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Carbon-supported nanoparticles have been used widely as efficient catalysts due to their enhanced surface-to-volume ratio. To investigate their structure–property relationships, acquiring 3D elemental distribution is required. Here, carbon-supported Pt, PtMn alloy, and ordered Pt3Mn nanoparticles are synthesized and analyzed with atom probe tomography as model systems. A significant difference of Mn distribution after the heat-treatment was found. Finally, the field evaporation behavior of the carbon support was discussed and each acquired reconstruction was compared with computational results from an evaporation simulation. This paper provides a guideline for studies using atom probe tomography on the heterogeneous carbon-supported nanoparticle system that leads to insights toward a wide variety of applications.

To advance the understanding of the degradation of the liquid electrolyte and Si electrode, and their interface, we exploit the latest developments in cryo-atom probe tomography. We evidence Si anode corrosion from the decomposition of the Li salt before charge-discharge cycles even begin. Volume shrinkage during delithiation leads to the development of nanograins from recrystallization in regions left amorphous by the lithiation. The newly created grain boundaries facilitate pulverization of nanoscale Si fragments, and one is found floating in the electrolyte. P is segregated to these grain boundaries, which confirms the decomposition of the electrolyte. As structural defects are bound to assist the nucleation of Li-rich phases in subsequent lithiations and accelerate the electrolyte's decomposition, these insights into the developed nanoscale microstructure interacting with the electrolyte contribute to understanding the self-catalyzed/accelerated degradation Si anodes and can inform new battery designs unaffected by these life-limiting factors.

Supplementary Figure 2. The EGFR-GC1118 interaction is not disrupted by excess amounts of high- or low-affinity EGFR ligands. The indicated colorectal cancer cell lines were pre-incubated with 0.1 ug/ml of cetuximab or GC1118 for 2 h prior to the addition of EGFR ligands for 10 min (EGF, HB-EGF, BTC, and TGF-�, 20~500 ng/ml; AREG and EREG, 40~1000 ng/ml). The blue and red lines indicate the relative % of cetuximab and GC1118, respectively, bound to EGFR in the presence of competing ligands compared with bound antibodies in the absence of blocking ligands. Antibody binding to EGFR was assessed by measuring the fluorescence intensity using flow cytometry. The results are expressed as the average{plus minus}SE of % maximal binding of the antibody of triplicate experiments.

Supplementary Figure 1. Kinetic binding interactions between GC1118 and EGFR as analyzed by SPR. SPR sensorgrams were obtained from injections of (A) GC1118 or (B) cetuximab over an EGFR-immobilized surface at a flow rate of 30 µl/min. The results of a quantitative evaluation of the experimental data are shown in Supplementary Table 2.

The limited localization and penetration of monoclonal antibodies (mAb) into solid tumors restricts their antitumor efficacy. Here, we describe a solid tumor–targeting antibody with enhanced tumor penetration activity. We designed a 22-residue peptide (A22p), which was extracted from the C-terminal basic region of semaphorin 3A (Sema3A) but modified to have higher affinity with neuropilin receptors (NRP), and genetically fused it to the C-terminus of Fc of human immunoglobulin G1 via a 15-residue (G4S)3 linker, generating Fc-A22p, for the bivalent binding to NRPs. In contrast to Fc or the monovalent A22p peptide alone, Fc-A22p homed to tumor vessels and induced vascular permeability through VE-cadherin downregulation and penetrated tumor tissues by interacting with NRPs in mice bearing human tumor xenografts. We extended the Fc-A22p platform by generating mAb-A22p antibodies of two clinically approved solid tumor–targeting mAbs, the anti-EGF receptor mAb cetuximab (erbitux), and the anti-Her2 mAb trastuzumab (herceptin). The mAb-A22p antibodies retained the intrinsic antigen binding, natural Fc-like biophysical properties, and productivity in mammalian cell cultures, comparable with those of the parent mAbs. In mouse xenograft tumor models, the mAb-A22p antibodies more efficiently homed to tumor vessels and spread into the extravascular tumor parenchyma, which significantly enhanced antitumor efficacy compared with the parent mAbs. Our results suggest that mAb-A22p is a superior format for solid tumor–targeting antibodies due to its enhanced tumor tissue penetration and greater antitumor efficacy compared with conventional mAbs. Mol Cancer Ther; 13(3); 651–61. ©2014 AACR.

