Influenza A virus (IFV-A) is one of the main cause of seasonal flu and can infect various of host species via the reassortment of segmented RNA genomes. Silver nanoparticles (AgNPs) have been known as excellent antiviral agent against IFV. However, the use of free AgNPs has several major drawbacks, including the inherent aggregation among AgNPs and unwanted cytotoxic or genotoxic damages for human body via inhalation or ingestion. In this study, we assessed the efficacy of our novel ~ 30-nm-diameter AgNP-decorated silica hybrid composite (Ag30-SiO; ~ 400 nm in diameter) for IFV-A inactivation. Ag30-SiO particles can inhibit IFV-A effectively in a clear dose-dependent manner. However, when real-time RT-PCR assay was used, merely 0.5-log reduction of IFV-A was observed at both 5 and 20 °C. Moreover, even after 1 h of exposure to Ag30-SiO particles, more than 80% of hemagglutinin (HA) damage and 20% of neuraminidase (NA) activities had occurred, and the infection of Madin-Darby Canine Kidney (MDCK) cells by IFV-A was reduced. The results suggested that the major antiviral mechanism of Ag30-SiO particles is the interaction with viral components located at the membrane. Therefore, Ag30-SiO particles can cause nonspecific damage to various IFV-A components and be used as an effective method for inactivating IFV-A.

No abstract

We report the original fabrication and performance of a photocurrent device that uses directly grown CdSe quantum dots (QDs) on a graphene basal plane. The direct junction between the QDs and graphene and the high quality of the graphene grown by chemical vapor deposition enables highly efficient electron transfer from the QDs to the graphene. Therefore, the hybrids show large photocurrent effects with a fast response time and shortened photoluminescence (PL) lifetime. The PL lifetime quenching can be explained as being due to the efficient electron transfer as evidenced by femtosecond transient absorption spectroscopy. These hybrids are expected to find applications in flexible electronics and optoelectronic devices.

Biomaterials derived via programmable supramolecular protein assembly provide a viable means of constructing precisely defined structures. Here, we present programmed superstructures of AuPt nanoparticles (NPs) on carbon nanotubes (CNTs) that exhibit distinct electrocatalytic activities with respect to the nanoparticle positions via rationally modulated peptide-mediated assembly. De novo designed peptides assemble into six-helix bundles along the CNT axis to form a suprahelical structure. Surface cysteine residues of the peptides create AuPt-specific nucleation site, which allow for precise positioning of NPs onto helical geometries, as confirmed by 3-D reconstruction using electron tomography. The electrocatalytic model system, i.e., AuPt for oxygen reduction, yields electrochemical response signals that reflect the controlled arrangement of NPs in the intended assemblies. Our design approach can be expanded to versatile fields to build sophisticated functional assemblies.

Mesoporous zirconia thin films (MZFs) were synthesized using zirconium hydroxide sol particles and a structure directing agent, Pluronic F127 (PEO106PPO70PEO106, EO = ethylene oxide, PO = propylene oxide). By controlling the F127/Zr ratio, we obtained two distinct MZFs with one in the Fmmm structure and the other in the P63/mmc structure. The pore structures of these films were characterized by low-angle X-ray diffraction, grazing incidence small-angle X-ray scattering, electron microscopy, and N2 sorption measurement. The Fmmm structure has interconnected pores and the P63/mmc structure has less accessible pores. The MZFs were functionalized with glucose oxidase (GOx) and were studied for their potentials as an electrochemical sensor for glucose. The GOx-functionalized MZF electrodes show high sensitivity to glucose in a broad range of glucose concentration of 0.025 - 6.8 mM, which can be attributed to their biocompatibility providing a favorable microenvironment for GOx immobilization and to their 3D pore structures with good accessibility of pores.