| |
DNA nanorobots can target cancer cells and deliver an antibody payload (purple). Image: Nature
|
|
Issue no. 5, 2012
Published: Feb 17, 2012 |
|
 DNA robot kills cancer cells | | New malaria method could boost drug production | | Scientists teach computers to assess psychiatric risk | | Study raises questions over nano impact | | LEDs that burn 10 times brighter | | 'Invisibility cloak' could hide buildings from earthquakes | | Swiss aim to launch first space cleaner | | Rapunzel number helps scientists quantify ponytails |
|
| DNA robot kills cancer cells |
DNA origami, a technique for making structures from DNA, can be used to
build devices that can seek out and destroy living cells. The nanorobots
use a similar system to cells in the immune system to engage with
receptors on the outside of cells. Once the device recognizes a cell it
automatically changes its shape and delivers its cargo.
Researchers at Harvard Medical School in Boston, Massachusetts, designed
the structure of the nanorobots using open-source software, called
Cadnano. They then built the bots using DNA origami. The barrel-shaped
devices, each about 35 nm in diameter, contain 12 sites on the inside
for attaching payload molecules and two positions on the outside for
attaching aptamers, short nucleotide strands with special sequences for
recognizing molecules on the target cell. The aptamers act as clasps:
once both have found their target, they spring open the device to
release the payload.
The researchers tested six combinations of aptamer locks, each of which
were designed to target different types of cancer cells in culture.
Those designed to hit a leukaemia cell could pick that cell out of a
mixture of cell types then release their payload - in this case, an
antibody - to stop the cells from growing. They also tested payloads
that could activate the immune system.
Whether or not these structures will work in a living organism remains
to be seen. For one thing, they are designed to communicate with
molecules on a cell's surface. What's more, the nanorobots are quickly
cleared by the liver or destroyed by nucleases, enzymes chew up stray
bits of DNA. |
| Nature
Feb 16, 2012 |
 back to top
|
|
| New malaria method could boost drug production |
German scientists have developed a new way to make a key malaria drug
that they say could easily quadruple production and drop the price
significantly, increasing the availability of treatment.
Chemists at the Max Planck Institute take the waste product from the
creation of the drug artemisinin - artemisinic acid - and convert it
into the drug itself. The entire apparatus is compact, about the size of
a carry-on suitcase, and inexpensive. That means it can be easily added
to production sites anywhere around the world.
Artemisinin is extracted from sweet wormwood, a plant that primarily
grows in China and Vietnam and varies in its availability according to
the season. In the extraction process, for every part artemisinin
produced, there is 10 times the amount of artemisinic acid discarded as
waste. Past attempts to convert the acid using ultraviolet light to
trigger the conversion have been unsuccessful because the process took
several steps in a large tank of acid, making production inefficient and
far too expensive.
So the Max Planck chemists thought small - creating a machine that pumps
all of the required ingredients through a thin tube wrapped around a UV
lamp in a continuous process that takes 4.5 minutes from start-to-finish
to produce the artemisinin. The technique can convert about 40% of the
waste acid into artemisinin - producing four times more of the drug from
what had in the past been discarded. |
| Yahoo! / AP / Angewandte Chemie
Feb 16, 2012 |
back to top
|
|
| Scientists teach computers to assess psychiatric risk |
Computer programs can be taught to select between brain scans of healthy
young people and scans showing adolescents who are at higher risk of
developing mental disorders such as anxiety and depression. Researchers
at the University College London said it may be possible to design
programs to predict which at-risk adolescents will go on to have
psychiatric problems, giving doctors more time to intervene.
Depression and other psychiatric disorders are a major cause of death,
disability and economic burden worldwide. The World Health Organization
predicts that by 2020, depression alone will be the second leading
contributor to the global burden of disease across all ages. Two studies
published late last year found that up to 40% of Europeans suffer from
mental and neurological illnesses each year, and the annual cost of
brain disorders is almost EUR 800bn.
But experts think that being able to diagnose potential problems
earlier, and intervene to help at-risk young people, could significantly
reduce the damage caused by psychiatric disorders and help ward off
serious or recurrent illness. As yet there are no known biological
measures, or biomarkers, that can predict future psychiatric disorders.
The University College team took 16 healthy adolescents who each had a
parent with bipolar disorder, and 16 whose parents had no history of
psychiatric illness, and scanned their brains with a fMRI scanner while
they performed a specially designed emotional test. The researchers then
used software capable of machine learning to predict the probability
that an individual belonged to either the low-risk or at-risk group and
found it was accurate in three out of four cases. The team also found
the program predicted significantly higher risk probabilities for young
people who were found in follow-up to have developed psychiatric
disorders than for those who remained healthy at follow-up. |
| Reuters / PLoS ONE
Feb 15, 2012 |
back to top
|
|
| Study raises questions over nano impact |
Tests involving chickens have raised questions about the impact on
health from engineered nano-particles, the ultra-fine grains commonly
used in drugs and processed foods.
Chickens exposed to high oral doses of polystyrene particles 50nm across
absorbed less iron in their diet, according to the new study by
researchers at Cornell University in New York. At the same time, birds
that were chronically exposed to these doses had a 'remodelling' of
their intestinal villi, the microscopic finger-like projections that
play an important role in absorbing nutrients. The changes meant that
the villi increased the surface area available for taking in iron.
