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In this study, Ag is electron-beam evaporated to modify the topography of anodic TiO2 nanotubes of different diameters to obtain an implant with enhanced antibacterial activity and biocompatibility. We found that highly hydrophilic as-grown TiO2 nanotubes became poorly hydrophilic with Ag incorporation; however they could effectively recover their wettability to some extent under ultraviolet light irradiation. The results obtained from antibacterial tests suggested that the Ag-decorated TiO2 nanotubes could greatly inhibit the growth of Staphylococcus aureus. In vitro biocompatibility evaluation indicated that fibroblast cells exhibited an obvious diameter-dependent behavior on both as-grown and Ag-decorated TiO2 nanotubes. Most importantly, of all samples, the smallest diameter (25-nm-diameter) Ag-decorated nanotubes exhibited the most obvious biological activity in promoting adhesion and proliferation of human fibroblasts, and this activity could be attributed to the highly irregular topography on a nanometric scale of the Ag-decorated nanotube surface. These experimental results demonstrate that by properly controlling the structural parameters of Ag-decorated TiO2 nanotubes, an implant surface can be produced that enhances biocompatibility and simultaneously boosts antibacterial activity.

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A high-voltage LiNi 0.5 Mn 1.5 O 4 cathode material with a cubic spinel structure is synthesized using a citricacid-assisted sol-gel process. Butylmethylpyrrolidinium bis(trifluoromethanesulfonyl)imide (BMP-TFSI)based ionic liquids (ILs) with various kinds of Li salts, namely LiTFSI, LiPF 6 , and their mixtures, are used as electrolytes for Li/LiNi 0.5 Mn 1.5 O 4 cells. The IL electrolytes show high thermal stability (>400 C) and nonflammability, and are thus ideal for high-safety applications. At 25 C, LiTFSI is more suitable than LiPF 6 as an IL electrolyte in terms of cell capacity, rate capability, and cyclic stability. The IL electrolytes clearly outperform the conventional organic electrolytes at 50 C, since the latter decomposes at high voltage and corrodes both the Al current collector and LiNi 0.5 Mn 1.5 O 4 , degrading the electrode performance. At such an elevated temperature, using LiPF 6 to partially substitute LiTFSI in the IL electrolyte can effectively suppress Al pitting corrosion and thus improves the cell performance. In the 0.4 M LiTFSI/0.6 M LiPF 6 mixed-salt IL electrolyte, an LiNi 0.5 Mn 1.5 O 4 discharge capacity of 115 mA h g À1 (at 0.1 C) is obtained at 50 C with a high cell voltage of $4.7 V.