In vitro and in vivo two-photon luminescence imaging of single gold nanorods
- Haifeng Wang*,
- Terry B. Huff†,
- Daniel A. Zweifel†,
- Wei He†,
- Philip S. Low†,
- Alexander Wei†,‡, and
- Ji-Xin Cheng*,†,§
- *Weldon School of Biomedical Engineering and †Department of Chemistry, Purdue University, West Lafayette, IN 47907
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Edited by Y. Ron Shen, University of California, Berkeley, CA (received for review June 11, 2005)
Abstract
Gold nanorods excited at 830 nm on a far-field laser-scanning microscope produced strong two-photon luminescence (TPL) intensities, with a cos4 dependence on the incident polarization. The TPL excitation spectrum can be superimposed onto the longitudinal plasmon band, indicating a plasmon-enhanced two-photon absorption cross section. The TPL signal from a single nanorod is 58 times that of the two-photon fluorescence signal from a single rhodamine molecule. The application of gold nanorods as TPL imaging agents is demonstrated by in vivo imaging of single nanorods flowing in mouse ear blood vessels.
Footnotes
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↵ ‡To whom correspondence may be addressed at: Department of Chemistry, 560 Oval Drive, West Lafayette, IN 47907. E-mail: alexwei{at}purdue.edu. §To whom correspondence may be addressed at: Weldon School of Biomedical Engineering, Purdue University, 500 Central Drive, West Lafayette, IN 47907. E-mail: jcheng{at}purdue.edu.
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Author contributions: P.S.L., A.W., and J.-X.C. designed research; H.W. and T.B.H. performed the optical experiments; D.A.Z. prepared the nanorods and provided the TEM image; W.H. handled the mouse subject; and J.-X.C. wrote the paper.
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Conflict of interest statement: No conflicts declared.
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This paper was submitted directly (Track II) to the PNAS office.
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Abbreviations: TPL, two-photon luminescence; TPF, two-photon fluorescence.
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↵ ¶ The animal study protocol has been approved by Purdue University Animal Care and Use Committee (no. 96-069-02).
- Copyright © 2005, The National Academy of Sciences
