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 20:00 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.