PDF - 2613K, Figure S1: Structural analysis of NRP1, NRP2, and Sema3A, and their interactions to facilitate the understanding of the interactions between Sema3A and NRP1/2. Figure S2: SDS-PAGE analyses of the purified proteins showing that NRP1/2-b1b2 domains, Fc-A22, and Fc-A22p are well prepared. Figure S3: FACS and confocal fluorescence data showing that Fc-A22p, but not Fc, specifically interacts with cell-surface expressed NRP1/2 undergoing cellular internalization. Figure S4: Cell viability data showing that Fc-A22p does not cause significant cytotoxicity on HUVECs and tumor cells. Figure S5: Tumor tissue analyzing data showing that Fc-A22p homes to tumor, induces vascular permeability, and downregulates VE-cadherin in endothelial cells and E-cadherin in tumor cells. Figure S6: Confocal fluorescence data showing that Fc-A22p causes downregulation of VE-/E-cadherin and their dissociation from F-actin cytoskeleton resulting in disruption of cell-cell contacts. Figure S7: Data showing the expression and biochemical characterization of mAb-A22p antibodies, cetuximab-A22p and trastuzumab-A22p, compared with the parent mAbs. Figure S8: Cell proliferation and Western blotting data showing that cetuximab-A22p exerts in vitro biological activities comparable to those of cetuximab in A431 and FaDu tumor cells. Figure S9: Human tumor xenografted mouse data showing that mAb-A22p antibodies show increased tumor homing and penetration and thus superior in vivo anti-tumor efficacy, compared with the parent mAbs. Table S1: SPR data showing the kinetic binding parameters for the interactions of Fc-A22, Fc-A22p, VEGF165, and Sema3A with soluble NRP1-b1b2 and NRP2-b1b2 fragments. Table S2: Purification yields of Fc proteins and antibodies obtained from transient expression in HEK293F cells. Table S3: SPR data showing the kinetic binding parameters for the interactions of mAbs and mAb-A22p antibodies with the indicated proteins. Supplementary Materials and Methods: Detailed description of Reagents; Recombinant protein expression and purification; Construction, expression, and purification of antibodies; Binding analysis by ELISA; Surface plasmon resonance (SPR); Flow cytometric analysis; Cell proliferation assay; Western blotting and immunoprecipitation; Co-localization studies by confocal immunofluorescence microscopy; RNA Interference; Ex vivo tumor penetration assays.

Supplementary Table 1. X-ray data collection and refinement statistics.

Surface plasmon resonance (SPR)

Capping ligands are crucial to synthesizing colloidal nanoparticles with functional properties. However, the synergistic effect between different ligands and their distribution on crystallographic surfaces of nanoparticles during colloidal synthesis is still unclear despite powerful spectroscopic techniques, due to a lack of direct imaging techniques. In this study, atom probe tomography is adopted to investigate the three-dimensional atomic-scale distribution of two of the most common types of these ligands, cetrimonium (C19H42N) and halide (Br and Cl) ions, on Pd nanoparticles. The results, validated using density functional theory, demonstrate that the Br anions adsorbed on the nanoparticle surfaces promote the adsorption of the cetrimonium cations through electrostatic interactions, stabilizing the Pd {111} facets. In contrast, the Cl anions are not strongly adsorbed onto the Pd surfaces. The high density of adsorbed cetrimonium cations for Br anion additions results in the formation of multiple-twinned nanoparticles with superior oxidation resistance., Despite the important role of ligands in designing nanoparticles, directly imaging them on the nanoparticle surface remains a challenge. Here, the authors use atom probe tomography to map the spatial distribution of ligands on nanoparticles and reveal that the interplay between halide and cetrimonium ligands decides the oxidation resistance and shape of Pd nanoparticles.

