Showing papers by "Yue Wu published in 2013"

Graphene-hollow PPy sphere 3D-nanoarchitecture with enhanced electrochemical performance.

Abstract: A rationally designed graphene–hollow polypyrrole (PPy) nanoarchitecture in which hollow PPy spheres were inserted between graphene layers was constructed by mixing graphene oxide and polystyrene (PS)@PPy core–shell sphere, followed by reduction of graphene oxide and etching of PS. The as-prepared graphene–hollow PPy nanoarchitecture was explored as electrode material for supercapacitor applications. The specific capacitance may gradually rise to as high as 500 F g−1 with a charging/discharging current density of 5 A g−1, and remains stable even after 10 000 cycles. Analysis indicates that the tailored nanoarchitecture enhances specific area of the electrode and promotes synergetic effect between RGO and PPy, thus leading to a significantly enhanced electrochemical performance.

Self-assembly of protein-based biomaterials initiated by titania nanotubes

Abstract: Protein-based biomaterials are a promising strategy for creating robust highly selective biocatalysts. The assembled biomaterials must sufficiently retain the near-native structure of proteins and provide molecular access to catalytically active sites. These requirements often exclude the use of conventional assembly techniques, which rely on covalent cross-linking of proteins or entrapment within a scaffold. Here we demonstrate that titania nanotubes can initiate and template the self-assembly of enzymes, such as ribonuclease A, while maintaining their catalytic activity. Initially, the enzymes form multilayer thick ellipsoidal aggregates centered on the nanotube surface; subsequently, these nanosized entities assemble into a micrometer-sized enzyme material that has enhanced enzymatic activity and contains as little as 0.1 wt % TiO2 nanotubes. This phenomenon is uniquely associated with the active anatase (001)-like surface of titania nanotubes and does not occur on other anatase nanomaterials, which contain significantly fewer undercoordinated Ti surface sites. These findings present a nanotechnology-enabled mechanism of biomaterial growth and open a new route for creating stable protein-based biomaterials and biocatalysts without the need for chemical modification.

Critical role of water in the binding of volatile anesthetics to proteins.

Abstract: Numerous small molecules exhibit drug-like properties by low-affinity binding to proteins. Such binding is known to be influenced by water, the detailed picture of which, however, remains unclear. One particular example is the controversial role of water in the binding of general anesthetics to proteins as an essential step in general anesthesia. Here we demonstrate that a critical amount of hydration water is a prerequisite for anesthetic–protein binding. Using nuclear magnetic resonance, the concurrent adsorption of hydration water and bound anesthetics on model proteins are simultaneously measured. Halothane binding on proteins can only take place after protein hydration reaches a threshold hydration level of ∼0.31 g of water/g of proteins at the relative water vapor pressure of ∼0.95. Similar dependence on hydration is also observed for several other anesthetics. The ratio of anesthetic partial pressures at which two different anesthetics reach the same fractional load is correlated with the anestheti...