Three-dimensional Nanostructures Research Articles

Fabrication of SERS composite substrates using Ag nanotriangles-modified SiO2 photonic crystal and the application of malachite green detection

A novel surface-enhanced Raman scattering (SERS) composite substrates on the basis of Ag triangular nanoplates(Ag TNPs)-modified SiO2 photonic crystals (PC) is fabricated and applied to the SERS detection of malachite green (MG). It consists of uniformly arranged Ag TNP@SiO2, a new PC. Notably, Ag TNP are uniformly aligned on the SiO2 surface, forming a three-dimensional high-density hotspot nanostructure. With the tip “hot spots” of Ag TNPs, Bragg diffraction of SiO2 and coupling enhancement between Ag TNPs and SiO2, the SERS enhancement of this composite substrates was multiplied. The effect on the SERS of Ag TNP@SiO2 composite substrate was systematically optimized by tuning Ag TNP size, size of SiO2 microspheres, coverage of Ag TNPs on SiO2 and fabrication method of Ag TNPs and PC. Moreover, the uniform of SERS composite substrates and Raman signal was dramatically increased by the method of vertical deposition. Eventually, the SERS composite substrates were employed in MG detection. Its broad detection range of 1 pM–1 μM and low limit of detection (LOD) of 0.49 pM indicated acceptable sensitivity and repeatability. This work illustrates the promising applicability in food safety analysis based on SERS composite substrates composed by Ag TNP@SiO2 with numerous SERS enhancements and excellent stability.

Fabrication of Rhenium Disulfide/Mesoporous Silica Core-Shell Nanoparticles for a pH-Responsive Drug Release and Combined Chemo-Photothermal Therapy.

A stimuli-responsive drug delivery nanocarrier with a core-shell structure combining photothermal therapy and chemotherapy for killing cancer cells was constructed in this study. The multifunctional nanocarrier ReS2@mSiO2-RhB entails an ReS2 hierarchical nanosphere coated with a fluorescent mesoporous silica shell. The three-dimensional hierarchical ReS2 nanostructure is capable of effectively absorbing near-infrared (NIR) light and converting it into heat. These ReS2 nanospheres were generated by a hydrothermal synthesis process leading to the self-assembly of few-layered ReS2 nanosheets. The mesoporous silica shell was further coated on the surface of the ReS2 nanospheres through a surfactant-templating sol-gel approach to provide accessible mesopores for drug uploading. A fluorescent dye (Rhodamine B) was covalently attached to silica precursors and incorporated during synthesis in the mesoporous silica walls toward conferring imaging capability to the nanocarrier. Doxorubicin (DOX), a known cancer drug, was used in a proof-of-concept study to assess the material's ability to function as a drug delivery carrier. While the silica pores are not capped, the drug molecule loading and release take advantage of the pH-governed electrostatic interactions between the drug and silica wall. The ReS2@mSiO2-RhB enabled a drug loading content as high as 19.83 mg/g doxorubicin. The ReS2@mSiO2-RhB-DOX nanocarrier's cumulative drug release rate at pH values that simulate physiological conditions showed significant pH responsiveness, reaching 59.8% at pH 6.8 and 98.5% and pH 5.5. The in vitro testing using HeLa cervical cancer cells proved that ReS2@mSiO2-RhB-DOX has a strong cancer eradication ability upon irradiation with an NIR laser owing to the combined drug delivery and photothermal effect. The results highlight the potential of ReS2@mSiO2-RhB nanoparticles for combined cancer therapy in the future.