Bimetallic nanoparticles are often superior candidates for a wide range of technological and biomedical applications owing to their enhanced catalytic, optical, and magnetic properties, which are often better than their monometallic counterparts. Most of their properties strongly depend on their chemical composition, crystallographic structure, and phase distribution. However, little is known of how their crystal structure, on the nanoscale, transforms over time at elevated temperatures, even though this knowledge is highly relevant in case nanoparticles are used in, e.g., high-temperature catalysis. Au-Fe is a promising bimetallic system where the low-cost and magnetic Fe is combined with catalytically active and plasmonic Au. Here, we report on the in situ temporal evolution of the crystalline ordering in Au-Fe nanoparticles, obtained from a modern laser ablation in liquids synthesis. Our in-depth analysis, complemented by dedicated atomistic simulations, includes a detailed structural characterization by X-ray diffraction and transmission electron microscopy as well as atom probe tomography to reveal elemental distributions down to a single atom resolution. We show that the Au-Fe nanoparticles initially exhibit highly complex internal nested nanostructures with a wide range of compositions, phase distributions, and size-depended microstrains. The elevated temperature induces a diffusion-controlled recrystallization and phase merging, resulting in the formation of a single face-centered-cubic ultrastructure in contact with a body-centered cubic phase, which demonstrates the metastability of these structures. Uncovering these unique nanostructures with nested features could be highly attractive from a fundamental viewpoint as they could give further insights into the nanoparticle formation mechanism under non-equilibrium conditions. Furthermore, the in situ evaluation of the crystal structure changes upon heating is potentially relevant for high-temperature process utilization of bimetallic nanoparticles, e.g., during catalysis.

Atom probe tomography has been raising in prominence as a microscopy and microanalysis technique to gain sub-nanoscale information from technologically-relevant materials. However, the analysis of some functional ceramics, particularly perovskites, has remained challenging with extremely low yield and success rate. This seems particularly problematic for materials with high piezoelectric activity, which may be difficult to express at the low temperatures necessary for satisfactory atom probe analysis. Here, we demonstrate the analysis of commercial BaTiO3 particles embedded in a metallic matrix. Density-functional theory shows that a metallic coating prevents charge penetration of the electrostatic field, and thereby suppresses the associated volume associated change linked to the piezoelectric effect.

Mesenchymal stem cell (MSC)-based therapy using gene delivery systems has been suggested for degenerative diseases. Although MSC-based clinical applications are effective and safe, the mode of action remains unclear. Researchers have commonly applied viral-based gene modification because this system has efficient vehicles. While viral transfection carries many risks, such as oncogenes and chromosomal integration, nonviral gene delivery techniques are less expensive, easier to handle, and safe, although they are less efficient. The electroporation method, which uses Nucleofection technology, provides critical opportunities for hard-to-transfect primary cell lines, including MSCs. Therefore, to improve the therapeutic efficacy using genetically modified MSCs, researchers must determine the optimal conditions for the introduction of the Nucleofection technique in MSCs. Here, we suggest optimal methods for gene modification in PD-MSCs using an electroporation gene delivery system for clinical application.

Hydrogen embrittlement can cause a dramatic deterioration of the mechanical properties of high-strength metallic materials. Despite decades of experimental and modelling studies, the exact underlying mechanisms behind hydrogen embrittlement remain elusive. To unlock understanding of the mechanism and thereby help mitigate the influence of hydrogen and the associated embrittlement, it is essential to examine the interactions of hydrogen with structural defects such as grain boundaries, dislocations and stacking faults. Atom probe tomography (APT) can, in principle, analyse hydrogen located specifically at such microstructural features but faces strong challenges when it comes to charging specimens with hydrogen or deuterium. Here, we describe three different workflows enabling hydrogen/deuterium charging of site-specific APT specimens: namely cathodic, plasma and gas charging. All the experiments in the current study have been performed on a model twinning induced plasticity steel alloy. We discuss in detail the caveats of the different approaches in order to help future research efforts and facilitate further studies of hydrogen in metals. Our study demonstrates successful cathodic and gas charging, with the latter being more promising for the analysis of the high-strength steels at the core of our work.

