Investigating chiral morphogenesis of gold using generative cellular automata.

Homochirality is an important feature in biological systems and occurs even in inorganic nanoparticles. However, the mechanism of chirality formation and the key steps during growth are not fully understood. Here we identify two distinguishable pathways from achiral to chiral morphologies in gold nanoparticles by training an artificial neural network of cellular automata according to experimental results. We find that the chirality is initially determined by the nature of the asymmetric growth along the boundaries of enantiomeric high-index planes. The deep learning-based interpretation of chiral morphogenesis provides a theoretical understanding but also allows us to predict an unprecedented crossover pathway and the resulting morphology.

Kink-Controlled Gold Nanoparticles for Electrochemical Glucose Oxidation.

Enzymes in nature efficiently catalyze chiral organic molecules by elaborately tuning the geometrical arrangement of atoms in the active site. However, enantioselective oxidation of organic molecules by heterogeneous electrocatalysts is challenging because of the difficulty in controlling the asymmetric structures of the active sites on the electrodes. Here, we show that the distribution of chiral kink atoms on high-index facets can be precisely manipulated even on single gold nanoparticles; and this enabled stereoselective oxidation of hydroxyl groups on various sugar molecules. We characterized the crystallographic orientation and the density of kink atoms and investigated their specific interactions with the glucose molecule due to the geometrical structure and surface electrostatic potential.

Tuning the CO2 Reduction Selectivity of an Immobilized Molecular Ag Complex beyond CO.

The electrochemical reduction of carbon dioxide (CO2) to produce fuels and chemicals has garnered significant attention. However, achieving control over the selectivity of the resulting products remains a challenging task, particularly within molecular systems. In this study, we employed a molecular silver complex immobilized on graphitized mesoporous carbon (GMC) as a catalyst for converting CO2 into CO, achieving an impressive selectivity of over 90% at -1.05 V vs RHE. Notably, the newly formed silver nanoparticles emerged as the active sites responsible for this high CO selectivity rather than the molecular system. Intriguingly, the introduction of copper ions into the restructured Ag-nanoparticle-decorated carbon altered the product selectivity. At -1.1 V vs RHE in 0.1 M KCl, we achieved a high C2 selectivity of 75%. Furthermore, not only the Ag-Cu bimetallic nanoparticle but also the small-sized Ag-Cu nanocluster decorated over GMC was proposed as active sites during catalytic reactions. Our straightforward approach offers valuable insights for fine-tuning the product selectivity of immobilized molecular systems, extending beyond C1 products.

Circular polarization sensitive opto-neuromorphic operation at plasmonic hot electron transistor using chiral gold nanoparticles.

Opto-neuromorphic operation is critical for biological system to recognize the visual objects and mimicking such operation is important for artificial prosthesis as well as machine vision system for industrial applications. To sophisticatedly mimic biological system, regulation of learning and memorizing efficiency is needed, however engineered synthetic platform has been lack of controllability, which makes huge gap between biological system and synthetic platform. Here we demonstrated controllable learning and memorizing opto-neuromorphic operation at plasmonic hot electron transistor. Especially, circularly polarized light (CPL) sensitive synaptic characteristics and learning experience capability are enabled by incorporating chiral plasmonic nanoparticle. Furthermore, gate voltage gives rise to controllable neuromorphic operation due to hot electron injection and trapping effect, resulting in high remaining synaptic weight of ∼70% at negative gate voltage under CPL excitation. We believe that this discovery makes significant leap toward on-demand in-sensor computing as well as toward bio-realistic device.

Visual Outcome and Fluid Changes Between Eyes With Polypoidal Choroidal Vasculopathy Receiving Biosimilar CKD-701 or Reference Ranibizumab Therapy: A Post Hoc Analysis of a Phase 3 Randomized Clinical Trial.

