In vivo excitation of nanoparticles using luminescent bacteria

Proc Natl Acad Sci U S A. 2012 Jun 5;109(23):8890-5. doi: 10.1073/pnas.1204516109. Epub 2012 May 21.

Abstract

The lux operon derived from Photorhabdus luminescens incorporated into bacterial genomes, elicits the production of biological chemiluminescence typically centered on 490 nm. The light-producing bacteria are widely used for in vivo bioluminescence imaging. However, in living samples, a common difficulty is the presence of blue-green absorbers such as hemoglobin. Here we report a characterization of fluorescence by unbound excitation from luminescence, a phenomenon that exploits radiating luminescence to excite nearby fluorophores by epifluorescence. We show that photons from bioluminescent bacteria radiate over mesoscopic distances and induce a red-shifted fluorescent emission from appropriate fluorophores in a manner distinct from bioluminescence resonance energy transfer. Our results characterizing fluorescence by unbound excitation from luminescence, both in vitro and in vivo, demonstrate how the resulting blue-to-red wavelength shift is both necessary and sufficient to yield contrast enhancement revealing mesoscopic proximity of luminescent and fluorescent probes in the context of living biological tissues.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Escherichia coli
  • Female
  • Fluorescence*
  • Luminescence*
  • Luminescent Agents / metabolism*
  • Luminescent Measurements
  • Mice
  • Mice, Inbred BALB C
  • Molecular Imaging / methods*
  • Nanoparticles / chemistry*
  • Quantum Dots
  • Staphylococcus aureus

Substances

  • Luminescent Agents