When solid-state redox-driven phase transformations are associated with mass loss, vacancies are produced that develop into pores. These pores can influence the kinetics of certain redox and phase transformation steps. We investigated the structural and chemical mechanisms in and at pores in a combined experimental-theoretical study, using the reduction of iron oxide by hydrogen as a model system. The redox product (water) accumulates inside the pores and shifts the local equilibrium at the already reduced material back towards re-oxidation into cubic-Fe1-xO (where x refers to Fe deficiency, space group Fm3-m). This effect helps to understand the sluggish reduction of cubic-Fe1-xO by hydrogen, a key process for future sustainable steelmaking.

Fuel cells recombine water from H-2 and O-2 thereby can power, for example, cars or houses with no direct carbon emission. In anion-exchange membrane fuel cells (AEMFCs), to reach high power densities, operating at high pH is an alternative to using large volumes of noble metals catalysts at the cathode, where the oxygen-reduction reaction occurs. However, the sluggish kinetics of the hydrogen-oxidation reaction (HOR) hinders upscaling despite promising catalysts. Here, the authors observe an unexpected ingress of B into Pd nanocatalysts synthesized by wet-chemistry, gaining control over this B-doping, and report on its influence on the HOR activity in alkaline conditions. They rationalize their findings using ab initio calculations of both H- and OH-adsorption on B-doped Pd. Using this "impurity engineering" approach, they thus design Pt-free catalysts as required in electrochemical energy conversion devices, for example, next generations of AEMFCs, that satisfy the economic and environmental constraints, that is, reasonable operating costs and long-term stability, to enable the "hydrogen economy."

Journal of the American Chemical Society 144(2), 987-994 (2022). doi:10.1021/jacs.1c11680, Published by American Chemical Society, Washington, DC

MRS bulletin (2022). doi:10.1557/s43577-022-00373-8, Published by Springer, Berlin

Alcohol consumption causes the accumulation of reactive oxygen species in liver, which leads to alcoholic fatty liver and hepatocyte injury. In this study, we investigated the effects of an ethanolic Citrus depressa extract and those of its main components on alcohol-induced liver damage using a mouse model. Four polymethoxylated flavonoids, namely, nobiletin, tangeretin, 5-O-demethylnobiletin, and sinensetin, were isolated from C. depressa extract. Treatment of ethanol fed mice with C. depressa extract, nobiletin, tangeretin, or 5-O-demethylnobiletin at 300 mg/kg for 8 weeks by oral administration alleviated the accumulation of lipid droplets in liver and significantly decreased the serum levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) (markers of liver damage). Also, in mice treated with ethanol plus nobiletin, tangeretin, or 5-O-demethylnobiletin, liver level of glutathione (an antioxidant) increased whereas levels of tumor necrosis factor-alpha (TNF-α), hepatic malondialdehyde, and hepatic cytochrome P450 2E1 (CYP2E1) mRNA decreased as compared with ethanol fed controls. These findings suggest C. depressa extract and polymethoxylated flavonoids had a protective effect on alcohol-induced liver injury, and that the mechanism involved is related to the regulation of hepatic CYP2E1-mediated oxidative stress.

The worldwide development of electric vehicles as well as large-scale or grid-scale energy storage to compensate for the intermittent nature of renewable energy generation has led to a surge of interest in battery technology. Understanding the factors controlling battery capacity and, critically, their degradation mechanisms to ensure long-term, sustainable and safe operation requires detailed knowledge of their microstructure and chemistry, and their evolution under operating conditions, on the nanoscale. Atom probe tomography (APT) provides compositional mapping of materials in three dimensions with sub-nanometre resolution, and is poised to play a key role in battery research. However, APT is underpinned by an intense electric field that can drive lithium migration, and many battery materials are reactive oxides, requiring careful handling and sample transfer. Here, we report on the analysis of both anode and cathode materials and show that electric-field driven migration can be suppressed by using shielding by embedding powder particles in a metallic matrix or by using a thin conducting surface layer. We demonstrate that for a typical cathode material, cryogenic specimen preparation and transport under ultra-high vacuum leads to major delithiation of the specimen during the analysis. In contrast, the transport of specimens through air enables the analysis of the material. Finally, we discuss the possible physical underpinnings and discuss ways forward to enable shielding from the electric field, which helps address the challenges inherent to the APT analysis of battery materials.

