In vitro and in vivo two-photon luminescence imaging of single gold nanorods

Gold nanorods excited at 830 nm on a far-field laser-scanning microscope produced strong two-photon luminescence (TPL) intensities, with a cos(4) 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.

• NS
  National Science Foundation

  Awards: 0210445, 0243496
• PU
  Purdue University
• NI
  National Institutes of Health
• DO
  Division of Chemistry