Friday, November 20, 2009

This week in nanotechnology, Nov.20, 2009

Lots of nanomedicine and nanobiotechnology this week! Let's start with cancer medicine: A team of researchers on the cutting edge of nanomedicine has found a way to capture tumor cells in the bloodstream that could dramatically improve earlier cancer diagnosis and prevent deadly metastasis. The way this works is that the scientists can inject a cocktail of magnetic and gold nanoparticles with a special biological coating into the bloodstream to target circulating tumor cells. A magnet attached to the skin above peripheral blood vessels can then capture the cells.

Research with a similar goal was carried out at UCLA. Just as fly paper captures insects, an innovative new device with nanosized features is able to grab cancer cells in the blood that have broken off from a tumor. Their nanopillar chip captured more than 10 times the amount of cells captured by the currently used flat structure.

Quite a number of serious medical conditions, such as cancer, diabetes and chronic pain, require medications that cannot be taken orally, but must be dosed intermittently, on an as-needed basis, and over a long period of time. Researchers have been trying to develop drug delivery techniques with 'on-off switches' that would allow controlled release of drugs into the body. By combining magnetism with nanotechnology, researchers have now created a small implantable device that encapsulates the drug in a specially engineered membrane, embedded with magnetic iron oxide nanoparticles.

The atomic-level action of a remarkable class of ring-shaped protein motors has been uncovered by researchers at Berkeley Lab using a state-of-the-art protein crystallography beamline at the Advanced Light Source. These protein motors play pivotal roles in gene expression and replication, and are vital to the survival of all biological cells, as well as infectious agents, such as the human papillomavirus, which has been linked to cervical cancer.

The genetic material found in cells is not in its free state, but is bound to large protein complexes and tightly wrapped. To activate genes that could well play a role in carcinogenesis, the genetic material first needs to be unwrapped and made accessible to other cell components. Using a new biophysical method called single molecule spectroscopy, scientists in Germany were the first to directly observe these mechanisms and characterise the intermediate stages leading to free genetic material.

Existing solid-state devices to convert heat into electricity are not very efficient. Researchers have been trying to find how close realistic technology could come to achieving the theoretical limits for the efficiency of such conversion. In everything from computer processor chips to car engines to electric powerplants, the need to get rid of excess heat creates a major source of inefficiency. But new research points the way to a technology that might make it possible to harvest much of that wasted heat and turn it into usable electricity.

The University of Ghent and the nanoelectronics research center IMEC demonstrated repulsive and attractive nanophotonic forces, depending on the spatial distribution of the light used. These fundamental research results might have major consequences for telecommunication and optical signal processing.

With a bit of leverage, Cornell researchers have used a very tiny beam of light with as little as 1 milliwatt of power to move a silicon structure up to 12 nanometers. That's enough to completely switch the optical properties of the structure from opaque to transparent, they reported. The technology could have applications in the design of micro-electromechanical systems (MEMS) – nanoscale devices with moving parts – and micro-optomechanical systems (MOMS) which combine moving parts with photonic circuits.

Scanning electron micrograph of two thin, flat rings of silicon nitride, each 190 nanometers thick and mounted a millionth of a meter apart


Scanning electron micrograph of two thin, flat rings of silicon nitride, each 190 nanometers thick and mounted a millionth of a meter apart. Light is fed into the ring resonators from the straight waveguide at the right. Under the right conditions optical forces between the two rings are enough to bend the thin spokes and pull the rings toward one another, changing their resonances enough to act as an optical switch.