Isolation and characterization of precise dye/dendrimer ratios

Chemistry. 2014 Apr 14;20(16):4638-45. doi: 10.1002/chem.201304854. Epub 2014 Mar 6.

Abstract

Fluorescent dyes are commonly conjugated to nanomaterials for imaging applications using stochastic synthesis conditions that result in a Poisson distribution of dye/particle ratios and therefore a broad range of photophysical and biodistribution properties. We report the isolation and characterization of generation 5 poly(amidoamine) (G5 PAMAM) dendrimer samples containing 1, 2, 3, and 4 fluorescein (FC) or 6-carboxytetramethylrhodamine succinimidyl ester (TAMRA) dyes per polymer particle. For the fluorescein case, this was achieved by stochastically functionalizing dendrimer with a cyclooctyne "click" ligand, separation into sample containing precisely defined "click" ligand/particle ratios using reverse-phase high performance liquid chromatography (RP-HPLC), followed by reaction with excess azide-functionalized fluorescein dye. For the TAMRA samples, stochastically functionalized dendrimer was directly separated into precise dye/particle ratios using RP-HPLC. These materials were characterized using (1)H and (19)F NMR spectroscopy, RP-HPLC, UV/Vis and fluorescence spectroscopy, lifetime measurements, and MALDI.

Keywords: click chemistry; dendrimers; dyes/pigments; fluorescent probes; nanostructures.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromatography, High Pressure Liquid
  • Chromatography, Reverse-Phase
  • Click Chemistry
  • Dendrimers / chemistry*
  • Dendrimers / isolation & purification
  • Fluorescein / chemistry
  • Fluorescent Dyes / chemistry*
  • Nanostructures / chemistry
  • Polyamines / chemistry
  • Rhodamines / chemistry

Substances

  • 5-carboxytetramethylrhodamine succinimidyl ester
  • Dendrimers
  • Fluorescent Dyes
  • Poly(amidoamine)
  • Polyamines
  • Rhodamines
  • Fluorescein