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PROFESSOR STEVE P. ARMES
The PhysOrg article
Making Better Magnetic Nanoparticles said
Using a polymer coating designed to resemble the outer surface of a
cell membrane, a team of investigators led by Steve Armes, Ph.D., of the
University of Sheffield in the United Kingdom, has created a highly
stable, biocompatible magnetic nanoparticle expected to improve the
sensitivity of magnetic resonance imaging (MRI). This work is reported
in the journal Langmuir.
The investigators first created the polymer by joining two polymers that
each have constituents found on the surface of cell membranes. They then
added this polymer to the standard chemical reaction mixture used to
produce iron oxide nanoparticles. The resulting particles have an
average diameter of approximately 34 nanometers, with the iron oxide
core having an average diameter of 9 nanometers and a range of 6 to 14
nanometers.
In comparison, iron oxide nanoparticles prepared without the coating had
an average diameter of 13 nanometers and a range of 9 to 21 nanometers.
The magnetic properties of the stabilized nanoparticles were similar to
those of standard iron oxide nanoparticles.
Steve P. Armes, Ph.D. is Professor of Chemistry, The University of
Sheffield, UK.
His research interests include:
Polymer Chemistry. He uses living radical polymerization
techniques
such
as Atom Transfer Radical Polymerization (ATRP) to synthesize a wide
range of controlled-structure, methacrylate-based water-soluble
polymers. Block copolymers and their micellar self-assembly in aqueous
solution are a particular interest: he was the first to discover
"schizophrenic" AB diblock copolymers that can form two types of
micelles (either the "A" block in the core or the "B" block in the
core)
in aqueous solution.
His most recent work provides the first
example of
a "trinity" of such micelles formed by an ABC triblock copolymer. He
pioneered the use of related ABC triblock copolymers for the synthesis
of shell cross-linked micelles at high solids. Thermo-responsive
biocompatible gelators and pH-responsive "stealth" micelles have been
produced by preparing ABA and AB diblock copolymer architectures based
on a biomimetic monomer, 2-methacryloyloxyethyl phosphorylcholine (MPC).
The design of zwitterionic diblock copolymers to produce
stimulus-responsive surface-adsorbed micelles is also of interest.
Colloid Chemistry. He prepares a broad range of microscopic
conducting
polymer-based particles, including conducting polymer-coated latexes,
conducting polymer-silica nanocomposite particles, and sterically
stabilized conducting polymer particles. Such particles are interesting
synthetic mimics for carbonaceous and silicate-based micro-meteorites,
which has implications for Cassini (an unmanned spacecraft currently
orbiting Saturn).
He uses ultrafine aqueous silica sols to
prepare a
range of vinyl polymer-silica nanocomposite particles. Film-forming
nanocomposite compositions can be prepared using acrylic monomers, which
have some potential as tough, transparent, scratch-resistant coatings.
Other recent examples include the synthesis of novel
sterically-stabilized pH-responsive microgels, surface polymerization
from ultrafine silica sols in aqueous solution, and the evaluation of
various latexes, microgels, and nanocomposites as "Pickering"
emulsifiers
for the production of oil-in-water emulsions.
Steve coauthored
A schizophrenic water-soluble diblock copolymer,
Micellization in pH-sensitive amphiphilic block copolymers in aqueous
media and the formation of metal nanoparticles,
Stimulus-responsive liquid marbles,
Self-assembled block copolymer aggregates: from micelles to vesicles
and
their biological applications, and
Synthesis of model primary amine-based branched copolymers by
pseudo-living radical copolymerization and post-polymerization coupling
of homopolymers.
Read the
full list of his publications!
Steve earned his BSc at the University of Bristol, UK in 1983 and his
Ph.D. at the University of Bristol, UK in 1987). He did his
postdoctoral work at the Los Alamos National Laboratory, New Mexico, USA
from 1987 to 1989.
He was awarded the Royal Society of Chemistry's Macro Group Medal in
2007.
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