X-Message-Number: 31319
Date: Sun, 4 Jan 2009 10:50:40 -0800 (PST)
From: 
Subject: Anti-glycation activity of gold nanoparticles

[Gold nanoparticles appear to be unusually effective at inhibiting
glycation. Since the larger sized nanoparticles are regarded as
completely? safe, then perhaps these may prove to be an effective therapy
for cataracts, as well as possibly presbyopia and some other diseases of
aging.]

Snip: "Formation of advanced glycosylic end products is prevented even if a
strong glycating agent such as fructose is used"

Nanomedicine. 2008 Jul 25. [Epub ahead of print]
Anti-glycation activity of gold nanoparticles.
  Singha S, Bhattacharya J, Datta H, Dasgupta AK. Department of
Biochemistry, Calcutta University, Kolkata, India.
  Anti-glycation activity of gold nanoparticles (GNPs) has been reported for
the first time. Nonenzymatic glycation of alpha-crystallin leads to
formation of cataract, or opaque aggregate of proteins. In this article we
report prevention of glycation of alpha-crystallin by conjugation with GNPs.
Formation of advanced glycosylic end products is prevented even if a strong
glycating agent such as fructose is used. In addition, the nanoconjugation
can provide some important information on the structural distribution of
this dynamic chaperone protein. Because GNPs are biocompatible, their
reported anti-glycation activity may have ophthalmological implications.
PMID: 18676206

Snip: "significantly larger gold nanoparticles are completely non-toxic"

Chem Soc Rev. 2008 Sep;37(9):1909-30. Epub 2008 Jul 2.
The relevance of shape and size of Au55 clusters.
  Schmid G. Universitat Duisburg-Essen, Institut fur Anorganische Chemie,
Universitatsstrasse 5-7, Essen, 45117, Germany.
  This critical review deals with the history of Au55(PPh3)12Cl6 and its
derivatives from the very beginning in 1981 to date. Au55 clusters obtain
their special interest from their ultimate size and their ideal
cuboctahedral structure. They are part of the family of so-called full-shell
clusters, particles with perfectly completed geometries, also represented by
icosahedral Au13 clusters. Bare as well as ligand protected Au55 clusters
not only exhibit special chemical and physical stability, but draw their
attention particularly from their unique electronic properties. Single
electron switching at room temperature becomes possible, giving rise for
development of applications in future nanoelectronic devices. A
predominantly size-determined property of the 1.4 nm particles becomes
obvious with respect of biological response. Au55 clusters indicate an
unusual cytotoxicity which seems to be caused by the unusually strong
interaction between the 1.4 nm particles and the major grooves of DNA. Only
marginally smaller or larger particles show drastically reduced toxicity,
whereas significantly larger gold nanoparticles are completely non-toxic.
Both, the electronic perspectives as well as the relevance in toxicology are
at very early stages of development (75 references).
PMID: 18762839

Acc Chem Res. 2008 Aug 20. [Epub ahead of print]
Gold Nanoparticles in Biology: Beyond Toxicity to Cellular Imaging.
  Murphy CJ, Gole AM, Stone JW, Sisco PN, Alkilany AM, Goldsmith EC, Baxter
SC. dagger Department of Chemistry and Biochemistry, University of South
Carolina, Columbia, South Carolina 29208 .
  Gold, enigmatically represented by the target-like design of its ancient
alchemical symbol, has been considered a mystical material of great value
for centuries. Nanoscale particles of gold now command a great deal of
attention for biomedical applications. Depending on their size, shape,
degree of aggregation, and local environment, gold nanoparticles can appear
red, blue, or other colors. These visible colors reflect the underlying
coherent oscillations of conduction-band electrons ("plasmons") upon
irradiation with light of appropriate wavelengths. These plasmons underlie
the intense absorption and elastic scattering of light, which in turn forms
the basis for many biological sensing and imaging applications of gold
nanoparticles. The brilliant elastic light-scattering properties of gold
nanoparticles are sufficient to detect individual nanoparticles in a visible
light microscope with approximately 10 (2) nm spatial resolution. Despite
the great excitement about the potential uses of gold nanoparticles for
medical diagnostics, as tracers, and for other biological applications,
researchers are increasingly aware that potential nanoparticle toxicity must
be investigated before any in vivo applications of gold nanoparticles can
move forward. In this Account, we illustrate the importance of surface
chemistry and cell type for interpretation of nanoparticle cytotoxicity
studies. We also describe a relatively unusual live cell application with
gold nanorods. The light-scattering properties of gold nanoparticles, as
imaged in dark-field optical microscopy, can be used to infer their
positions in a living cell construct. Using this positional information, we
can quantitatively measure the deformational mechanical fields associated
with living cells as they push and pull on their local environment. The
local mechanical environment experienced by cells is part of a complex
feedback loop that influences cell metabolism, gene expression, and
migration.
PMID: 18712884

