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PACS 81.05. Dz, 81.16.Bc Cadmium selenide nanoparticles (CdSe NPs) were synthesized in the cavity of the cage-shaped protein, apoferritin, by designing a slow chemical reaction, which employs tetraamminecadmium ion and selenourea. The ammonia water concentration and solution pH were optimized and the suppression of the formation of selenium oxide was also studied by deoxydation of the reaction solution. At the concentration of 5 mM ammonia water and at pH 9.5, with N 2 gas bubbling, the core formation ratio (CFR) of CdSe NPs reached 75% and yield of protein ratio (YPR) was as high as 98%. N 2 gas bubbling of reaction solution was found to be critical for the high CFR and high YPR of the CdSe NPs synthesis in apoferritin cavity. Using this optimized conditions, high quality CdSe NPs were obtained by the bio-template, apoferritin protein method.

Zerovalent copper nanoparticles (CuNPs) (diameter, 26.5 ± 9 nm) capped with polyvinylpyrrolidone (PVP) were synthesized in supercritical water at 400 °C and 30 MPa with a continuous flow reactor. The PVP-capped CuNPs were dispersed in distilled water, methanol, ethanol, 1-propanol, 2-propanol, butanol, and their mixed solvents to study their long-term stability. Temporal variation of UV-vis spectra and surface plasmon resonance were measured and showed that ethanol, the propanols, and butanol solvents provided varying degrees of oxidative protection for Cu(0). Fourier transform infrared spectroscopy showed that PVP adsorbed onto the surface of the CuNPs with a pyrrolidone ring of PVP even if the CuNPs were oxidized. Intrinsic viscosities of PVP were higher for solvents that provided antioxidation protection than those that give oxidized CuNPs. In solvents that provided Cu(0) with good oxidative protection (ethanol, the propanols, and butanol), PVP polymer chains formed large radii of gyration and coil-like conformations in the solvents so that they were arranged uniformly and orderly on the surface of the CuNPs and could provide protection of the Cu(0) surface against dissolved oxygen. In solvents that provided poor oxidative protection for Cu(0) (water, alcohol-water mixed solvents with 30% water), PVP polymer chains had globular-like conformations due to their relatively high hydrogen-bonding interactions and sparse adsorption onto the CuNP surface. Antioxidative properties of PVP-capped CuNPs in a solvent can be ascribed to the conformation of PVP polymer chains on the Cu(0) particle surface that originates from the interaction between polymer chains and its interaction with the solvent.

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SAISTINARC.4MRLIPunasonic 2P554Elucidation of the Mechanism of CdSe Nano Particles Synthesis in the Apoferritin Cavity 'C).'Taku}'a Morioka', Kenji lwahori2, Ichire Yhmushituii'3 "NAIST, :CREST, .]apan Science and Technolog)' Agency, ]MRJ.