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Proceedings Paper

Gold nanorods coupled with upconverting nanophosphors for targeted thermal ablation and imaging of bladder cancer cells (Conference Presentation)
Author(s): Suehyun K. Cho; Lih-Jen Su; Thomas W. Flaig; Wounjhang Park

Paper Abstract

NaYF4:Yb3+,Er3+ upconverting nanophosphors (UCNPs) are robust and stable nanoparticles that absorb near-infrared (NIR) photons and emit green and red visible photons through energy transfer upconversion. This mechanism provides UCNPs several advantages as a bioimaging agent over traditional fluorescence imaging agent in that NIR excitation allows high-contrast imaging without autofluorescence and that they can be used for deep-tissue imaging. However, additional surface modification of UCNPs is necessary for them to be biocompatible. We use an amphiphilic polymer (poly(maleic anhydride-alt-octadecene) (PMAO) and a hetero-functional polyethylene glycol with amine and thiol ends (NH2-PEG-SH)) to make the UCNPs water-soluble. This reaction yields a carboxylic group that allows functionalization with anti-epidermal growth factor receptor (aEGFR), which provides specific binding of UCNPs to EGFR-expressing bladder cancer cells. Additionally, the thiol ends of the PEGylated UCNPs are able to bind with gold nanorods (AuNRs) to create UCNP-AuNR complexes. The localized surface plasmon of the AuNR then allow localized heating of HTB9 bladder cancer cells, enabling in situ cell killing upon detection by UCNP fluorescence. Here, we report a successful synthesis, surface modification and conjugation of aEGFR functionalized UCNP-AuNR complexes and in vitro imaging and thermal ablation studies using them. Synthesis and surface modification of UCNP-AuNR complexes are confirmed by electron microscopy. Then, a combination of brightfield, NIR confocal fluorescence, and darkfield microscopy on the UCNP-AuNR treated bladder cancer cells revealed successful cancer targeting and imaging capabilities of the complex. Finally, cell viability assay showed that NIR irradiation of UCNP-AuNR conjugated cells resulted highly selective cell killing.

Paper Details

Date Published: 3 November 2016
PDF: 1 pages
Proc. SPIE 9930, Biosensing and Nanomedicine IX, 99300H (3 November 2016); doi: 10.1117/12.2238365
Show Author Affiliations
Suehyun K. Cho, Univ. of Colorado Boulder (United States)
Lih-Jen Su, Univ. of Colorado Denver (United States)
Thomas W. Flaig, Univ. of Colorado Denver (United States)
Wounjhang Park, Univ. of Colorado Boulder (United States)

Published in SPIE Proceedings Vol. 9930:
Biosensing and Nanomedicine IX
Hooman Mohseni; Massoud H. Agahi; Manijeh Razeghi, Editor(s)

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