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25 June 2011 | NewScientist | 17 A steamy solution to drug delivery WATER gets weird when squeezed into tight spaces. Now a computer simulation of steam inside a carbon nanotube suggests these properties could be harnessed to deliver drugs. Ice-like structures have previously been seen inside nanotubes at temperatures far higher than 0 °C. The tight space means water molecules require more energy before they are able to move around enough to break free from each other and form a liquid. Now Oleg Prezhdo and Vitaly Chaban at the University of Rochester in New York have run a simulation of what happens to water when it is heated inside carbon nanotubes. This showed that it boiled at a higher temperature than normal, and when heated further the pressure of the steam increased faster than it would in a large container (ACS Nano, DOI: 10.1021/nn201277a). The researchers suggest using the rapid rise in pressure to “pop” open nanotube containers designed to smuggle drugs past the body’s defences. Infrared lasers could selectively heat the tubes from the outside, without harming the surrounding tissues, they say. Cancer cells betrayed by their sticky fractals MANDELBROT would have approved. As the founder of fractal geometry, he scoured nature for fractal patterns – and now they’ve been found on the surface of cervical cancer cells. Igor Sokolov’s team at Clarkson University in Potsdam, New York, used atomic force microscopy (AFM) to look for differences between healthy and cancerous cervical cells. The technique probes cells with tiny “fingers” to test their surface properties, such as strength and roughness. The group found that the surface of each cell was made up of regions of varying stickiness. After analysing four points on over 300 cells, they discovered that the patterns of stickiness on the cells had fractal properties – they repeated themselves when the microscope zoomed out. “We see a similarity in the patterns at 2 micrometres and 200 nanometres,” says Sokolov. Healthy cells were not fractal (Physical Review Letters, in press). Sokolov thinks the findings could be used to improve diagnosis. Currently, screening IT’S not just babies who like being rocked to sleep. Adults that are gently rocked fall asleep quicker and have a higher quality nap. So says Michel Mühlethaler at the University of Geneva, Switzerland, and colleagues who asked 10 men to take two 45-minute afternoon naps, one on a bed that rocked gently and one on a static bed. Patterns of brainwaves monitored by an EEG while they slept revealed that it took 4 minutes to fall asleep when being rocked, about 30 to 40 per cent less time than in a static bed. Rocking also helped the volunteers sleep more deeply; they spent 25 to 30 per cent longer in “N2” sleep, the deepest stage you reach in a nap (Current Biology, DOI: 10.1016/ j.cub.2011.05.012). The quality of N2 sleep improved too, as shown by a higher density of brain activity bursts called spindles. Spindle density is linked to memory improvement and insulation from noise disturbance. The team say rocking may help to synchronise sleep-related brainwaves in the hypothalamus and the cortex, possibly via input from the vestibular system in the inner ear, which monitors motion and balance. Rock-a-bye baby works for adults too PLAINPICTURE/BILDHUSET for cervical cancer involves manually identifying suspicious- looking cells. “The accuracy is barely over 50 per cent,” says Sokolov. The AFM method was able to identify cancerous cells in cervical swabs from 12 women with 100 per cent accuracy, he says. Nick Cole, a cancer researcher at the University of Cambridge, agrees that the results are encouraging, but stresses that the team must replicate their findings in precancerous cells – the ones that are usually picked up in screening tests. Red wine chemical unlocked at last FANCY receiving the heart protecting abilities of red wine without having to drink a glass every day? Soon you may be able to, thanks to the synthesis of chemicals derived from resveratrol, the molecule believed to give wine its protective powers. The chemicals have the potential to fight many diseases, including cancer. Plants make a huge variety of chemicals, called polyphenols, from resveratrol to protect themselves against invaders, particularly fungi. But they only make tiny amounts of each chemical, making it extremely difficult for scientists to isolate and utilise them. The unstable nature of resveratrol has also hindered attempts at building new compounds from the chemical itself. Scott Snyder at Columbia University in New York and his team have found a way around this: building polyphenols from compounds that resemble, but are subtly different to, resveratrol. These differences make the process much easier. Using these alternative starting materials, they have made dozens of natural polyphenols, including vaticanol C, which is known to kill cancer cells (Nature, DOI: 10.1038/nature10197). “It’s like a recipe book for the whole resveratrol family,” says Snyder. “We’ve opened up a whole casket of nature’s goodies.” PLAINPICTURE/ILUBI IMAGES For new stories every day, visit newscientist.com/news
