Tailoring Fluorescent Dyes To Optimize a Hybrid RGD-Tracer

Bioconjug Chem. 2016 May 18;27(5):1253-8. doi: 10.1021/acs.bioconjchem.6b00093. Epub 2016 Apr 28.


Quantitative assessment of affinity and kinetics is a critical component in the development of (receptor-targeted) radiotracers. For fluorescent tracers, such an assessment is currently not yet applied, while (small) changes in chemical composition of the fluorescent component might have substantial influence on the overall properties of a fluorescent tracer. Hybrid imaging labels that contain both a radiolabel and a fluorescent dye can be used to evaluate both the affinity (fluorescent label) and the in vivo distribution (radiolabel) of a targeted tracer. We present a hybrid label oriented and matrix-based scoring approach that enabled quantitative assessment of the influence of (overall) charge and lipophilicity of the fluorescent label on the (in vivo) characteristics of αvβ3-integrin targeted tracers. Systematic chemical alterations in the fluorescent dye were shown to result in a clear difference in the in vivo distribution of the different hybrid tracers. The applied evaluation technique resulted in an optimized targeted tracer for αvβ3-integrin, which combined the highest T/M ratio with the lowest uptake in other organs. Obviously this selection concept would also be applicable during the development of other (receptor-targeted) imaging tracers.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Fluorescent Dyes / chemistry*
  • Fluorescent Dyes / metabolism
  • Integrin alphaVbeta3 / metabolism
  • Isotope Labeling
  • Multimodal Imaging / methods*
  • Oligopeptides / chemistry*
  • Oligopeptides / metabolism
  • Optical Imaging
  • Radioactive Tracers
  • Tomography, Emission-Computed, Single-Photon


  • Fluorescent Dyes
  • Integrin alphaVbeta3
  • Oligopeptides
  • Radioactive Tracers
  • arginyl-glycyl-aspartic acid