Oxaliplatin-Loaded Mil-100(Fe) for Chemotherapy-Ferroptosis Combined Therapy for Gastric Cancer.

Oxaliplatin (Oxa) is a commonly used chemotherapy drug in the treatment of gastric cancer, but its toxic side effects and drug resistance after long-term use have seriously limited its efficacy. Loading chemotherapy drugs with nanomaterials and delivering them to the tumor site are common ways to overcome the above problems. However, nanomaterials as carriers do not have therapeutic functions on their own, and the effect of single chemotherapy is relatively limited, so there is still room for progress in related research. Herein, we construct Oxa@Mil-100(Fe) nanocomposites by loading Oxa with a metal-organic framework (MOF) Mil-100(Fe) with high biocompatibility and a large specific surface area. The pore structure of Mil-100(Fe) is conducive to a large amount of Oxa loading with a drug-loading rate of up to 27.2%. Oxa@Mil-100(Fe) is responsive to the tumor microenvironment (TME) and can release Oxa and Fe3+ under external stimulation. On the one hand, Oxa can inhibit the synthesis of DNA and induce the apoptosis of gastric cancer cells. On the other hand, Fe3+ can clear overexpressed glutathione (GSH) in TME and be reduced to Fe2+, inhibiting the activity of glutathione peroxidase 4 (GPX4), leading to the accumulation of intracellular lipid peroxides (LPO), and at the same time releasing a large number of reactive oxygen species (ROS) through the Fenton reaction, inducing ferroptosis in gastric cancer cells. With the combination of apoptosis and ferroptosis, Oxa@Mil-100(Fe) shows a good therapeutic effect, and the killing effect on gastric cancer cells is obvious. In a nude mouse model of subcutaneous tumor transplantation, Oxa@Mil-100(Fe) shows a significant inhibitory effect on tumor growth, with an inhibition rate of nearly 60%. In addition to its excellent antitumor activity, Oxa@Mil-100(Fe) has no obvious toxic or side effects. This study provides a new idea and method for the combined treatment of gastric cancer.

Fabrication of Cu Micromembrane as a Flexible Electrode.

A Cu micromembrane is successfully fabricated and validated as a porous flexible electrode. The Cu micromembrane is prepared by functionalizing individual polypropylene (PP) fibers in a polypropylene micromembrane (PPMM) using a mixture of polydopamine (PDA) and polyethyleneimine (PEI). The mixture of PDA and PEI provides adhesive, wetting, and reducing functionalities that facilitate subsequent Ag activation and Cu electroless plating. Scanning electron microscopy reveals conformal deposition of Cu on individual PP fibers. Porometer analysis indicates that the porous nature of PPMM is properly maintained. The Cu micromembrane demonstrates impressive electrical conductivities in both the X direction (1.04 ± 0.21 S/cm) and Z direction (2.99 ± 0.54 × 10-3 S/cm). In addition, its tensile strength and strain are better than those of pristine PPMM. The Cu micromembrane is flexible and mechanically robust enough to sustain 10,000 bending cycles with moderate deterioration. Thermogravimetric analysis shows a thermal stability of 400 °C and an effective Cu loading of 5.36 mg/cm2. Cyclic voltammetric measurements reveal that the Cu micromembrane has an electrochemical surface area of 277.8 cm2 in a 1 cm2 geometric area (a roughness factor of 227.81), a value that is 45 times greater than that of planar Cu foil.

A flexible IrO2 membrane for pH sensing.

An optimized mixture of polydopamine (PDA) and polyvinyl alcohol (PVA) is employed as the surface functionalizing agent and reducing agent to encapsulate individual polypropylene (PP) fibers of polypropylene micromembrane (PPMM). The functionalized PPMM becomes hydrophilic to allow the formation of Au nuclei for subsequent electroless Au deposition. The metalized PPMM is further deposited with IrO2 nanoparticles, and evaluated as a flexible and porous pH sensor. Images from scanning electron microscope confirms the uniform formation of IrO2 nanoparticles on Au-coated PP fibers. For pH-sensing performance, the IrO2-decorated metalized PPMM reveals a super-Nernstian response for a sensing slope of -74.45 mV/pH in aqueous solutions with pH value ranging between 2 and 12. In addition, the pH-sensing performance is properly maintained after 5000 bending cycles and hysteresis is modest in an acidic environment. The cell viability test indicates a negligible bio-toxicity. Our strategy of using a conductive polymeric membrane decorated with IrO2 nanoparticles enables possible sensing applications in wearable and implantable electronics.

