Friday, June 4, 2010

This week in nanotechnology - June 4, 2010

In nano-optics breakthrough, researchers develop plasmonic amplifier. Under normal circumstances, optical energy travels over very short distances in plasmonic waveguides, before it is absorbed due to Ohmic loss in the metal. Although clever design can somewhat increase the useful length of plasmonic waveguides, it is widely accepted that the only way to completely overcome this problem is to add a mechanism that continuously amplifies the light as it travels along the plasmonic waveguide. However, integrating such plasmonic amplification has turned out to be a challenging task. developed a structure that provides sufficient amplification to overcome the intrinsic absorption of a plasmonic waveguide. In fact, the optical amplification is sufficient to provide a net gain of the plasmon-bound light as it travels along the waveguide.

When loaded with an anticancer drug, a delivery system based on a novel material called nanosponge is three to five times more effective at reducing tumor growth than direct injection. Imagine making tiny sponges that are about the size of a virus, filling them with a drug and attaching special chemical "linkers" that bond preferentially to a feature found only on the surface of tumor cells and then injecting them into the body. The tiny sponges circulate around the body until they encounter the surface of a tumor cell where they stick on the surface (or are sucked into the cell) and begin releasing their potent cargo in a controllable and predictable fashion.

nanosponges for drug delivery

The illustration shows a nanosponge particle attaching to human breast cancer cells. The particle holds an anticancer drug that it releases gradually as it decomposes. Peptide linkers are shown with the ball and stick representation. Although only two are shown in the illustration, about three dozen are attached to the surface of actual particles. The linkers are specially configured to bind to the surface of irradiated cancer cells.

Scientists have developed a new massively-parallel approach for manipulating single DNA and protein molecules and studying their interactions under force. The team of researchers claim that their technique, which they call "single molecule centrifugation", offers dramatic improvements in throughput and cost compared with more established techniques.

Chinese researchers have successfully built an electromagnetic absorbing device for microwave frequencies. The device, made of a thin cylinder comprising 60 concentric rings of metamaterials, is capable of absorbing microwave radiation, and has been compared to an astrophysical black hole (which, in space, soaks up matter and light).

Biorefinery concept shows a way out of a world dominated by petrochemicals. Advances in bio-based materials research show prospects that not only fuel but many other petrochemical derived products can be replaced with industrial materials processed from renewable resources. Researchers continue to make progress in research and development of new technologies that bring down the cost of processing plant matter into value-added products.

Self-propelled motion of synthetic materials can be useful in applications such as bottom-up assembly of structures, pattern formation, drug delivery at specific locations, etc. Researchers have now presented a novel and versatile light-driven catalytic micromotor system, which is the cleanest and simplest of its kind. In it, titanium dioxide is used to convert optical energy to mechanical energy via photocatalysis.

'Microfireworks': This video shows the photoactivity of a large titania particle in methanol. The surrounding tracer particles are silica