PURPOSE: To compare the visual outcome and fluid features of a proposed biosimilar, CKD-701, versus the reference ranibizumab in eyes with polypoidal choroidal vasculopathy (PCV). METHODS: This was a post hoc analysis of a phase 3 randomized clinical trial assessing the efficacy and safety of CKD-701 and ranibizumab. A total of 73 PCV eyes were assigned randomly to either CKD-701 (36 eyes) or ranibizumab (37 eyes). The mean changes in best-corrected visual acuity (BCVA), central retinal thickness (CRT), pigment epithelial detachment (PED) volume, and fluid features were compared. RESULTS: After three loading injections, the mean change in BCVA (letters) was +7.50 in the CKD-701 group and +6.32 in the ranibizumab group (p = .447). The changes in CRT and PED volume of the CKD-701 group (-107.25 ± 102.66 µm and -0.22 ± 0.46 mm3) were similar to those of the ranibizumab group (-96.78 ± 105.00 µm and -0.23 ± 0.54 mm3) (p = .668 and p = .943, respectively). Proportions of eyes with subretinal, intraretinal and sub-retinal pigment epithelium (RPE) fluids after three loading injections were not different between CKD-701 group (33.3%, 13.9% and 42.9%) and ranibizumab group (51.4%, 16.2% and 40.0%) (p = .071, p = 1.000 and p = .808). The visual and anatomical changes were similar between two groups at month 6 and 12 (all, p > .05). CONCLUSION: Biosimilar CKD-701 monotherapy resulted in comparable visual and anatomical changes to those achieved with reference ranibizumab in PCV eyes.

Photochemical tuning of dynamic defects for high-performance atomically dispersed catalysts.

Developing active and stable atomically dispersed catalysts is challenging because of weak non-specific interactions between catalytically active metal atoms and supports. Here we demonstrate a general method for synthesizing atomically dispersed catalysts via photochemical defect tuning for controlling oxygen-vacancy dynamics, which can induce specific metal-support interactions. The developed synthesis method offers metal-dynamically stabilized atomic catalysts, and it can be applied to reducible metal oxides, including TiO2, ZnO and CeO2, containing various catalytically active transition metals, including Pt, Ir and Cu. The optimized Pt-DSA/TiO2 shows unprecedentedly high photocatalytic hydrogen evolution activity, producing 164 mmol g-1 h-1 with a turnover frequency of 1.27 s-1. Furthermore, it generates 42.2 mmol gsub-1 of hydrogen via a non-recyclable-plastic-photoreforming process, achieving a total conversion of 98%; this offers a promising solution for mitigating plastic waste and simultaneously producing valuable energy sources.

Chiral plasmonic sensing: From the perspective of light-matter interaction.

Molecular chirality is represented as broken mirror symmetry in the structural orientation of constituent atoms and plays a pivotal role at every scale of nature. Since the discovery of the chiroptic property of chiral molecules, the characterization of molecular chirality is important in the fields of biology, physics, and chemistry. Over the centuries, the field of optical chiral sensing was based on chiral light-matter interactions between chiral molecules and polarized light. Starting from simple optics-based sensing, the utilization of plasmonic materials that could control local chiral light-matter interactions by squeezing light into molecules successfully facilitated chiral sensing into noninvasive, ultrasensitive, and accurate detection. In this Review, the importance of plasmonic materials and their engineering in chiral sensing are discussed based on the principle of chiral light-matter interactions and the theory of optical chirality and chiral perturbation; thus, this Review can serve as a milestone for the proper design and utilization of plasmonic nanostructures for improved chiral sensing.

Comparison of retinal thickness measurements among four different optical coherence tomography devices.

We sought to compare the retinal thickness measurements collected using different optical coherence tomography (OCT) devices. This prospective study included 21 healthy cases, and the retinal thickness was measured using the PLEX Elite (Carl Zeiss Meditec, Dublin, California, USA), DRI OCT-1 Atlantis (Topcon Corp, Tokyo, Japan), Cirrus 5000 HD-OCT (Carl Zeiss Meditec), and Spectralis OCT (Heidelberg Engineering, Heidelberg, Germany), respectively. The mean central retinal thickness (CRT) and mean retinal thickness of the Early Treatment of Diabetic Retinopathy Study (ETDRS) area were compared. The CRT varied significantly among the different OCT devices (P < 0.001). Post-hoc analysis revealed that the CRT measured using PLEX Elite (278.95 ± 20.04 µm) and Spectralis (271.86 ± 17.92 µm) were similar, and both were greater than the CRT measurements of DRI OCT-1 (239.57 ± 21.06 µm) and Cirrus (256.76 ± 17.82 µm). Additionally, the mean retinal thickness in each ETDRS area showed significant differences among the four devices (all P < 0.001). The mean retinal thickness measured varied according to the device used, and this needs to be considered when comparing retinal thickness measurements taken with different devices.

