Fluorescence imaging is a mainstay of biomedical research, allowing detection of molecular events in both fixed and living cells, tissues and whole animals. Such high resolution fluorescence imaging is hampered by unwanted signal from intrinsic background fluorescence and scattered light. The signal to background ratio can be improved by using extrinsic contrast agents and greatly enhanced by multispectral imaging methods. Unfortunately, these methods are insufficient for deep tissue imaging where high contrast and speedy acquisition are necessary. Fluorescence lifetime (FLT) is an inherent characteristic of each fluorescent species that can be independent of intensity and spectral properties. Accordingly, FLT-based detection provides an additional contrast mechanism to optical measurements. This contrast is particularly important in the near-infrared (NIR) due to relative transparency of tissue as well as the broad absorption and emission spectra of dyes that are active in this region. Here we report comparative analysis of signal distribution of several NIR fluorescent polymethine dyes in living mice and their correlations with lifetimes obtained in vitro using solution models. The FLT data obtained from dyes dissolved in serum albumin solution correlated well with FLTs measured in vivo. Thus the albumin solution model could be used as a good predictive model for in vivo FLT behavior of newly developed fluorescent reporters. Subsequent experiments in vivo, including monitoring slow release kinetics and detecting proteinuria, demonstrate the complementary nature of FLT for fluorescence intensity imaging.

Original languageEnglish
Title of host publicationReporters, Markers, Dyes, Nanoparticles, and Molecular Probes for Biomedical Applications
StatePublished - Jun 15 2009
EventReporters, Markers, Dyes, Nanoparticles, and Molecular Probes for Biomedical Applications - San Jose, CA, United States
Duration: Jan 26 2009Jan 29 2009

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
ISSN (Print)1605-7422


ConferenceReporters, Markers, Dyes, Nanoparticles, and Molecular Probes for Biomedical Applications
Country/TerritoryUnited States
CitySan Jose, CA


  • Biodegradable
  • Controlled-release
  • Diffuse optical imaging
  • Mice
  • Nanoparticle
  • Time-resolved


Dive into the research topics of 'In Vivoimaging with near-infrared fluorescence lifetime contrast'. Together they form a unique fingerprint.

Cite this