Highly ordered hexagonal arrays of parallel metallic nanowires (Ni, Bi) with diameters of about 50 nm and lengths up to 50 μm were synthesized by electrodeposition. Hexagonal-close-packed nanochannel anodized aluminum oxide film was used as the deposition template. The deposition was performed in an organic bath of dimethylsulfoxide with metal chloride as the electrolyte. A high degree of ordering and uniformity in these arrays can be obtained with this technique by fine-tuning the electrodeposition parameters. Moreover, an unprecedentedly high level of uniformity and control of the wire length was achieved. The arrays are unique platforms for explorations of collective behavior in coupled mesoscopic systems, and are useful for applications in high-density data storage, field emission displays, and sensors.

Gold nanostars offer unique plasmon properties that efficiently transduce photon energy into heat for photothermal therapy. Nanostars, with their small core size and multiple long thin branches, exhibit high absorption cross-sections that are tunable in the near-infrared region with relatively low scattering effect, making them efficient photothermal transducers. Here, we demonstrate particle tracking and photothermal ablation both in vitro and in vivo. Using SKBR3 breast cancer cells incubated with bare nanostars, we observed photothermal ablation within 5 minutes of irradiation (980-nm continuous-wave laser, 15 W/cm2). On a mouse injected systemically with PEGylated nanostars for 2 days, extravasation of nanostars was observed and localized photothermal ablation was demonstrated on a dorsal window chamber within 10 minutes of irradiation (785-nm continuous-wave laser, 1.1 W/cm2). These preliminary results of plasmon-enhanced localized hyperthermia are encouraging and have illustrated the potential of gold nanostars as efficient photothermal agents in cancer therapy.

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We study the magnetostatic interactions in planar arrays of single domain, magnetic disk nanostructures. We derive equations for the time evolution of magnetization and energy, and use these results to simulate the relaxation of these systems with a Monte-Carlo model. Our model confirms that relaxation of a one-dimensional array into one of its ground states occurs by propagating the inversion site along the line. A two-dimensional honeycomb array enters a metastable state of frustrated spiral domains due to the availability of low-energy configurational states. This model has potential application in the design of magnetic nanostructure systems for data storage and data processing applications.