Promoting hydrophilic cupric oxide electrochemical carbon dioxide reduction to methanol via interfacial engineering modulation.

Copper-based catalysts have been extensively investigated in electrochemical carbon dioxide (CO2) reduction to promote carbon products generated by requiring multiple electron transfer. However, hydrophilic electrodes are unfavourable for CO2 mass transfer and preferentially hydrogen (H2) evolution in electrochemical CO2 reduction. In this paper, a hydrophilic cupric oxide (CuO) electrode with a grassy morphology was prepared. CuO-derived Cu was confirmed as the active site for electrochemical CO2 reduction through wettability modulation. To enhance the intrinsic catalytic activity, a metal-oxide heterogeneous interface was created by engineering modulation at the interface, involving the loading of palladium (Pd) on CuO (CuO/Pd). Both the electrochemically active area and the electron transfer rate were enhanced by Pd loading, and significantly the reduced work function further facilitated the electron transfer between the electrode surface and the electrolyte. Consequently, the CuO/Pd electrode exhibited excellent excellent performance in electrochemical CO2 reduction, achieving a 54 % Faraday efficiency at -0.65 V for methanol (CH3OH). The metal-oxide interfacial effect potentially improves the intrinsic catalytic activity of hydrophilic CuO electrodes in electrochemical CO2 reduction, providing a conducive pathway for optimizing hydrophilic oxide electrodes in this process.

Enhancement of second-harmonic generation in a 64° stacked WSe2/WS2heterobilayer with local strain.

Transition metal dichalcogenides (TMDs) are actively studied in various fields of optics and optoelectronics, including nonlinear optics of second-harmonic generation (SHG). By stacking two different TMD materials to form a heterobilyaer, unique optical properties emerge, with stronger SHG at a twist angle of 0° between TMDs and weaker SHG at a twist angle of 60°. In this work, we demonstrate the enhancement of SHG in a heterobilayer consisting of WSe2and WS2monolayers stacked at a twist angle of 64.1°, using a nanoparticle to induce local strain. The interatomic spacing of the heterobilayer is deformed by the nanoparticle, breaking the inversion symmetry, resulting in a substantial increase in the SHG of the heterobilayer at room temperature. The SHG increases depending on the polarization of the pump laser: 15-fold for linear polarization, 9-fold for right-circular polarization, and up to 100-fold for left-circular polarization. In addition, the SHG enhanced in the heterobilayer with local strain satisfies the same chiral selection rule as in the unstrained TMD region, demonstrating that the chiral selection rule of SHG is insensitive to local strain. Our findings will increase the applicability of TMD heterobilayers in nonlinear optoelectronics and valleytronics.

Selective Targeting of Nanobody-Modified Gold Nanoparticles to Distinct Cell Types.

Nanobody-modified gold nanoparticles were used to explore their ability to achieve selective targeting in vitro and in vivo to distinct cell type(s), based on the specificity of the nanobody that was installed. We developed conjugation methods that exploit click chemistry for octahedral ∼50 nm gold nanoparticles and chiral ∼180 nm gold nanoparticles. We determined that each of these particles could be modified with ∼75 and ∼330 nanobodies, respectively. Particle-bound nanobodies retain their antigen binding capacity. After conjugation of the mouse Class II MHC-specific nanobody VHH7 to chiral gold nanoparticles, selective targeting of Class II MHC-positive cell types was observed in vitro by fluorometric assays and by dark-field microscopy. Upon installation of the positron emission tomography (PET) isotopes 89Zr or 64Cu on nanobody-modified gold nanoparticles and retro-orbital injection of the radiolabeled particles, we observed accumulation predominantly in the liver and to a far lesser extent in the spleen, regardless of the size of the gold nanoparticles and the identity of the attached nanobody. We observed a striking difference in the distribution of radioisotope-labeled gold nanoparticles by changing the route of administration to intraperitoneal delivery. Significantly reduced accumulation in the liver and spleen was observed by intraperitoneal injection of nanoparticles. In the case of nanobody-modified gold nanoparticles injected intraperitoneally, prominent and persistent signals from the parathymic lymph nodes were observed in the PET/computed tomography images.

