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Surface plasmonics of nanomaterials has been one of the main research themes in nanoscience. Spherical and elongated nanoparticles show their corresponding unique optical features mainly depending on the physical dimensions. Here we successfully synthesized Au nanorings having Pt framework (Pt@Au nanorings) with high uniformity through wet-chemistry. The synthetic strategy consisted of serial reactions involving site-selective growth of Pt on the rim of Au nanoplates, subsequent etching of Au nanoplates, followed by regrowth of Au on the Pt rim. In this synthetic method, Au(3+) ions exhibited dual functionality as an etchant and a metal precursor. The resultant product, Pt@Au nanorings, exhibited unique localized surface plasmon resonance (LSPR) bands originating from the Au shell. The inner Pt skeleton turns out to be important to hold structural stability.

Herein, we report a general synthetic pathway to various shapes of three-dimensional (3D) gold nanoframes (NFs) embedded with a Pt skeleton for structural rigidity. The synthetic route comprises three steps: site-specific (edge and vertex) deposition of Pt, etching of inner Au, and regrowth of Au on the Pt framework. Site-specific reduction of Pt on Au nanoparticles (NPs) led to the high-quality of 3D Au NFs with good structural rigidity, which allowed the detailed characterization of the corresponding 3D metal NFs. The synthetic method described here will open new avenues toward many new kinds of 3D metal NFs.

The effects of beta-glucan isolated from Aureobasidium pullulans were observed on acute xylene-induced inflammation. beta-glucan at a dose of 62.5, 125 or 250 mg/kg were administered once orally to xylene-treated mice (0.03 mL of xylene was applied on the anterior surface of the right ear to induce inflammation), and the body weight change, ear weight, histological profiles and histomorphometrical analyses of ear were conducted upon sacrifice. The xylene was topically applied 30 min after dosing with beta-glucan. The results were compared to those of diclofenac, indomethacin and dexamethasone (15 mg/kg injected once intraperitoneally). All animals were sacrificed 2 h after xylene application. Xylene application resulted in marked increases in induced ear weights compared to that of intact control ear; hence, the differences between intact and induced ear were also significantly increased. The histological characteristics of acute inflammation, such as severe vasodilation, edematous changes of skin and infiltration of inflammatory cells, were detected in xylene-treated control ears with marked increase in the thickness of the ear tissues. However, these xylene-induced acute inflammatory changes were significantly and dose-dependently decreased by beta-glucan treatment. We conclude that beta-glucan from A. pullulans has a somewhat favorable effect in the reduction of the acute inflammatory responses induced by xylene application in mice.

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