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Proceedings Paper

Plasmonic biodegradable gold nanoclusters with high NIR-absorbance for biomedical imaging
Author(s): Robert Stover; Avinash Murthy; Sai Gourisankar; Golay Nie; Miguel Martinez; Thomas Truskett; Konstantin Sokolov; Keith Johnston
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Paper Abstract

Gold plasmonic nanoparticles are receiving attention for a variety of types of NIR optical biomedical imaging including photoacoustic imaging. Herein we present a novel method to assemble equilibrium gold nanoclusters from 5 nm primary gold nanospheres, which exhibit high near-infrared (NIR) absorbance and subsequently fully dissociate back to primary particles, which has the potential to enable renal clearance. The nanoparticle assembly is manipulated via controlling colloidal interactions, specifically electrostatic repulsion and depletion attraction. The charge on the primary ~5 nm gold nanospheres is tailored via place exchange reactions with a variety of biocompatible ligands such as citrate, lysine and cysteine. The primary particles form clusters upon addition of a biodegradable polymer, PLA(1k)-b- PEG(10k)-b-PLA(1k), followed by controlled solvent evaporation. The cluster size may be tuned from 20-40 nm in diameter by manipulating the gold and polymer concentrations along with the solvent evaporation extent. Salt is also added to increase the NIR absorbance and reduce the nanocluster size by reducing polymer adsorption. The adsorption of the polymer onto the Au surfaces effectively quenches the nanoclusters. High NIR absorption facilitates photoacoustic imaging, even for the small cluster sizes. In response to acidic cellular pH environments, the polymer degrades and the clusters dissociate back to primary particle on the order of 5 nm, which are small enough for renal clearance.

Paper Details

Date Published: 24 March 2014
PDF: 7 pages
Proc. SPIE 8955, Colloidal Nanoparticles for Biomedical Applications IX, 89550T (24 March 2014); doi: 10.1117/12.2040289
Show Author Affiliations
Robert Stover, The Univ. of Texas at Austin (United States)
Avinash Murthy, The Univ. of Texas at Austin (United States)
Sai Gourisankar, The Univ. of Texas at Austin (United States)
Golay Nie, The Univ. of Texas at Austin (United States)
Miguel Martinez, The Univ. of Texas at Austin (United States)
Thomas Truskett, The Univ. of Texas at Austin (United States)
Konstantin Sokolov, The Univ. of Texas at Austin (United States)
The Univ. of Texas M.D. Anderson Cancer Ctr. (United Kingdom)
Keith Johnston, The Univ. of Texas at Austin (United States)

Published in SPIE Proceedings Vol. 8955:
Colloidal Nanoparticles for Biomedical Applications IX
Wolfgang J. Parak; Marek Osinski; Kenji I. Yamamoto, Editor(s)

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