Iridium-Cooperated, Symmetry-Broken Manganese Oxide Nanocatalyst for Water Oxidation.

The water oxidation reaction, the most important reaction for hydrogen production and other sustainable chemistry, is efficiently catalyzed by the Mn4CaO5 cluster in biological photosystem II. However, synthetic Mn-based heterogeneous electrocatalysts exhibit inferior catalytic activity at neutral pH under mild conditions. Symmetry-broken Mn atoms and their cooperative mechanism through efficient oxidative charge accumulation in biological clusters are important lessons but synthesis strategies for heterogeneous electrocatalysts have not been successfully developed. Here, we report a crystallographically distorted Mn-oxide nanocatalyst, in which Ir atoms break the space group symmetry from I41/amd to P1. Tetrahedral Mn(II) in spinel is partially replaced by Ir, surprisingly resulting in an unprecedented crystal structure. We analyzed the distorted crystal structure of manganese oxide using TEM and investigated how the charge accumulation of Mn atoms is facilitated by the presence of a small amount of Ir.

Ru-Doped Co3O4 Nanoparticles as Efficient and Stable Electrocatalysts for the Chlorine Evolution Reaction.

The electrochemical chlorine evolution reaction (CER) is one of the most important electrochemical reactions. Typically, iridium (Ir)- or ruthenium (Ru)-based mixed metal oxides have been used as electrocatalysts for the CER due to their high activities and durabilities. However, the scarcity of Ir and Ru has indicated the need to develop alternative earth-abundant transition-metal-based CER catalysts. In this study, we report a Co3O4 nanoparticle (NP) catalyst synthesized by a hydrothermal method. Furthermore, Ru was successfully incorporated into the Co3O4 NPs (RuxCo3-xO4 NPs) for further improvement of catalytic performance in chlorine generation. Electrokinetic analyses combined with in situ X-ray absorption near-edge structure (XANES) results suggested an identical CER mechanism for the Co3O4 NPs and RuxCo3-xO4 NPs. Various characterization techniques demonstrated that the homogeneous substitution of Ru4+ ions into the Co3+ octahedral sites enhanced the structural disorder and changed the electronic state of Co3O4, resulting in additional exposed active sites. Remarkably, the Ru0.09Co2.91O4 NP electrode exhibited outstanding stability for more than 150 h even at a high current density of 500 mA/cm2, which shows its commercial viability for active chlorine generation.

Synergistic effect of Polydopamine incorporated Copper electrocatalyst by dopamine oxidation for efficient hydrogen production.

Tuning the metal-support interaction in electrocatalysts has been proposed as a viable method for manipulating the electronic structure and catalytic activity. In this work, inspired by natural hydrogenase enzyme, electrocatalysts with a hybrid metal-matrix complex using polydopamine (PDA) as a supporting matrix were synthesized for efficient green hydrogen production. Among the various Metal-PDA electrocatalysts, Cu-PDA shows outstanding catalytic activity (low overpotential (ƞ) of 104 mV at 10 mA cm-2 and small Tafel slope of 60.67 mV dec-1) with high stability at neutral pH. Also, the electrochemical impedance spectroscopy analysis verified the fast charge transfer properties of Cu-PDA (2.8 Ω cm2) than PDA (26 Ω cm2), indicating a faster proton-coupled electron transfer process in Cu-PDA electrocatalyst. Therefore, emerging nature inspired organic ligand-transition metal ion complexes can be extensively encouraged as a prospective HER electrocatalyst under neutral conditions.

Strain and crystallographic identification of the helically concaved gap surfaces of chiral nanoparticles.