Synergistic enhancement of wearable biosensor through Pt single-atom catalyst for sweat analysis

Real-time monitoring of biological markers in sweat is a valuable tool for health assessment. In this study, we have developed an innovative wearable biosensor for precise analysis of glucose in sweat during physical activities. The sensor is based on a single-atom catalyst of platinum (Pt) uniformly dispersed on tricobalt tetroxide (Co3O4) nanorods and reduced graphene oxide (rGO), featuring a unique three-dimensional nanostructure and excellent glucose electrocatalytic performance with a wide detection range of 1–800 μM. Additionally, density functional theory calculations have revealed the synergetic role of Pt active sites in the Pt single-atom catalyst (Co3O4/rGO/Pt) in glucose adsorption and electron transfer, thereby enhancing sensor performance. To enable application in wearable devices, we designed an S-shaped microfluidic chip and a point-of-care testing (POCT) device, both of which were validated for effectiveness through actual use by volunteers. This research provides valuable insights and innovative approaches for analyzing sweat glucose using wearable devices, contributing to the advancement of personalized healthcare.

A Rapid Self-Assembling Peptide Hydrogel for Delivery of TFF3 to Promote Gastric Mucosal Injury Repair.

Self-assembled peptide-based nanobiomaterials exhibit promising prospects for drug delivery applications owing to their commendable biocompatibility and biodegradability, facile tissue uptake and utilization, and minimal or negligible unexpected toxicity. TFF3 is an active peptide autonomously secreted by gastric mucosal cells, possessing multiple biological functions. It acts on the surface of the gastric mucosa, facilitating the repair process of gastric mucosal damage. However, when used as a drug, TFF3 faces significant challenges, including short retention time in the gastric mucosal cavity and deactivation due to degradation by stomach acid. In response to this challenge, we developed a self-assembled short peptide hydrogel, Rqdl10, designed as a delivery vehicle for TFF3. Our investigation encompasses an assessment of its properties, biocompatibility, controlled release of TFF3, and the mechanism underlying the promotion of gastric mucosal injury repair. Congo red/aniline blue staining revealed that Rqdl10 promptly self-assembled in PBS, forming hydrogels. Circular dichroism spectra indicated the presence of a stable β-sheet secondary structure in the Rqdl10 hydrogel. Cryo-scanning electron microscopy and atomic force microscopy observations demonstrated that the Rqdl10 formed vesicle-like structures in the PBS, which were interconnected to construct a three-dimensional nanostructure. Moreover, the Rqdl10 hydrogel exhibited outstanding biocompatibility and could sustainably and slowly release TFF3. The utilization of the Rqdl10 hydrogel as a carrier for TFF3 substantially augmented its proliferative and migratory capabilities, while concurrently bolstering its anti-inflammatory and anti-apoptotic attributes following gastric mucosal injury. Our findings underscore the immense potential of the self-assembled peptide hydrogel Rqdl10 for biomedical applications, promising significant contributions to healthcare science.

Low-Temperature Deposition of Diamond Films by MPCVD with Graphite Paste Additive

Modern integrated circuits (ICs) take advantage of three-dimensional (3D) nanostructures in devices and interconnects to achieve high-speed and ultra-low-power performance. The choice of electrical insulation materials with excellent dielectric strength, electrical resistivity, strong mechanical strength, and high thermal conductivity becomes critical. Diamond possesses these properties and is recently recognized as a promising dielectric material for the fabrication of advanced ICs, which are sensitive to detrimental high-temperature processes. Therefore, a high-rate low-temperature deposition technique for large-grain, high-quality diamond films of the thickness of a few tens to a few hundred nanometers is desirable. The diamond growth rate by microwave plasma chemical vapor deposition (MPCVD) decreases rapidly with lowering substrate temperature. In addition, the thermal conductivity of non-diamond carbon is much lower than that of diamond. Furthermore, a small-grain diamond film suffers from poor thermal conductivity due to frequent phonon scattering at grain boundaries. This paper reports a novel MPCVD process aiming at high growth rate, large grain size, and high sp3/sp2 ratio for diamond films deposited on silicon. Graphite paste containing nanoscale graphite and oxy-hydrocarbon binder and solvent vaporizes and mixes with gas feeds of hydrogen, methane, and carbon dioxide to form plasma. Rapid diamond growth of diamond seeds at 450 °C by the plasma results in large-grained diamond films on silicon at a high deposition rate of 200 nm/h.