Self-healable and anti-freezing ion conducting hydrogel-based artificial bioelectronic tongue sensing toward astringent and bitter tastes.

Numerous efforts have been attempted to mimic human tongue since years. However, they still have limitations because of damages, temperature effects, detection ranges etc. Herein, a self-healable hydrogel-based artificial bioelectronic tongue (E-tongue) containing mucin as a secreted protein, sodium chloride as an ion transporting electrolyte, and chitosan/poly(acrylamide-co-acrylic acid) as the main 3D structure holding hydrogel network is synthesized. This E-tongue is introduced to mimic astringent and bitter mouth feel based on cyclic voltammetry (CV) measurements subjected to target substances, which permits astringent tannic acid (TA) and bitter quinine sulfate (QS) to be detected over wide corresponding ranges of 29.3 mM-0.59 µM and 63.8 mM-6.38 µM with remarkable respective sensitivities of 0.2 and 0.12 wt%-1. Besides, the taste selectivity of this E-tongue is performed in the presence of various mixed-taste chemicals to show its high selective behavior toward bitter and astringent chemicals. The electrical self-healability is shown via CV responses to illustrate electrical recovery within a short time span. In addition, cytotoxicity tests using HeLa cells are performed, where a clear viability of ≥95% verified its biocompatibility. The anti-freezing sensing of E-tongue tastes at -5 °C also makes this work to be useful at sub-zero environments. Real time degrees of tastes are detected using beverages and fruits to confirm future potential applications in food taste detections and humanoid robots.

An Efficient Symmetric Electrolyzer Based On Bifunctional Perovskite Catalyst for Ammonia Electrolysis.

Ammonia is a natural pollutant in wastewater and removal technique such as ammonia electro-oxidation is of paramount importance. The development of highly efficient and low-costing electrocatalysts for the ammonia oxidation reaction (AOR) and hydrogen evolution reaction (HER) associated with ammonia removal is subsequently crucial. In this study, for the first time, the authors demonstrate that a perovskite oxide LaNi0.5 Cu0.5 O3-δ after being annealed in Ar (LNCO55-Ar), is an excellent non-noble bifunctional catalyst towards both AOR and HER, making it suitable as a symmetric ammonia electrolyser (SAE) in alkaline medium. In contrast, the LNCO55 sample fired in air (LNCO55-Air) is inactive towards AOR and shows very poor HER activity. Through combined experimental results and theoretical calculations, it is found that the superior AOR and HER activities are attributed to the increased active sites, the introduction of oxygen vacancies, the synergistic effect of B-site cations and the different active sites in LNCO55-Ar. At 1.23 V, the assembled SAE demonstrates ≈100% removal efficiency in 2210 ppm ammonia solution and >70% in real landfill leachate. This work opens the door for developments towards bifunctional catalysts, and also takes a profound step towards the development of low-costing and simple device configuration for ammonia electrolysers.

N,N-Dimethylacetamide-Diluted Nitrate Electrolyte for Aqueous Zn//LiMn2O4 Hybrid Ion Batteries.