Background Cholesterol accumulation and calcium depletion induce hepatic injury via the endoplasmic reticulum (ER) stress response. ER stress regulates the calcium imbalance between the ER and mitochondria. We previously reported that phosphatase of regenerating liver-1 (PRL-1)-overexpressing placenta-derived mesenchymal stem cells (PD-MSCsPRL−1) promoted liver regeneration via mitochondrial dynamics in a cirrhotic rat model. However, the role of PRL-1 in ER stress-dependent calcium is not clear. Therefore, we demonstrated that PD-MSCsPRL−1 improved hepatic functions by regulating ER stress and calcium channels in a rat model of bile duct ligation (BDL). Methods Liver cirrhosis was induced in Sprague–Dawley (SD) rats using surgically induced BDL for 10 days. PD-MSCs and PD-MSCsPRL−1 (2 × 106 cells) were intravenously administered to animals, and their therapeutic effects were analyzed. WB-F344 cells exposed to thapsigargin (TG) were cocultured with PD-MSCs or PD-MSCsPRL−1. Results ER stress markers, e.g., eukaryotic translation initiation factor 2α (eIF2α), activating transcription factor 4 (ATF4), and C/EBP homologous protein (CHOP), were increased in the nontransplantation group (NTx) compared to the control group. PD-MSCsPRL−1 significantly decreased ER stress markers compared to NTx and induced dynamic changes in calcium channel markers, e.g., sarco/endoplasmic reticulum Ca2+ -ATPase 2b (SERCA2b), inositol 1,4,5-trisphosphate receptor (IP3R), mitochondrial calcium uniporter (MCU), and voltage-dependent anion channel 1 (VDAC1) (*p PRL−1 decreased cytosolic calmodulin (CaM) expression and cytosolic and mitochondrial Ca2+ concentrations. However, the ER Ca2+ concentration was increased compared to PD-MSCs (*p Conclusions These findings suggest that PD-MSCsPRL−1 improved hepatic functions via calcium changes and attenuated ER stress in a BDL-injured rat model. Therefore, these results provide useful data for the development of next-generation MSC-based stem cell therapy for regenerative medicine in chronic liver disease.

Background: Accumulation of cholesterol and depletion of calcium induce hepatic injury through the endoplasmic reticulum (ER) stress response. ER stress regulates the calcium imbalance between the ER and mitochondria. Previously, we reported that phosphatase of regenerating liver-1 (PRL-1)-overexpressing placenta-derived mesenchymal stem cells (PD-MSCsPRL-1) promoted liver regeneration through mitochondrial dynamics in a cirrhotic rat model. However, whether PRL-1 is involved in ER stress-dependent calcium is unclear. So, we demonstrated that PD-MSCsPRL-1 improves hepatic functions by regulating ER stress and calcium channels in a rat model of bile duct ligation (BDL). Methods: Liver cirrhosis was induced in Sprague-Dawley (SD) rats using surgically induced BDL for 10 days. PD-MSCs and PD-MSCsPRL-1 (2x106 cells) were intravenously administered to animals, and their therapeutic effects were analyzed. WB-F344 cells exposed to thapsigargin (TG) were cocultured with PD-MSCs or PD-MSCsPRL-1. Results: ER stress markers (e.g., eIF2α, ATF4, and CHOP) were increased in the non-transplantation group (NTx) compared with the control group. PD-MSCsPRL-1 significantly decreased ER stress markers compared to NTx and induced dynamic changes in calcium channel markers (e.g., SERCA2b, IP3R, MCU, and VDAC1) (*pPRL-1 decreased cytosolic CaM expression and cytosolic and mitochondrial Ca2+ concentrations; however, the ER Ca2+ concentration was increased compared to that in PD-MSCs (*pConclusions: These findings suggest that PD-MSCsPRL-1 improved hepatic functions through calcium changes and attenuated ER stress in a BDL-injured rat model. Therefore, these results provide useful data for the development of next-generation MSC-based stem cell therapy for regenerative medicine in chronic liver disease.