Identifying the three-dimensional (3D) crystal plane and strain-field distributions of nanocrystals is essential for optical, catalytic, and electronic applications. However, it remains a challenge to image concave surfaces of nanoparticles. Here, we develop a methodology for visualizing the 3D information of chiral gold nanoparticles ≈ 200 nm in size with concave gap structures by Bragg coherent X-ray diffraction imaging. The distribution of the high-Miller-index planes constituting the concave chiral gap is precisely determined. The highly strained region adjacent to the chiral gaps is resolved, which was correlated to the 432-symmetric morphology of the nanoparticles and its corresponding plasmonic properties are numerically predicted from the atomically defined structures. This approach can serve as a comprehensive characterization platform for visualizing the 3D crystallographic and strain distributions of nanoparticles with a few hundred nanometers, especially for applications where structural complexity and local heterogeneity are major determinants, as exemplified in plasmonics.

Hyperreflective foci distribution in eyes with dry age-related macular degeneration with subretinal drusenoid deposits.

PURPOSE: To investigate the distribution of hyperreflective foci (HRF) in eyes with dry age-related macular degeneration (AMD). METHODS: We retrospectively reviewed optical coherence tomography (OCT) images of 58 dry AMD eyes presenting HRF. The distribution of HRF according to the early treatment diabetic retinopathy study area was analyzed according to the presence of subretinal drusenoid deposits (SDDs). RESULTS: We classified 32 eyes and 26 eyes into the dry AMD with SDD group (SDD group) and dry AMD without SDD group (non-SDD group), respectively. The non-SDD group had higher prevalence and density of HRF at the fovea (65.4% and 1.71 ± 1.48) than the SDD group (37.5% and 0.48 ± 0.63, P = 0.035 and P < 0.001, respectively). However, the prevalence and density of HRF in the outer circle area of the SDD group (81.3% and 0.11 ± 0.09) were greater than those of the non-SDD group (53.8% and 0.05 ± 0.06, p = 0.025 and p = 0.004, respectively). The SDD group showed higher prevalence and mean densities of HRF in the superior and temporal area than in the non-SDD group (all, p < 0.05). CONCLUSION: HRF distributions in dry AMD varied according to the presence of SDDs. This might support that the degenerative features may be different between dry AMD eyes with and without SDDs.

Block Copolymer Enabled Synthesis and Assembly of Chiral Metal Oxide Nanoparticle.

Chiral metal oxide nanostructures have received tremendous attention in nanotechnological applications owing to their intriguing chiroptical and magnetic properties. Current synthetic methods mostly rely on the use of amino acids or peptides as chiral inducers. Here, we report a general approach to fabricate chiral metal oxide nanostructures with tunable magneto-chiral effects, using block copolymer (BCP) inverse micelle and R/S-mandelic acid (MA). Diverse chiral metal oxide nanostructures are prepared by the selective incorporation of precursors within micellar cores followed by the oxidation process, exhibiting intense chiroptical properties with a g-factor up to 7.0 × 10-3 in the visible-NIR range for the Cr2O3 nanoparticle multilayer. The BCP inverse micelle is found to inhibit the racemization of MA, allowing MA to act as a chiral dopant that imparts chirality to nanostructures via hierarchical chirality transfer. Notably, for paramagnetic nanostructures, magneto-chiroptical modulation is realized by regulating the direction of the external magnetic field. This BCP-driven approach can be extended to the mass production of chiral nanostructures with tunable architectures and optical activities, which may provide insights into the development of chiroptical functional materials.

A Reflection on Sustainable Anode Materials for Electrochemical Chloride Oxidation.

Chloride oxidation is a key industrial electrochemical process in chlorine-based chemical production and water treatment. Over the past few decades, dimensionally stable anodes (DSAs) consisting of RuO2 - and IrO2 -based mixed-metal oxides have been successfully commercialized in the electrochemical chloride oxidation industry. For a sustainable supply of anode materials, considerable efforts both from the scientific and industrial aspects for developing earth-abundant-metal-based electrocatalysts have been made. This review first describes the history of commercial DSA fabrication and strategies to improve their efficiency and stability. Important features related to the electrocatalytic performance for chloride oxidation and reaction mechanism are then summarized. From the perspective of sustainability, recent progress in the design and fabrication of noble-metal-free anode materials, as well as methods for evaluating the industrialization of novel electrocatalysts, are highlighted. Finally, future directions for developing highly efficient and stable electrocatalysts for industrial chloride oxidation are proposed.