title: Isolation and characterization of precise dye/dendrimer ratios.
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.
authors.affiliation: Department of Chemistry, University of Michigan, Ann Arbor, Michigan, 48109-1055 (USA).
authors.forename: Casey A
authors.initials: CA
authors.lastname: Dougherty
authors.forename: Joseph C
authors.initials: JC
authors.lastname: Furgal
authors.forename: Mallory A
authors.initials: MA
authors.lastname: van Dongen
authors.forename: Theodore
authors.initials: T
authors.lastname: Goodson
authors.forename: Mark M
authors.initials: MM
authors.lastname: Banaszak Holl
authors.forename: Janet
authors.initials: J
authors.lastname: Manono
authors.forename: Stassi
authors.initials: S
authors.lastname: DiMaggio
mesh_terms: D002851:Chromatography, High Pressure Liquid; D056148:Chromatography, Reverse-Phase; D057930:Click Chemistry; D050091:Dendrimers / Q000737:chemistry* / Q000302:isolation & purification; D019793:Fluorescein / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry; D011073:Polyamines / Q000737:chemistry; D012235:Rhodamines / Q000737:chemistry
chemical_list: C114557:5-carboxytetramethylrhodamine succinimidyl ester; D050091:Dendrimers; D005456:Fluorescent Dyes; C531249:Poly(amidoamine); D011073:Polyamines; D012235:Rhodamines; D019793:Fluorescein
keywords: click chemistry; dendrimers; dyes/pigments; fluorescent probes; nanostructures