Carboxymethyl chitosan-folic acid-conjugated Fe3O4@SiO2 as a safe and targeting antitumor nanovehicle in vitro

A synthetic method to prepare a core-shell-structured Fe(3)O(4)@SiO(2) as a safe nanovehicle for tumor cell targeting has been developed. Superparamagnetic iron oxide is encapsulated inside nonporous silica as the core to provide magnetic targeting. Carboxymethyl chitosan-folic acid (OCMCS-FA) synthesized through coupling folic acid (FA) with OCMCS is then covalently linked to the silica shell and renders new and improved functions because of the original biocompatible properties of OCMCS and the targeting efficacy of FA. Cellular uptake of the nanovehicle was assayed by confocal laser scanning microscope using rhodamine B (RB) as a fluorescent marker in HeLa cells. The results show that the surface modification of the core-shell silica nanovehicle with OCMCS-FA enhances the internalization of nanovehicle to HeLa cells which over-express the folate receptor. The cell viability assay demonstrated that Fe(3)O(4)@SiO(2)-OCMCS-FA nanovehicle has low toxicity and can be used as an eligible candidate for drug delivery system. These unique advantages make the prepared core-shell nanovehicle promising for cancer-specific targeting and therapy

Charting the Electronic Structure for Discovering Low-cost Intermetallic Catalysts

Discovering affordable, high-performance, and stable catalysts for the hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR) is essential for the commercialization of clean hydrogen technology. In this study, we utilized a high-throughput screening approach combined with electronic structure descriptors to identify new intermetallic catalysts that minimize noble metal contents while maintaining high performance and stability. We screened 2,358 binary and ternary intermetallic compounds constructed from 31 common transition metal elements. From the 462 bulk compositions that are synthetically accessible, we enumerated all possible low-Miller-index surfaces (12,057 surfaces in total) with density functional theory calculations. Seven electronic-structure-based descriptors are then applied to pinpoint aqueously stable surfaces offering performance comparable to the renowned Pt (111) and Ir (111) surfaces. This process led to the identification of several previously known noble-metal-containing catalysts, as well as a selection of new intermetallic catalysts

Design principle of carbon supported single atom catalyst – interplay between d-band periodicity and local hybridization

Carbon-based single atom catalyst has been widely investigated as a potential alternative for noble-metal-based catalysts for hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR). Rationale design of such catalysts require not only physical intuitions but also practical descriptors that can be directly applied in experiments. In this work, we establish a practical theoretical framework based on a comprehensive dataset of single atom catalyst compromising 28 metals, 5 types of local environments and adsorption calculations for 4 adsorbates (e.g., H/O/OH/OOH). We disentangle the complex trend of H/OH adsorption as an interplay between d-band periodicity and local hybridization, allowing for the estimation of catalytic performance based solely on the number of valence electrons. By utilizing this dataset and theoretical framework, we have also identified several promising catalyst candidates and overlooked design strategies

Electrode and Electrolyte Materials From Atomistic Simulations: Properties of LixFEPO4 Electrode and Zircon-Based Ionic Conductors

LixFePO4 orthophosphates and fluorite- and pyrochlore-type zirconate materials are widely considered as functional compounds in energy storage devices, either as electrode or solid state electrolyte. These ceramic materials show enhanced cation exchange and anion conductivity properties that makes them attractive for various energy applications. In this contribution we discuss thermodynamic properties of LixFePO4 and yttria-stabilized zirconia compounds, including formation enthalpies, stability, and solubility limits. We found that at ambient conditions LixFePO4 has a large miscibility gap, which is consistent with existing experimental evidence. We show that cubic zirconia becomes stabilized with Y content of ~8%, which is in line with experimental observations. The computed activation energy of 0.92eV and ionic conductivity for oxygen diffusion in yttria-stabilized zirconia are also in line with the measured data, which shows that atomistic modeling can be applied for accurate prediction of key materials properties. We discuss these results with the existing simulation-based data on these materials produced by our group over the last decade. Last, but not least, we discuss similarities of the considered compounds in considering them as materials for energy storage and radiation damage resistant matrices for immobilization of radionuclides