Particle News Archives
A quantum dot IR laser made by dispersion
processing has recently been reported in Optics Express by a University of Toronto group
headed by Ted Sargent. These inventors developed thin film coating procedures to produce a smooth,
low-scattering-loss film inside the capillary, resulting in a whispering gallery mode laser
with a well-defined threshold. Performance surpasses previous attempts at colloidally-based lasing.
Proteolytic nanoparticle self-assembly
was recently described in an Angewandte Chemie International Edition paper by
Sangeeta Bhatia and co-workers, where sterically stabilized nanoparticles diffuse freely in biological fluids
until proteases expressed by cancer cells trigger them to self-assemble. Bhatia and co-workers
show that complimentary Fe3O4 nanoparticle binding is inhibited by the attachment of protease-cleavable
polymers. Cleavage of these polymers triggers “latent” nanoparticles to form multimeric assemblies with
Self-assembled nanoparticle superlattices are
demonstrated for binary lattices of the stiochiometries
AB, AB2, AB3, AB4, AB5, AB6, and AB13 in cubic, hexagonal, tetragonal, and orthorhombic symmetries
using monodisperse PbS, PbSe, CoPt3, Fe2O3, Au, Ag, and Pd nanocrystals in a soon to appear article
in the Journal of the American Chemical Society reported by Elena Shevchenko, Dmitiri Talapin, and Christopher Murray of IBM
and Stephen O'Brien of Columbia University.
Photonic devices from solution processed gold
nanoparticles were recently demonstrated by a collaboratoin between groups at the Cavendish Laboratory at
the University of Cambridge and the University of Bonn.
Engineered nanoceria particles protect healthy
cells during radiation exposure, but do not block cell death in tumor cells. This phenomenon
was recently reported in Nano Letters and demonstrated for a human breast tumor line, MCF-7 by Tarnuzzer,
Colon, Patil, and Seal of the University of Central Florida.
Conducting polymer nanotubes release drugs.
A group from the University of Michigan headed by David Martin reported recently
in Advanced Materials that nanotubes oxidatively synthesized from 3,4-ethylenedioxythiophene on gold
electrodes encased molecular drugs distributed in PLGA and then exuded their contents on demand when stimulated with an applied
Degussa European Science to Business Award
initiated by Degussa AG. Degussa, a global market leader in specialy chemicals and nanoparticles,
in partnership with Germany's leading business and financial newspaper Handelsblatt and one of Europe's leading business
schools, INSEAD, in France are co-sponsoring this €100,000 award to be made under the patronage of
the European science and research commissioner, Janez Potocnik. The first award, to be made in 2006,
will be for research in the field of material science and associated technologies. It is absolutely essential
that the work has a clear business potential.
IBM develops new nanotube-based transistor
that electroluminesces 1000-fold more brightly than do LED. The emitted infrared is obtained from
electrically stimulated exiton recombination in the nanotubes.
Nanosilica could eliminate foggy windows,
mirrors, and lenses Professor Rubner of MIT reported at the recent ACs meeting in Washington, DC a new approach to
coating with nanosilica particles. The basic idea is that the coated particles present a superhydrophilic surface, and water vapro, rather
than beading up, wets with very low contact angles, and essentially forms an ultrathin film.
Fluorescent CdTe nanocrystal-polymer
composites are reported in an upcoming article in Chemistry of Materials. Two effective routes are
reported. The first uses coating of the nanocrystals with a polymerizable surfactant, followed by
co-polymerization with styrene. The second route uses co-polymerization as a first step, followed by dispersion
of the nanocrystals.
Transparent and conducting carbon nanotube
sheets that are strong and self supporting are being fabricated by a process recently
reported in the Augsut 19th issue of Science by a group at the University of Texas at Dallas.
The generation of polymersomes from double
emulsions is reported in a soon to appear article in Langmuir. The use of block copolymers
to produce polymersomes was initially reported by the Discher group at the University of Pennsylvania.
These synthetic polymer-based vesicles have mechanical and physical properties superior to those obtained with
lipid-based vesicles. This upcoming communication from the Weitz group at Harvard demonstrates a double-emulsion
pathway to the precision synthesis of polymersomes using microfluidics.
A linear nanomotor powered by a metallic
nanocrystal ram sandwiched between carbon nanotube lever arms will appear shortly in Nano Letters.
