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Single nanotube experiment with tunable Ti:Sapphire laser Trestles sales@dmphotonics.com

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Published on Jan 18, 2010

Dmitri Tsyboulski performs single nanotube experiment with tunable Ti:Sapphire laser Trestles.

http://www.dmphotonics.com/Trestles-L...

More details on related research can be found on Professor Bruce Weisman website.
Dr. R. Bruce Weisman and his group investigate the spectroscopy and photophysics of fullerenes and carbon nanotubes. All of these are closed nanoscopic structures formed from carbon atoms. Fullerenes, such as C60, C70, and their chemical derivatives, have unusual molecular properties that cause interesting behaviors following the absorption of light. Time-resolved absorption and emission methods are used to study radiationless decay, photochemical reactions, and energy transfer in fullerenes. Another major research topic is single-walled carbon nanotube spectroscopy. Following the discovery in Weisman?s lab of near-infrared nanotube fluorescence, the group has measured and unraveled the absorption and emission spectra of more than 30 semiconducting nanotube species. Follow-up projects include detailed elucidation of nanotube electronic structure, as well as applications in non-invasive biomedical imaging and analytical nanotechnology.
Few publications and abstracts are cited below:

Laurent Cognet, Dmitri A. Tsyboulski, John-David R. Rocha, Condell D. Doyle, James M. Tour and R. Bruce Weisman "Stepwise Quenching of Exciton Fluorescence in Carbon Nanotubes by Single Molecule Reactions." Science, 316 (2007): 1465-1468.

Dmitry Tsyboulski, Ph.D. "Spectroscopic and Optical Imaging Studies of Fullerene Complexes and Single-Walled Carbon Nanotubes." (2006).(Thesis or Dissertation Director)

Multidomain Peptides as Single-Walled Carbon Nanotube
Surfactants in Cell Culture
We present a series of short, multidomain peptides as biocompatible solubilizing agents of single-walled carbon
nanotubes (SWCNTs). These peptides are organized into an ABA block motif, where the A block is composed
of charged amino acids, such as glutamic acid, and the B block is composed of alternating hydrophilic and
hydrophobic residues. The hydrophobic amino acid residues interact with SWCNT sidewalls, while the hydrophilic residues interact primarily with water in an aqueous solution. When many peptides assemble along the length of the nanotube, it becomes effectively encapsulated within a peptide nanofiber. This noncovalent interaction between the peptide and the nanotube solubilizes SWCNTs while keeping the electronic structure of the nanotube intact, thereby preserving the optical and electrical properties that make SWCNTs promising for use in biological applications. To assess the toxicity of these peptide coatings, they were added to cultures of NIH 3T3 mouse fibroblasts and the effect on cell viability was measured. Toxicity was found to be far lower than for ionic surfactants typically used for SWCNT suspension and similar to Pluronics. The near-IR fluorescence intensity of SWCNTs
in peptide suspensions was comparable to that in Pluronics. Five surfactants were tested for their effect on the proliferation of NIH 3T3 cells with and without SWCNTs. Although some differences were observed among surfactants, in no case did the presence of SWCNTs make a statistically significant difference. Based on their ability to solubilize SWCNTs, the fluorescence of the suspended tubes, their minimal impact on cell viability,
and their potential for easy chemical modification, multidomain peptides have been found to have excellent potential as a biocompatible surfactant for suspension of SWCNTs.Graphene is a one-atom-thick planar sheet of sp2-bonded carbon atoms that are densely packed in a honeycomb crystal lattice. The term Graphene was coined as a combination of graphite and the suffix -ene by Hanns-Peter Boehm, who described single-layer carbon foils in 1962. Graphene is most easily visualized as an atomic-scale chicken wire made of carbon atoms and their bonds. The crystalline or "flake" form of graphite consists of many graphene sheets stacked together.
The carbon-carbon bond length in graphene is about 0.142 nm. Graphene sheets stack to form graphite with an interplanar spacing of 0.335 nm, which means that a stack of 3 million sheets would be only one millimeter thick. Graphene is the basic structural element of some carbon allotropes including graphite, charcoal, carbon nanotubes, and fullerenes. It can also be considered as an indefinitely large aromatic molecule, the limiting case of the family of flat polycyclic aromatic hydrocarbons. The Nobel Prize in Physics for 2010 was awarded to Andre Geim and Konstantin Novoselov "for groundbreaking experiments regarding the two-dimensional material graphene".
Graphene is a flat monolayer of carbon atoms tightly packed into a two-dimensional (2D) honeycomb lattice, and is a basic building block for graphitic materials of all other dimensionalities. It can be wrapped up into 0D fullerenes, rolled into 1D nanotubes or stacked into 3D graphite.

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