dumbbell-shaped nanochannel exhibits a rectification of 2046 at a concentration of 1 mM and the lowest charge density in the soft layer. From an alternative perspective, the conductivity in bipolar nanochannels is significantly influenced by the bulk concentration. The study's findings on the fundamental principles of soft bipolar nanochannels have profound implications for the diverse applications of nanochannels. The capacity to regulate and manipulate ion transport through these nanochannels can result in enhanced efficiency, selectivity, and performance in various processes.

Vortex light field microscopy: 3D spectral single-molecule imaging with a twist

3D single-molecule imaging reveals nanoscale structures in cell volumes but is limited by the need for spectrally distinct fluorophores. We address this limitation with vortex light field microscopy (VLFM), a 3D spectral single-molecule localization technique with 25 nm spatial and 3 nm spectral precision over a 4 µm depth of field. By modifying our previous single-molecule light field microscope with an azimuthally oriented prism array, we generated spectral disparity orthogonal to axial disparity, enabling simultaneous spatial and spectral localization on a single detector. We demonstrate VLFM with four-color 3D single-particle tracking and two-color 3D dSTORM imaging in fixed cells, successfully identifying dyes with spectral peaks just 15 nm apart. This shows VLFM’s potential for enhancing spatial biology workflows requiring highly multiplexed imaging.

Highly Transparent and Superhydrophobic SiO2 Coating with Nanoscale Structures by One-Step Spraying Technology for Applications as Self-cleaning Coatings

Highly Transparent and Superhydrophobic SiO₂ Coating with Nanoscale Structures by One-Step Spraying Technology for Applications as Self-cleaning Coatings

Boosting Low-E electro-strain via high-electronegativity B-site substitution in lead-free K0.5Na0.5NbO3-based ceramics

Lead-free piezoelectric actuators emerge as promising substitutes for their lead-containing counterparts to address environmental concerns. However, they often confront a trade-off between low driving electric fields and high electro-strain. Herein, a novel strategy to boost electro-strain under low electric fields is proposed by doping high-electronegativity B-site atoms into perovskite potassium sodium niobate-based ceramics. Our findings reveal that high-electronegativity B-site atoms elevate the covalency of B-O bonding, softening the short-range repulsion and introducing local multiphase coexistence. This leads to more nanoscale domain structures and lower coercive field, thereby enabling large strains to be produced at lower electric fields. Notably, a substantial 0.2 % bipolar electro-strain and 0.1 % unipolar electro-strain under 10 kV cm-1 is achieved in Sr, Sb co-doped potassium sodium niobate ceramics, with a broad working frequency and temperature range, as well as excellent fatigue resistance. This study unveils innovative insights into designing lead-free piezoelectric ceramics with remarkable electro-strain performance and low driving electric field, promising a significant advancement in lead-free piezoelectric materials science and piezoelectric actuators.

Facile fabrication of hemicrystalline bio-based polycarbonate with superhydrophobic and high transmittance

Developing materials that combine superhydrophobic properties with high optical transmittance poses a significant challenge. In this study, hydroxyl-terminated polydimethylsiloxane (HT-PDMS) and isosorbide (ISB) were polymerized in a single step to create a covalently bonded optical polycarbonate material. By inducing the formation of micro-papillary and lotus-shaped nanoscale structures via a solvent-triggered process, we significantly enhanced the “air cushion” effect, achieving a structure scale of approximately 5–7 μm. This resulted in a water contact angle of 157° while maintaining over 90 % optical transmittance. The structures were uniformly distributed throughout the polymer matrix, leading to a 500 % increase in tensile strength at break compared to pure isosorbide polycarbonate, with a maximum strength exceeding 50 MPa. These multifunctional materials show great promise for applications in smart windows, solar panels, camera lenses, and other optoelectronic devices.

Management of Plant Diseases with Green Synthesized Nanoparticles Using Plant Extracts

Nanotechnology is a rapidly advancing field that has effectively tackled various issues across multiple industries, including agriculture. Nanoparticles (NPs) can typically be synthesized using two different techniques: top-down approach and bottom-up approach. In top-down approach, NPs are generated by reducing the size of a larger material, resulting in agglomerates with nano sized particles. Bottom-up approach involves building nanoscale structures from atomic and molecular components. In agriculture, nanotechnology plays a role in the production of nanoscale fertilizers, pesticides, and herbicides. Nanoparticles are used in plant disease management as well. The green synthesis of nanoparticles is often referred to as biosynthesis. It uses a range of biological sources like microorganisms or their derivatives as well as plant extracts, instead of synthetic chemicals, with minimal impact on human health and the environment. Green-synthesized nanoparticles (GSNPs) are known for their ease of production and cost-effectiveness. They offer several advantages, including their ability to induce systemic resistance to diseases and exhibit fungicidal and bactericidal properties.

Sputtering of (111) highly-oriented nanotwinned Ag on polycrystalline Si3N4 substrates for high-power electronic packaging

Nanotwinned silver (NT-Ag) exhibits excellent mechanical and electrical properties, attributed to its high-density and (111) highly-oriented twinning structure in nanoscale. Therefore, it has recently drawn much attention in the field of electronic packaging, where it can be utilized as interconnection or metallization materials. However, it has been a critical challenge to fabricate the high-density and highly-oriented NT-Ag onto polycrystalline ceramic substrates, whose crystal structure does not support the epitaxial growth of NT-Ag films. In the current work, a high-density and highly-oriented NT-Ag film has been fabricated onto a polycrystalline ceramic substrate, i.e., NT-Ag on silicon nitride (NT-Ag@Si3N4), using the magnetron sputtering method. As results, a close-packed arrangement of high-density NT-Ag has been observed within columnar grains aligned along its growth direction, whereas the nanoindentation hardness of the NT-Ag film reached 1.82 GPa, with an electrical resistivity of 2.06 μΩ‧cm. Moreover, this study has discussed and explained the growth kinetics and mechanism of NT-Ag films, by controlling magnetron sputtering process parameters, such as sputtering power and argon flow rate. Additionally, the differences in the growth mechanism of NT-Ag on (100) Si and polycrystalline Si3N4 have also been investigated. With its superior material properties, NT-Ag@Si3N4 holds great promise in the applications of advanced packaging technology for high-power electronics.