10-04 :: April 2010

nanotimes

News in Brief

damage to tissue being imaged. Another advantage is that it does not produce a background „auto fluorescent“ glow of surrounding tissues, which interferes with the imaging and reduces contrast and brightness, said Ji-Xin Cheng (pronounced Gee-Shin), an associate professor of biomedical engineering and chemistry at Purdue University.

“This lack of background fluorescence makes the images much more clear and is very important for disease detection,” he said. “It allows us to clearly identify the nanocages and the tissues.” The gold-silver structures yielded images 10 times brighter than other experimental imaging research using gold nanospheres and nanorods. The ima- ging technology provides brightness and contrast potentially hundreds of times better than conven- tional fluorescent dyes used for a wide range of biological imaging to study the inner workings of cells and molecules.

Ling Tong, Claire M. Cobley, Jingyi Chen, Younan Xia, Ji- Xin Cheng: Bright Three-Photon Luminescence from Gold/ Silver Alloyed Nanostructures for Bioimaging with Negli- gible Photothermal Toxicity (p NA), In: Angewandte Che-

mie International Edition, Early View, April 6 2010, DOI:

10.1002/anie.201000440: http://dx.doi.org/10.1002/anie.201000440

Ji-Xin Cheng:

https://engineering.purdue.edu/BME/Research/Labs/Cheng

Weldon School of Biomedical Engineering:

http://www.purdue.edu/bme

Younan Xia:

http://engineering.wustl.edu/facultybio.aspx?faculty=137

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This composite image shows luminous nanocages, which appear like stars against a black background, and a living cell, at upper left. The gold-silver nanocages exhibit a bright „three-photon luminescence“ when excited by the ultrafast pulsed laser, with 10-times greater intensity than pure gold or silver nanoparticles. The signal allows live cell imaging with negligible damage from heating. © Purdue University graphic/Ji-Xin Cheng

Physicists at Harvard University, USA, have found

that a high-voltage nanotube can cause cold atoms to spiral inward under dramatic accelera- tion before disintegrating violently. Their expe-

riments, the first to demonstrate something akin to a black hole at atomic scale, are described in the current issue of the journal Physical Review Letters. “On a scale of nanometers, we create an inexo- rable and destructive pull similar to what black holes exert on matter at cosmic scales,” says Lene Vestergaard Hau, Mallinckrodt Professor of Physics