Facile synthesis of Au–TiO2/Bacterial cellulose aerogel nanocomposites with enhanced photocatalytic degradation of methylene blue under UV irradiation

The Au–TiO2/Bacterial cellulose aerogel nanocomposites (Au–TiO2/BC NCs) with remarkable photocatalytic properties and designed to solve agglomeration and reusability challenges in wastewater treatment have been successfully synthesized. The integration of gold nanoparticles (Au NPs) with TiO2, in conjunction with bacterial cellulose (BC) serving as a three-dimensional nanostructure, resulted in the formation of Au–TiO2/BC NCs through mechanical compositing, a confirmation obtained through various characterization techniques including XRD, SEM, SEM-EDS, TEM, TEM-EDS, BET, XPS, FT-IR, Spectrofluorometer, Raman, and UV–vis spectroscopy. The combination of Au–TiO2 nanoparticles with BC showcased homogeneous coverage over BC nanostructures, attributed to BC's unique properties, particularly its surface hydroxyl groups that prevent TiO2 agglomeration, along with uniform distribution of Au nanoparticles on TiO2 layers. Photocatalytic activity, assessed through methylene blue (MB) degradation under both UV and direct sunlight irradiation, demonstrated significantly improved efficiency with AuNPs, achieving approximately 90% degradation in the Au–TiO2/BC NCs under UV irradiation. The synthesized NCs exhibited stability with a slight performance reduction after cyclic tests, indicating potential for wastewater treatment applications under diverse light conditions. The integration of Au NPs onto TiO2 surfaces amplified light-induced reactions, addressing critical challenges in environmental remediation, particularly in the degradation of persistent environmental pollutants. This study offers valuable insights, positioning Au–TiO2/BC NCs as promising candidates for sustainable environmental remediation, emphasizing reusability, enhanced photocatalytic performance, and a straightforward synthesis process under both UV and direct sunlight irradiation.

Large-scale SU-8 Micro-Pole-Arrays decorated with Hierarchical Metal-Dielectric-Metal nanostructures as sensitive 3D SERS substrates

Dielectric layer-mediated surface-enhanced Raman scattering (SERS) substrates are currently explored for ultrasensitive detection and expected to provide uniform SERS response by the virtue of three-dimensional micro-nanostructures, dielectric layer, and plasmonic metal nanostructures. For this purpose, the present work reports on the development of the metal-dielectric-metal (MDM) three-dimensional (3D) micro-pole-arrays structure based on SU-8 colloid lithography. By utilizing the large-scale periodic arrangement characteristics of SU-8 colloidal lithography, along with the hot spot effect created by the nano-gap between MDM, we successfully prepared an array of SERS substrates that exhibit both periodicity and multi-dimensional plasmonic coupling effect. Compared to a single metal nanoparticle substrate, the SERS activity of the substrate is significantly enhanced, and the substrate has trace detection ability (LOD of detection of 10−12 mol/L for R6G). The enhancement factor (EF) is 5.72 × 107. Periodicity ensures that the prepared substrate has good reproducibility (RSD < 8 %) and stability. Furthermore, the substrate modified with HS-β-CD demonstrated potential for rapid trace SERS detection of polychlorinated biphenyls (PCB-77) (LOD of 10−8 mol/L for PCB-77). The results indicate that the proposed substrate has the potential for application in the preparation of SERS sensors with high sensitivity and uniformity.

Three-dimensional nanostructures of crosslinked aramid nanofibers with exceptional mechanical and thermal insulation characteristics

Despite the remarkable attributes of aramid nanofibers, which include a high aspect ratio, elevated strength and modulus, as well as exceptional chemical and thermal stabilities, their utilization in three-dimensional porous nanostructures remains constrained due to the inherent challenge of agglomeration between adjacent fibers. This study presents a novel approach involving citric acid-assisted crosslinking to mitigate aramid nanofiber agglomeration. By facilitating the formation of covalent bonds between aramid nanofibers and citric acid, this method leads to the development of a three-dimensional open-porous structure. The chemically crosslinked aramid nanofibers/citric acid composite demonstrated notable enhancements in physical, mechanical, and thermal insulation properties, including an ultra-low density of 8.7 mg cm−3, exceptional compressive and tensile strengths at 3.04 MPa and 287 kPa, respectively, and a low thermal conductivity of 40 mW m−1 K−1. These advancements can be attributed to the preservation of the porous structure achieved through established covalent bonds. These findings carry significant implications for unlocking the potential of aramid nanofibers, particularly in advancing fields like thermal maintenance, insulation, construction of ultra-light structures, and the mitigation of vibration or impact energy in demanding environments.

