Synthesis and Electrochemistry of O3-type NaFeO2-NaCo0.5Ni0.5O2 Solid Solutions for Na-Ion Positive Electrodes.

The synthesis, structure, and electrochemistry in Na cells of NaFe xM1- xO2 positive electrode materials with M = Ni, Co0.5Ni0.5, and Co are reported. In particular, the properties of O3-NaFeO2-NaCo0.5Ni0.5O2 solid solutions having compositions NaFe x(Co0.5Ni0.5)1- xO2 with 0 ≤ x ≤ 0.5 are explored. It is found that the substitution of Fe in NaNi0.5Co0.5O2 causes an increase in first cycle energy density from 320 to 440 mWh/g in a 1.5-4.0 V test. However, capacity retention is generally reduced when x is increased for all M = Ni, Co0.5Ni0.5, and Co. In general, NaFe xM1- xO2 samples with M = Co had the highest capacity retention for all values of x. Ex situ X-ray diffraction and Mössbauer results of as-prepared and charged materials are directly compared for NaFe x(Co0.5Ni0.5)1- xO2 and NaFe xCo1- xO2 ( x = 0.4, 0.5). Iron was found to be in the +3 oxidation state in the as-prepared materials. A significant fraction of Fe3+ is oxidized to Fe4+ in these samples when they are charged to 4.0 V.

Epidermal Growth Factor Receptor-Specific Nanoprobe Biodistribution in Mouse Models.

Nanotechnology offers a targeted approach to both imaging and treatment of cancer, the leading cause of death worldwide. Previous studies have found that nanoparticles with a wide variety of coatings initiate an immune response leading to sequestration in the liver and spleen. In an effort to find a nanoparticle platform which does not elicit an immune response, we created 43 nm and 44 nm of gold and silver nanoparticles coated with biomolecules normally produced by the body, α-lipoic acid and the epidermal growth factor (EGF), and have used mass spectroscopy to determine their biodistribution in mouse models, 24 h after tail vein injection. Relative to controls, mouse EGF (mEGF)-coated silver and gold nanoprobes are found at background levels in all organs including the liver and spleen. The lack of sequestration of mEGF-coated nanoprobes in the liver and spleen and the corresponding uptake of control nanoprobes at elevated levels in these organs suggest that the former are not recognized by the immune system. Further studies of cytokine and interleukin levels in the blood are required to confirm avoidance of an immune response.