BBC Knowledge Asia Edition2

MEDICINE

Update

THE LATEST INTELLIGENCE

Tiny light-activated semiconductors could be used in the fight

against infections such as E. coli and salmonella

QUANTUM DOTS TO COMBAT

PROTECTION DRUG-RESISTANT BACTERIA

ENCOURAGES

RECKLESSNESS

Recent research suggests

safety kit may increase the

urge to take risks. Volunteers

at the University of Bath were

asked to inflate a virtual

balloon as much as possible

without bursting it. Some were

given a cycling helmet to wear

during the task; those that

did were more likely to fill the

balloon for longer.

OPACITY IS NO

GUIDE TO DENSITY

Data from NASA’s Cassini

mission shows that although

the opacity of Saturn’s B ring

varies, the amount of material

it contains is almost

uniform throughout.

VENUS FLYTRAPS

CAN COUNT

Researchers at Germany’s

Universität Würzburg mimicked

an insect landing on the

carnivorous plants and were

able to show that one touch

didn’t trigger the trap. Only

after a second touch would the

plant close its jaws around the

insect.

MOON LANDING

FAKE IN FOUR

YEARS

According to Dr David Grimes of

Oxford University, the number of

people required to fake the first

Moon landing would mean the

plot would have been exposed

within four years.

WHAT WE LEARNED

THIS MONTH

PHOTOS: GETTY, SCIENCE PHOTO LIBRARY, WIKIPEDIA

Salmonella bacteria (red)

can cause severe fever, vomiting

and diarrhoea

Quantum dots – tiny flecks of

semiconducting materials that react to light

• may solve the growing problem of drug-
  resistant bacteria, according to researchers
  at the University of Colorado Boulder.
  Infections such as E. coli, staphylococcus
  and salmonella, which are contracted by two
  million people each year, are becoming
  harder to treat. This is because the bacteria
  that cause them are adapting to become
  immune to antibiotic drugs.
  The scientists, based at the Department of
  Chemical and Biological Engineering, have
  managed to create light-activated
  therapeutic nanoparticles – quantum dots
  
  
  • that are able to destroy 92 per cent of drug-
    resistant bacteria in experiments. The
    quantum dots are made from the
    semiconductor cadmium telluride – a
    material that can conduct electricity under
    certain conditions – and are 20,000 times
    smaller than the width of a human hair. The
    dots are activated by light, which triggers a
    chemical reaction to break down the
    bacteria. And as the quantum dots are so
    small, they can be easily absorbed by the
    invading bacteria.
    “By shrinking these semiconductors
    down to the nanoscale, we’re able to create
    highly specific interactions within the cellular
    environment that only target the infection,” said
    Prashant Nagpal, a senior author of the study.
    There have been attempts at using
    nanoparticles made from metals, including
    gold and silver, to fight drug-resistant
    bacteria, but these were found to damage
    the cells surrounding the bacteria
    indiscriminately. The semiconductor
    quantum dots, however, target the
    bacteria specifically.
    More importantly, the quantum dots
    can be altered so that they remain effective
    even if the bacteria adapts to this form
    of treatment.