This phenomenon is reported by a group from Berkeley. Low voltages drive atom transport from a nanocrystal
mass reservoir to the ram, whcih can be extended over a range of 0-150 nm at speeds up to 1900 nm/s.
Effects of urease enzyme structure on CaCO3
polymorph precipitation are reported in an upcoming report in Langmuir by Sondi and Salopek-Sondi of Croatia. The influcence of peptide
sequence is shown to affect the individual primary particle morphology as well as the overall microparticle
assembly. This report provides insight into the challenge of synthesizing nacre, which is 3000 tougher than
Multi-color LEDs from quantum dots
exhibiting one and two color electroluminescence has recently been reported by a group from Los Alamos National Laboraotry in
Nano Letters. The nanocrystals are encapsulated in GaN by a low temperature deposition technique.
Direct electron injection into the quantum dots at 1% efficiency results in one or two-color electroluminescence from nanocrystal
monolayers or bilayers, respectively, incororated into p-n junctions formed from GaN injection layers.
Super-liquid-repellant surfaces prepared from
colloidal silica and perfluorinated silanizing agents has recently been reported in Langmuir.
The Kajiyama and Takahara groups from the Japan Chemical Innovation Institute and Kyushu University, respectively, report
a novel approach to formulating liquid repellant coatings.
A new route to fcc and fct FePt nanoparticles
will soon appear in the Journal of the American Chemical Society. A group at the University of Durham
describe the size-controlled synthesis of FePt nanoparticles, important for terabit/cm/cm magnetic data storage potential, in the fcc structure
and the transformation to fct without significant particle sintering.
Bonding technology in cars: Nanoparticle-based adhesives instead of screws, rivets and
welding adhesives are increasingly used in modern automotive production. They allow different
materials to be permanently bonded in an energy-efficient manner and without the need for other auxiliary parts.
The specialty chemicals company Degussa AG of Dusseldorf, Germany supplies materials that are used in innovative bonding technology
to design vehicles for the future that will be safer and more economical.
Metal decorated nanotubes hold promise for fuel cells
NIST theorist Taner Yildirim and phsyicist Salim Ciraci of Turkey's Bilkent University report in online Physical Review Letters their "unanticipated findings
that hydrogen can reversibley amass in amounts equivalent to 8% of the weight of titanium-decorated single walled carbon nanotubes. THis is 33% better than the 6%
minimum storage-capacity requirement set by the FreedomCar Research Partnership involving the DOE and the "Big 3" automakers.
Nanoparticles: An occupational hygiene review
Hundreds of nanoparticle applications are in production despite a huge health and safety question mark. This review
focuses on world and UK situations.
Study finds advantages to environmental cleanup with iron nanoparticles
Some iron nanoparticles may be effective in cleaning up carbon tetrachloride
in contaminated groundwater.
A biomagnetic system for in vivo cancer imaging
Ed Flynn and Howard Bryant in a recent Physics in Medicine and Biology paper report the implementation
of in vivo detection using antibody-labelled magnetic nanoparticles using a weak field magnetic sensor SQUID system.
New route to nanoparticle metal oxides from condensed phase
Nicola Pinna, Georg Garnweitner, Markus Antonietti, and Markus Niederberger of the Max Planck
Institute for Colloids in Golm recently reported a novel approach to producing nanocrystalline metal oxide nanoparticles
from the condensed state. This new solvolysis approach does not rely on water; metal acetylacetonates undergo
solvolysis with carbon-carbon bond cleavage in ketimine and aldol-like condensation steps.
Viral templating of monodisperse dielectric shells
Corey Radloff and Richard Vaia of the Air Force Research Laboratory report in an upcoming issue of
Nano Letters that viral capsids can be used to template monodisperse dielectric shells, by initially adsorbing gold nanoparticles,
and by then using these particles to catalyze gold film formation.
Chemically modified opals as thin permselective membranes
A group from the University of Utah report in a soon to be published communication in the
Journal of the American Chemical Society that thin layer opal structures constructed from fcc arrangements
of monodisperse particles on electrodes, when surface functionalized, can be used to block unwanted redox species while
interogating desired species at the underlying electrode.
Thanks to the 220+ conferees who made Particles 2005 such a rich and stimulating conference!