Achieving high selectivity and activity of CO2 electroreduction to formate by in-situ synthesis of single atom Pb doped Cu catalysts

Exploring highly selective and stable electrocatalysts is of great significance for the electrochemical conversion of CO2 into fuel. Herein, a three-dimensional (3D) nanostructure catalyst was developed by doping Pb single-atom (PbSA) in-situ on carbon paper (PbSA100-Cu/CP) through a low-energy and economical method. The designed catalyst exhibited abundant active sites and was beneficial to CO2 adsorption, activation, and subsequent conversion to fuel. Interestingly, PbSA100-Cu/CP showed a prominent Faraday efficiency (FE) of 97 % at –0.9 V versus reversible hydrogen electrode (vs. RHE) and a high partial current density of 27.9 mA·cm−2 for formate. Also, the catalyst remained significantly stable for 60 h during the durability test. The reaction mechanism was investigated by density functional theory (DFT), demonstrating that the doping PbSA induced the electrons redistribution, promoted the formate generation, reduced the rate-determining step (RDS) energy barrier, and inhibited the hydrogen evolution reaction. The study aims to provide a new strategy for developing of single-atom catalysts with high selectivity and stability, which will help reduce environmental pressure and alleviate energy problems.

Accelerating water dissociation at hierarchical nanostructured electrocatalyst for efficient hydrogen evolution

The sluggish kinetics of the water electrolysis reaction is a key issue for hydrogen production, so the rational design of a high-efficiency hydrogen evolution reaction (HER) electrocatalyst with various structures has attracted extensive attention. Herein, a coaxial hierarchical three-dimensional (3D) nanostructure, Pt@Mo–S–Ni-CNTs, was prepared. In this nanostructure, carbon nanotubes (CNTs) as the core, Mo–S–Ni ultrathin nanosheets as shells, and ultrasmall metal nanoparticles (NPs) were grown uniformly on the surface of Mo–S–Ni nanosheets (NSs). At a current density of 10 mA m−2, the catalyst under investigation has remarkable hydrogen evolution reaction (HER) activity under acidic conditions. The overpotential (η10) is measured to be 61.2 mV, while the Tafel slope is determined to be 40.2 mV dec−1. Meanwhile, in an alkaline medium, η10 is 80.5 mV and the Tafel slope is 52.3 mV dec−1. It also shows great mass activities of 1.32 A mg−1 and 1.86 A mg−1, which are higher than those of commercial Pt/C HER catalysts. Impressively, the excellent HER activity and durability of Pt@Mo–S–Ni-CNTs are mainly attributed to the close binding effects among Pt, MoS2, and NiS. Theoretical simulations show that the MoS2/NiS interfaces facilitate H2O dissociation and that Platinum (Pt) enhances the absorption of hydrogen atoms (H) and increases the charge transfer kinetics of the Mo–S–Ni, thus significantly improving the HER activity. This work highlights the importance of engineering interface nanosheets based on transition-metal dichalcogenides for enhanced HER performance.

