12-01 :: January 2012
nanotimes News in Brief
Zubarev and his co-workers have now developed a new strategy that solves these problems: they replaced the CTAB with a variant that contains a sulfur-hydrogen group, abbreviated as MTAB. With various analytical processes, the scientists have been able to prove that the CTAB on these nanorods is completely replaced with an MTAB layer. The MTAB molecules chemically bond to gold nanorods through their sulfur atoms. They bind so tightly that the layer stays in place even in an aqueous solution and the rods can even be freeze-dried. They can be stored indefinitely as a brown powder and dissolve in water again within seconds.
Tests on cell cultures demonstrate that MTAB gold nanorods are not toxic, even at higher concen- trations. In addition, they are absorbed in large amounts by tumor cells. The scientists estimate that under the conditions of their experiment, a single cell takes up more than two million nanorods. This would make effective photothermal tumor treat- ment possible.
Leonid Vigderman, Dr. Pramit Manna, Prof. Eugene R. Zubarev: Quantitative Replacement of Cetyl Trimethyl- ammonium Bromide by Cationic Thiol Ligands on the Surface of Gold Nanorods and Their Extremely Large Uptake by Cancer Cells, In: Angewandte Chemie Inter- national Edition, Volume 51, Issue 3, Pages 636-641, Ja- nuary 16, 2012, DOI:10.1002/anie.201107304:
http://dx.doi.org/10.1002/anie.201107304
http://www.owlnet.rice.edu/~zubarev/
group.htm
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Engineers at Stanford University have created pho- tovoltaic nanoshells that harness a peculiar phy- sical phenomenon to better trap light in the solar materials. The results could dramatically improve the efficiency of thin-film solar cells while reducing their weight and cost.
“The solar film in our paper is made of rela- tively abun- dant silicon, but down the road, the reduction in materials afforded by nanoshells could prove important to scaling up the manufacturing of many types of thin film cells, such as those which use rarer materials like tellurium and indium” said Vijay Narasimhan, a doctoral candidate in the Cui Lab and co-author of the paper.
Image: A scanning electron microscope (SEM) image of a single layer of nanocrystalline-silicon shells. The hollow shell structure improves light absorption while reducing the cost and weight of the device. © Yan Yao
Yan Yao, Jie Yao, Vijay Kris Narasimhan, Zhichao Ruan, Chong Xie, Shanhui Fan, Yi Cui: Broadband light manage- ment using low-Q whispering gallery modes in spherical nanoshells, In: Nature Communications, Vol. 3(2012), February 2012, Article number: 664. DOI:10.1038/ ncomms1664:
http://dx.doi.org/10.1038/ncomms1664 https://engineering.stanford.edu
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