Intestinal uptake of calcium, copper, zinc and vitamins A, D, E and K
may also be affected by high exposure to nanoparticles, although further
research is needed to investigate this, say the authors.
The team tested the particles on chickens as a substitute for the human
intestine and also used lab-dish cells from the lining of the human gut.
The chickens were given roughly the same dose, weight for weight, as an
adult human in a developed country.
Engineered nanoparticles are used increasingly in the form of titanium
oxide or as aluminium silicates in pills to help deliver medication and
in food, where they are used as stabilisers or anti-caking agents in
fluids and creams. In developed countries, individuals may be consuming
each day a thousand billion engineered particles ranging from fine to
ultrafine in scale, according to figures from 2002 research. |
| ABC New / AFP
Feb 13, 2012 |
back to top
|
|
| LEDs that burn 10 times brighter |
LED lightbulbs promise a highly efficient, nontoxic, long-lasting
alternative to today's incandescent and halogen lightbulbs. Lighting
entire rooms using LEDs has, however, proved both technically
challenging and expensive.
Soraa, a California based startup, has developed a new type of LED that
generates 10 times more light from the same quantity of active material
used in other LEDs. The company's first product is a 12-watt bulb that
uses 75% less energy than a similarly illuminating 50-watt halogen bulb.
The company would not disclose the cost of the bulb, but says it will
pay for itself in less than one year through energy savings.
LEDs contain a semiconducting material that lights up when current
passes through it. LEDs are usually made by growing a thin layer of
gallium nitride on top of a sapphire, silicon carbide, or silicon
substrate. Soraa takes a different approach. It uses gallium nitride for
the substrate. This reduces a mismatch in the crystal structure between
the two layers, which causes the performance of LEDs to diminish as
current densities increase. By reducing such mismatches, or
'dislocations', by a factor of 1,000, Soraa says they can push 10 times
more current through a given area of active layer material. The increase
in current density results in a tenfold increase in LED brightness.
Gallium nitride is significantly more expensive than either sapphire or
silicon-based materials, but the increased output more than makes up for
the added cost, says Soraa. |
| Technology Review
Feb 13, 2012 |
back to top
|
|
| 'Invisibility cloak' could hide buildings from earthquakes |
A team of British mathematicians at the University of Manchester has
developed a theoretical design for a 'cloaking' device which could
protect buildings from earthquakes.
Over the last year or so, scientists have come up with a number of
cloaking devices working in different contexts. Now the University of
Manchester team says it is possible to use the same techniques to
protect buildings and structures from vibrations and natural disasters
such as earthquakes.
By cloaking components of structures with pressurised rubber powerful
waves such as those produced by an earthquake would not 'see' the
building - they would simply pass around the structure and thus prevent
serious damage or destruction. The building, or important components
within it, could theoretically be 'cloaked'.
This invisibility could prove to be of great significance in
safeguarding key structures such as nuclear power plants, electric
pylons and government offices from destruction from natural or terrorist
attacks. |
| TG Daily
Feb 15, 2012 |
back to top
|
|
| Swiss aim to launch first space cleaner |
Swiss scientists plan to develop a machine that acts almost like a
vacuum cleaner to scoop up thousands of abandoned satellite and rocket
parts, cleaning up outer space.
The Swiss Space Centre at the Ecole Polytechnique Federale de Lausanne
(EPFL) announced the launch of CleanSpace as the first instalment of a
family of satellites designed to clear up space debris.
According to EPFL, 16,000 objects larger than 10 centimetres in diameter
and hundreds of millions of smaller particles are ripping around the
earth at speeds of several kilometres per second.
EPFL said two options are being considered for the cleaning satellites.
One is a machine that scoops up debris and then burns itself up in
Earth's atmosphere. The second is a model capable of retrieving the
debris, which is then ejected into the atmosphere while the cleaner
remains in space.
According to a 2011 study by Swiss Re insurance company there is a
nearly one in 10,000 chance that an orbiting satellite measuring 10
square metres will collide with a piece of space debris larger than one
centimetre every year. |
| Yahoo! / AFP
Feb 16, 2012 |
back to top
|
|
| Rapunzel number helps scientists quantify ponytails |
Scientists from the University of Cambridge and the University of
Warwick say that a 'Rapunzel Number' may have helped them to crack a
problem that has perplexed humanity since Leonardo da Vinci pondered it
500 years ago.
The team said they had devised a 'Ponytail Shape Equation', which when
calculated using the Rapunzel Number and a measure of the curliness of
hair can be used to predict the shape of any ponytail. The researchers
took account of the stiffness of individual hairs, the effects of
gravity and the average waviness of human hair to come up with their
formula.
The Rapunzel Number provides a key ratio needed to calculate the effects
of gravity on hair relative to its length. That determines whether the
ponytail looks like a fan or whether it arcs over and becomes nearly
vertical at the bottom, the researchers say. The research also took into
account how a bundle of hair is swelled by the outward pressure which
arises from collisions between the component hairs.
Scientists said the work has implications for understanding the
structure of materials made up of random fibres, such as wool and fur
and will have resonance with the computer graphics and animation
industry, where the representation of hair has been a challenging
problem. |
| Reuters
Feb 10, 2012 |
back to top
|
|
|
