11-06/07 :: June/July 2011

nanotimes News in Brief

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“Plasmonic coupling in multiple nanoparticles placed in proximity to each other leads to light scattering spectra that are sensitive to a complete set of 3D motions,” says Laura Na Liu, correspon- ding author of the Science paper. “The key to our success is that we were able to create sharp spectral features in the otherwise broad resonance profile of plasmon-coupled nanostructures by using interac- tions between quadrupolar and dipolar modes.”

In this animation of a 3D plasmon ruler, the plasmonic assembly acts as a transducer to deliver optical information about the structural dynamics of an attached protein. © Sven Hein, University of Stuttgart

Lab and leader of this research. “Two noble me- tallic nanoparticles in close proximity will couple with each other through their plasmon resonances to generate a light-scattering spectrum that depends strongly on the distance between the two nanopar- ticles,” Alivisatos says. “This light-scattering effect has been used to create linear plasmon rulers that have been used to measure nanoscale distances in biological cells.”

Compared to other types of molecular rulers, which are based on chemical dyes and fluorescence reso- nance energy transfer (FRET), plasmon rulers neither blink nor photobleach, and also offer exceptional photostability and brightness. However, until now plasmon rulers could only be used to measure distances along one dimension, a limitation that hampers any comprehensive understanding of all the biological and other soft-matter processes that take place in 3D.

http://www.pi4.uni-stuttgart.de

http://www.youtube.com/watch?feature=player_ embedded&v=dgdWrMaAxd4

Na Liu, Mario Hentschel, Thomas Weiss, A. Paul Alivisa- tos, Harald Giessen: Three-Dimensional Plasmon Rulers, In: Science, Vol. 332(2011), No. 6036, June 17, 2011: Pages 1407-1410, DOI: 10.1126/science.1199958: http://dx.doi.org/10.1126/science.1199958

CEA-Leti (Electronics and Information Techno- logy Laboratory of the French Atomic Energy Commission) were able to prove that the growth of ZnO nanowires by means of selective MOCVD Metal Organic Chemical Vapour Deposition over a silicon nitride mask is determinable. Electron beam lithography determines the mask‘s pattern. The nucleation efficiency of the wires is close to 100% and ensures exact control of size and position of