Crystal plasticity simulations reveal cooperative plasticity mechanisms leading to enhanced strength and toughness in gradient nanostructured metals

Heterogeneous deformation is thought to provide the strengthening in gradient nanostructured metals, but the underlying plasticity mechanisms and optimal gradient structures for attaining improved mechanical performance remain elusive. Through crystal plasticity simulations of three-dimensional heterogeneous nanostructures, we reveal the heterogeneous-deformation-induced plasticity mechanisms which evoke increased flow strength and strain hardening. We have developed a synthetic microstructure generation algorithm which replicates both the microstructural features and external geometry of experimentally characterized samples—providing a direct comparison between the mechanical response recorded in simulations and experiments. Aligning well with experiments, the simulations show synergistically enhanced mechanical properties. High strain hardening rates directly correlate to large stress gradients that emerge due to heterogeneous deformation. Samples with smooth grain size gradients exhibit the most extreme stress gradients and correspondingly higher strain hardening rates. Large increases in dislocation density—especially within larger grains—and high intra- and inter-granular crystal rotation are plasticity mechanisms common to samples which exhibit high mechanical performance. Although the nanostructural gradients have pronounced influence over the mechanical performance, samples with the same grain size and dislocation density gradients exhibit varied mechanical properties. We show that the distribution of initial grain orientations and the microstructural constraints placed on larger grains also influence the active plasticity mechanisms providing improved mechanical properties.

Direct-write 3D printing of plasmonic nanohelicoids by circularly polarized light

Chiral plasmonic surfaces with 3D "forests" from nanohelicoids should provide strong optical rotation due to alignment of helical axis with propagation vector of photons. However, such three-dimensional nanostructures also demand multi-step nanofabrication, which is incompatible with many substrates. Large-scale photonic patterns on polymeric and flexible substrates remain unattainable. Here, we demonstrate the substrate-tolerant direct-write printing and patterning of silver nanohelicoids with out-of-plane 3D orientation using circularly polarized light. Centimeter-scale chiral plasmonic surfaces can be produced within minutes using inexpensive medium-power lasers. The growth of nanohelicoids is driven by the symmetry-broken site-selective deposition and self-assembly of the silver nanoparticles (NPs). The ellipticity and wavelength of the incident photons control the local handedness and size of the printed nanohelicoids, which enables on-the-fly modulation of nanohelicoid chirality during direct writing and simple pathways to complex multifunctional metasurfaces. Processing simplicity, high polarization rotation, and fine spatial resolution of the light-driven printing of stand-up helicoids provide a rapid pathway to chiral plasmonic surfaces, accelerating the development of chiral photonics for health and information technologies.

Probing Temperature-Induced Plasmonic Nonlinearity: Unveiling Opto-Thermal Effects on Light Absorption and Near-Field Enhancement.

Precise measurement and control of local heating in plasmonic nanostructures are vital for diverse nanophotonic devices. Despite significant efforts, challenges in understanding temperature-induced plasmonic nonlinearity persist, particularly in light absorption and near-field enhancement due to the absence of suitable measurement techniques. This study presents an approach allowing simultaneous measurements of light absorption and near-field enhancement through angle-resolved near-field scanning optical microscopy with iterative opto-thermal analysis. We revealed gold thin films exhibit sublinear nonlinearity in near-field enhancement due to nonlinear opto-thermal effects, while light absorption shows both sublinear and superlinear behaviors at varying thicknesses. These observations align with predictions from a simple harmonic oscillation model, in which changes in damping parameters affect light absorption and field enhancement differently. The sensitivity of our method was experimentally examined by measuring the opto-thermal responses of three-dimensional nanostructure arrays. Our findings have direct implications for advancing plasmonic applications, including photocatalysis, photovoltaics, photothermal effects, and surface-enhanced Raman spectroscopy.

Understanding the Effect of Curvature on the Magnetization Reversal of Three-Dimensional Nanohelices.

Comprehending the interaction between geometry and magnetism in three-dimensional (3D) nanostructures is important to understand the fundamental physics of domain wall (DW) formation and pinning. Here, we use focused-electron-beam-induced deposition to fabricate magnetic nanohelices with increasing helical curvature with height. Using electron tomography and Lorentz transmission electron microscopy, we reconstruct the 3D structure and magnetization of the nanohelices. The surface curvature, helical curvature, and torsion of the nanohelices are then quantified from the tomographic reconstructions. Furthermore, by using the experimental 3D reconstructions as inputs for micromagnetic simulations, we can reveal the influence of surface and helical curvature on the magnetic reversal mechanism. Hence, we can directly correlate the magnetic behavior of a 3D nanohelix to its experimental structure. These results demonstrate how the control of geometry in nanohelices can be utilized in the stabilization of DWs and control of the response of the nanostructure to applied magnetic fields.