Nanomed. 2008 Aug;3(4):543-53.
Gold nanoparticle-based assays for the detection of biologically relevant
molecules.
  White KA, Rosi NL.Department of Chemistry, University of Pittsburgh,
Pittsburgh, PA 15260, USA.
  Metallic nanoparticles of different sizes, shapes and compositions are
being avidly explored as materials for next-generation biological labels,
therapeutic agents, 'artificial viruses' and diagnostic probes. Gold
nanoparticles especially, are making a major impact in these areas, owing in
large part to their ease of functionality, low toxicity and unique optical
properties. In particular, gold nanoparticles are having a major role in the
development of highly sensitive and selective assays for biologically
relevant molecules. Some of the assays for nucleic acids and proteins
developed in the last 10 years outperform established methods and may soon
find routine use in hospital settings.
PMID: 18694316

Anal Chem. 2008 Jul 15;80(14):5487-93. Epub 2008 Jun 14.
Assessment of cytotoxicity of quantum dots and gold nanoparticles using
cell-based impedance spectroscopy.
  Male KB, Lachance B, Hrapovic S, Sunahara G, Luong JH. Biotechnology
Research Institute, National Research Council Canada, Montreal, Quebec,
Canada H4P 2R2.
  A continuous online technique based on electric cell-substrate impedance
sensing (ECIS) was demonstrated for measuring the concentration and time
response function of fibroblastic V79 cells exposed to nanomaterials such as
quantum dots (QDs) and fluorescent gold nanoparticles. The half-inhibition
concentration, (ECIS50), the required concentration to attain 50% inhibition
of the cytotoxic response, was estimated from the response function to
ascertain cytotoxicity during the course of measurement. The ECIS50 values
agreed well with the results obtained using the standard neutral red assay.
Cadmium selenide quantum dots showed direct cytotoxicity with the ECIS
assay. For the cadmium telluride quantum dots, significant toxicity could be
assigned to free cadmium, although additional toxicity could be attributed
to the QDs per se. The QDs synthesized with indium gallium phosphide and the
fluorescent gold nanoparticles were not cytotoxic.
PMID: 18553941

Mar Environ Res. 2008 Jul;66(1):131-3. Epub 2008 Feb 26.
Gold nanoparticles and oxidative stress in Mytilus edulis.
  Tedesco S, Doyle H, Redmond G, Sheehan D. Proteomics Research Group,
Department of Biochemistry, Environmental Research Institute, University
College Cork, Cork, Ireland.
  Little is known about potential environmental impact of nanoparticles.
Gold nanoparticles can cause unexpected biological responses. Here, Mytilus
edulis were exposed (24h) to gold-citrate nanoparticles (GNP), menadione and
both compounds simultaneously (GNP/menadione). Protein ubiquitination and
carbonylation were determined in gill, mantle and digestive gland, along
with traditional oxidative stress biomarkers; catalase activity and neutral
red retention time assay (haemolymph). 2DE gels were performed on gill
proteins (menadione; GNP/menadione). Our results reveal that GNP may induce
oxidative stress.
PMID: 18378295

Small. 2005 Mar;1(3):325-7.
Gold nanoparticles are taken up by human cells but do not cause acute
cytotoxicity.
  Connor EE, Mwamuka J, Gole A, Murphy CJ, Wyatt MD. Department of Basic
Pharmaceutical Sciences, University of South Carolina, Columbia, SC 29208,
USA.
PMID: 17193451

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