N,N-Dimethylacetamide (DMA) cooperated with LiNO3 salt has previously shown to be a promising electrolyte for a Li//O2 battery, showing good stability against both the O2 electrode reaction and Li stripping/plating. In this work, DMA is hybridized with a concentrated nitrate electrolyte [2.5 m Zn(NO3)2 + 13 m LiNO3 aqueous solution] for better electrochemical stability while using less dissolved salts. The widest electrochemical stability window for this DMA-diluted electrolyte is determined as 3.1 V, the negative critical stability potential of which is -1.6 V versus Ag/AgCl, indicating desirable stability against hydrogen evolution and Zn deposition. The findings can be attributed to the weakened Li+/Zn2+ solvation sheath caused by low permittivity of DMA, as revealed through Raman spectra characterization and molecular dynamics simulation. A Zn//Zn symmetrical cell and Zn//LiMn2O4 hybrid ion batteries are assembled in air directly, attributed to the stability of DMA toward O2. Zn stripping/plating with a dendrite-free morphology is delivered for 110 h and 200 charge/discharge cycles under 1 C rate, achieving 99.0% Coulombic efficiency. The maximum capacity of the battery is 121.0 mA h·g-1 under 0.2 C rate (based on the mass of LiMn2O4), delivering an energy density of 165.8 W h·kg-1 together with 2.0 V working voltage. This work demonstrates the feasibility and validity of utilizing a relatively dilute electrolyte dissolved in oxygen for a highly stable aqueous rechargeable battery.

Facile Synthesis of Co3O4@CoO@Co Gradient Core@Shell Nanoparticles and Their Applications for Oxygen Evolution and Reduction in Alkaline Electrolytes.

We demonstrate a facile fabrication scheme for Co3O4@CoO@Co (gradient core@shell) nanoparticles on graphene and explore their electrocatalytic potentials for an oxygen evolution reaction (OER) and an oxygen reduction reaction (ORR) in alkaline electrolytes. The synthetic approach begins with the preparation of Co3O4 nanoparticles via a hydrothermal process, which is followed by a controlled hydrogen reduction treatment to render nanoparticles with radial constituents of Co3O4/CoO/Co (inside/outside). X-ray diffraction patterns confirm the formation of crystalline Co3O4 nanoparticles, and their gradual transformation to cubic CoO and fcc Co on the surface. Images from transmission electron microscope reveal a core@shell microstructure. These Co3O4@CoO@Co nanoparticles show impressive activities and durability for OER. For ORR electrocatalysis, the Co3O4@CoO@Co nanoparticles are subjected to a galvanic displacement reaction in which the surface Co atoms undergo oxidative dissolution for the reduction of Pt ions from the electrolyte to form Co3O4@Pt nanoparticles. With commercial Pt/C as a benchmark, we determine the ORR activities in sequence of Pt/C > Co3O4@Pt > Co3O4. Measurements from a rotation disk electrode at various rotation speeds indicate a 4-electron transfer path for Co3O4@Pt. In addition, the specific activity of Co3O4@Pt is more than two times greater than that of Pt/C.

Different Effects of Fluoride Exposure on the Three Major Bone Cell Types.

Fluoride accumulates and is toxic to bones. Clinical bone lesions occur in a phased manner, being less severe early in the natural course of skeletal fluorosis. Previous research rarely focused on osteocyte, osteoclast, and osteoblast at the same time, although these three types of cells are involved in the process of fluorosis. In this study, commitment of bone cells was performed according to their respective characteristics. Osteocyte-like cells were verified by protein expression of sclerostin (SOST) in IDG-SW3 cell culture with mineral medium. Positive tartrate-resistant acid phosphatase (TRACP) staining, characteristic of osteoclasts, is observed in RAW264.7 cells after administration of RANKL. We successfully purified a high percentage (94%) of bone mesenchymal stem cells (BMSCs) co-expressing CD34 and CD44. Parallel studies were performed to observe cell viability and apoptosis rates in osteocyte, osteoclast, and osteoblast like cells by using MTT and Annexin V FITC assays. Our results demonstrated that osteocytes have a strong tolerance to high fluoride concentrations, while osteoclasts are more sensitive to changes of fluoride dose. The range of anabolic action of fluoride concentration on osteoblast was narrow. Notably, fluoride exposure aggravated apoptosis of osteocyte and osteoclast induced by administration of PTH and TGF-ß, respectively. In short, three types of bone cells display disparate responses to fluoride exposure and to PTH- and TGF-ß-induced apoptosis.