The electrochemical performances of high surface area mesocellular anatase TiO2 foam anode for lithium–ion battery

Porous anatase TiO2 with mesocellular foam structure (MCF−TiO2) was facilely prepared through hard-templating using mesocellular foam carbon (MCF−C), which had been prepared through hard-templating using mesocellular silica foam (MCF). During the dual hard-templating processes, the MCF−TiO2 well preserved the original three-dimensional (3D) mesocellular nanostructure of MCF. The wall of MCF−TiO2 was composed of very tiny anatase TiO2 nanocrystals (NCs). The TiO2 NCs were of less than 20 nm dimension. The surface area of MCF−TiO2 was 144 m2 g−1, and the MCF−TiO2 also contained large void spaces. The high surface area 3D nanostructured anatase MCF−TiO2 with large void spaces was ideal for Li+ transport and charge transfer reactions when MCF−TiO2 was applied to the anode material of the lithium–ion battery (LIB). Galvanostatic charge–discharge measurement and cyclic voltammetry confirmed that the MCF−TiO2 was an efficient anode material. The specific capacity after 50 cycles at a current rate of 0.1C reached 187 mAh g−1; it also showed stable recycling performances due to the robust high surface area 3D nanostructure.

3D Noble-Metal Nanostructures Approaching Atomic Efficiency and Atomic Density Limits.

Noble metals have been widely used in catalysis, however, the scarcity and high cost of noble metal motivate researchers to balance the atomic efficiency and atomic density, which is formidably challenging. This article proposes a robust strategy for fabricating 3D amorphous noble metal-based oxides with simultaneous enhancement on atomic efficiency and density with the assistance of atomic channels, where the atomic utilization increases from 18.2% to 59.4%. The unique properties of amorphous bimetallic oxides and formation of atomic channels have been evidenced by detailed experimental characterizations and theoretical simulations. Moreover, the universality of the current strategy is validated by other binary oxides. When Cu2IrOx with atomic channels (Cu2IrOx-AE) is used as catalyst for oxygen evolution reaction (OER), the mass activity and turnover frequency value of Cu2IrOx-AE are 1-2 orders of magnitude higher than CuO/IrO2 and Cu2IrOx without atomic channels, largely outperforming the reported OER catalysts. Theoretical calculations reveal that the formation of atomic channels leads to various Ir sites, on which the proton of adsorbed *OH can transfer to adjacent O atoms of [IrO6]. This work may attract immediate interest of researchers in material science, chemistry, catalysis, and beyond.

Enhanced interfacial property and thermal conductivity of pitch-based carbon fiber/epoxy composites via three-layer assembly of PDI/GN/PDI interphase

Π-conjugate perylene diimide (PDI)/graphene (GN)/PDI interphase was designed and constructed on pitch-based carbon fiber (PCF) surface by multi-layer assembly, and the interfacial and thermal conductive performances of PCF/Epoxy (EP) composites with PDI, PDI/GN and PDI/GN/PDI interphase were investigated. Flat nanoscale structures with fragmented and wrinkled GN, PDI nanowires were respectively observed on PCF-GN, PCF-PDI/GN and PCF-PDI surface, while three-dimensional oblique cicada-wing nanostructure of three-layer interphase was constructed on PCF-PDI/GN/PDI surface due to the re-assembly of PDI under confinement constraint of GN substrate. Interlayer shear strength and transverse fiber bundle tensile strength of PCF-PDI/GN/PDI/EP composite were 28.4 %, 9.36 %, 12.0 % and 246 %, 85.8 %, 116 % higher than those of PCF-GN/EP, PCF-PDI/GN/EP and PCF-PDI/EP composites, which were attributed to the improvement of interface adhesion and the effectively buffer stress transfer between carbon fiber and resin matrix by introducing three-layer PDI/GN/PDI interphase. Additionally, PCF-PDI/GN/PDI/EP composites showed the highest heat conduction and thermal conductivity, ascribing to the construction of extra conductive paths and the weakening of phonons scattering from three-dimensional (3D) structure of PDI/GN/PDI interphase, which realized the formation of structure-function integration interphase of pitch-based carbon fiber composites.

