Nanotech spy eyes life inside the cell
19:00 28 January 04

In Prey, Michael Crichton's tale of nanotech gone awry, a swarm of
light-sensitive nanoparticles swim through a human body, creating the
ultimate medical imaging system.

In the real world, biochemists are hoping to go one step further, deploying
viruses as "nano-cameras" to get a unique picture of what goes on inside
living cells and a greater understanding of how viruses themselves work.

A team led by Bogdan Dragnea at Indiana University in Bloomington is
exploiting the ability of viruses laden with gold to break into cells, along
with the viral shell's own telltale response to laser light. Together these
give an unprecedented picture of the chemical and physical activity in
cells.

Researchers currently study living cells using a technique called Raman
spectroscopy. When laser light bounces off some materials, most of the
scattered light has the same wavelength as the incident light. But a
fraction called the Raman spectrum has an altered wavelength due to the
characteristic vibration of some molecules in the material.

This allows researchers to map the coarser features of a cell, such as its
nucleus. But Raman spectra are very weak. Introducing gold nanoparticles
into cells enhances the Raman signal more than fivefold, because electrons
on the surface of the nanoparticle interact with and reinforce the scattered
light.

Unfortunately, the cell treats gold nanoparticles as foreign bodies and
quickly clears them out. But viruses are already able to avoid ejection. So
Dragnea and his team decided to use them as Trojan horses to smuggle the
particles into living cells.

Read the rest at New Scientist:
http://www.newscientist.com/news/news.jsp?id=ns99994615

Test-tube sperm get new genes
22:00 26 January 04

Growing sperm in a test tube may offer a powerful new way to genetically
modify animals and potentially correct human genetic diseases before
conception.

The technology offers two advantages. Firstly, it creates GM animals in one
generation rather than two, unlike most conventional techniques.

Secondly, because the genes are spliced into laboratory-born sperm, it may
allow scientists to do sophisticated genetic manipulations in a wide range
of animals. So far these have only been possible in mice.

"The big deal here is that this opens up vast possibilities to tailor this
technique for different applications," says Shawn Burgess of the US National
Institutes of Health in Bethesda, Maryland. But experts say the technology
will need to be improved further before it shows real promise.

http://www.newscientist.com/news/news.jsp?id=ns99994604

Posted by
Robert Karl Stonjek.
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