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Proceedings Paper

Upconverting fluorescent nanoparticles for biodetection and photoactivation
Author(s): Kai Huang; WenKai Li; Muthu Kumara Gnanasammandhan Jayakumar; Yong Zhang
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Paper Abstract

Fluorophores including fluorescent dyes/proteins and quantum dots (QDs) are used for fluorescence-based imaging and detection. These are based on ‘downconversion fluorescence’ and have several drawbacks: photobleaching, autofluorescence, short tissue penetration depth and tissue photo-damage. Upconversion fluorescent nanoparticles (UCNs) emit detectable photons of higher energy in the short wavelength range upon irradiation with near-infrared (NIR) light based on a process termed ‘upconversion’. UCNs show absolute photostability, negligible autofluorescence, high penetration depth and minimum photodamage to biological tissues. Lanthanide doped nanocrystals with nearinfrared NIR-to-NIR and/or NIR-to-VIS and/or NIR-to-UV upconversion fluorescence emission have been synthesized. The nanocrystals with small size and tunable multi-color emission have been developed. The emission can be tuned by doping different upconverting lanthanide ions into the nanocrystals. The nanocrystals with core-shell structure have also been prepared to tune the emission color. The surfaces of these nanocrystals have been modified to render them water dispersible and biocompatible. They can be used for ultrasensitive interference-free biodetection because most biomolecules do not have upconversion properties. UCNs are also useful for light based therapy with enhanced efficiency, for example, photoactivation.

Paper Details

Date Published: 29 March 2013
PDF: 6 pages
Proc. SPIE 8635, Advances in Photonics of Quantum Computing, Memory, and Communication VI, 863504 (29 March 2013); doi: 10.1117/12.2002754
Show Author Affiliations
Kai Huang, National Univ. of Singapore (Singapore)
WenKai Li, National Univ. of Singapore (Singapore)
Muthu Kumara Gnanasammandhan Jayakumar, National Univ. of Singapore (Singapore)
Yong Zhang, National Univ. of Singapore (Singapore)

Published in SPIE Proceedings Vol. 8635:
Advances in Photonics of Quantum Computing, Memory, and Communication VI
Zameer U. Hasan; Philip R. Hemmer; Hwang Lee; Charles M. Santori, Editor(s)

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