3D-Nanostructured microfluidic device arranged in a herringbone pattern for the highly effective capture of HER2-Positive cancer-derived exosomes in urine

Exosomes in body fluids are important in liquid biopsy as they reflect the information of their originating cells. Thus, exosome analysis can provide valuable insights into diseases such as cancer. However, the low concentration of exosomes in body fluids is accompanied by background noise, making exosome analysis challenging. Here, a microfluidic chip in which three-dimensional nanostructures were arranged in a herringbone pattern (nanochip) that could efficiently capture specific exosomes was developed. Nanostructures were prepared by stacking silica nanoparticles to enhance the contact and interaction between the exosomes and structures, which were then arranged in a herringbone pattern to improve mass transfer through micromixing. To analyze exosomes derived from human epidermal growth factor receptor 2 (HER2, an important marker for cancer progression and patient survival)-positive cancer, anti-HER2 antibody was introduced into the nanostructures in the nanochip and approximately 97.7% of exosome capture efficiency was confirmed. The nanochip performed better than chips with a solid herringbone structure or without a structure (solid and flat chips). The feasibility of capturing multiple exosomes was demonstrated using both in vitro and in vivo samples by employing a dual nanochip configuration in which nanochips with different antibodies were interconnected in a series. This nanochip can effectively capture HER2-positive exosomes and has potential for multiple exosome isolations. Additionally, this chip can capture and detect various disease-related exosomes because various antibodies can be applied; this nanochip will be useful for exosome-based disease diagnosis and monitoring in liquid biopsies.

Realization of all two-dimensional Bravais lattices with metasurface-based interference lithography

Abstract Proximity-field nanopatterning (PnP) have been used recently as a rapid, cost-effective, and large-scale fabrication method utilizing volumetric interference patterns generated by conformal phase masks. Despite the effectiveness of PnP processes, their design diversity has not been thoroughly explored. Here, we demonstrate that the possibility of generating any two-dimensional lattice with diverse motifs. By controlling the amplitude, phase, and polarization of each diffraction beam, we can implement all two-dimensional Bravais lattices in three-dimensional space. The results may provide diverse applications that require three-dimensional nanostructures from optical materials and structural materials to energy storage or conversion materials.

Three-dimensional nanostructure analysis of non-stained Nafion in fuel-cell electrode by combined ADF-STEM tomography.

The polymer electrolyte fuel cell (PEFC) is one of the strongest candidates for a next-generation power source for vehicles which do not emit CO2 gas as exhaust gas. The key factor in PEFCs is the nano-scaled electrochemical reactions that take place on the catalyst material and an ionomer supported by a carbon support. However, because the nano-scaled morphological features of the key materials in the catalyst compound cannot be observed clearly by transmission electron microscopy, improvement of PEFC performance had been approached by an imaginal schematic diagram based on an electrochemical analysis. In this study, we revealed the nano-scaled morphological features of the PEFC electrode in three dimensions and performed a quantitative analysis of the nanostructure by the newly developed 'Combined ADF-STEM tomography technique'. This method combines information from plural annular darkfield detectors with different electron collection angles and can emphasize the difference of the electron scattering intensity between the ionomer and carbon in the cross-sectional image of the reconstructed three-dimensional (3D) data. Therefore, this segmentation method utilizing image contrast does not require a high electron beam current like that used in energy dispersive X-ray analysis, and thus is suitable for electron beam damage-sensitive materials. By eliminating the process of manually determining the thresholds for obtaining classified component data from grayscale data, the obtained 3D structures have sufficient accuracy to allow quantitative analysis and specify the nano-scaled structural parameters directly related to power generation characteristics.