Friday, August 7, 2009

The engineers‘ dream of self-healing surfaces has taken another step towards becoming reality – researchers have produced a electroplated layer that contains tiny nanometer-sized capsules. If the layer is damaged, the capsules release fluid and repair the scratch.

The world's smallest computers, made of DNA and other biological molecules, just got more "user friendly" thanks to research at the Weizmann Institute of Science.

The world's smallest electric motor runs on only two atoms. The principle is easy: one starter and one motor atom in a ring of laser light - and a bit of fine tuning, in order to move always into the right direction.

Researchers at the University of Washington report progress in mapping brain tumors: theyhave been able to illuminate brain tumors by injecting fluorescent nanoparticles into the bloodstream that safely cross the blood-brain barrier – an almost impenetrable barrier that protects the brain from infection. The nanoparticles remained in mouse tumors for up to five days and did not show any evidence of damaging the blood-brain barrier.

Neurons communicate with each other with the help of nano-sized vesicles. Disruption of this communication process is responsible for many diseases and mental disorders like e.g. depression. Nerve signals travel from one neuron to another through vesicles - a nano-sized container loaded with neurotransmitter molecules. A vesicle fuses with the membrane surrounding a neuron, releases neurotransmitters into the surroundings that are detected by the next neuron in line. Researchers can now make "live recordings" of cell communication by quantifying contact areas formed between vesicles and determine the vesicle size and shape with nano-scale resolution.

evolutionary tree for nanoparticles

Researchers determine shape and size of the contact area between vesicle and membrane by measuring colour intensity from flourescent molecules. Right: Vesicle marked by acceptor flourescent molecules that light up when close to donor molecules (left). Middle: A plot of the same, calculated FRET.

The veil is being lifted from the once unseen world of molecular activity. Not so long ago only the final products were visible and scientists were forced to gauge the processes behind those products by ensemble averages of many molecules. The limitations of that approach have become clear with the advent of technologies that allow for the observation and manipulation of single molecules. A prime example is the recent first ever direct observations in real-time of the growth of single nanocrystals in solution, which revealed that much of what we thought we knew is wrong.

Scientists at the Technische Universitaet Muenchen and Harvard University have thrown the lid off a new toolbox for building nanoscale structures out of DNA, with complex twisting and curving shapes. They report a series of experiments in which they folded DNA, origami-like, into three-dimensional objects including a beach ball-shaped wireframe capsule just 50 nanometers in diameter. The result is a variety of nanoscale structures folded, origami-like, from DNA:

evolutionary tree for nanoparticles