Synthesis and properties of fluorescent dyes conjugated to hyperbranched polyglycerols

Convergent syntheses of polyglycerol hyperbranched polymers containing fluorescent labels (fluorescein or perylene diimide (PDI)) at their core are presented. The hyperbranched polyglycerol (HPG) precursors were synthesized using a one step polymerization reaction wherein the initiator leaves a single reactive group for dye functionalization. For further site isolation, allylated HPG was synthesized allowing cross-linking via ring closing metathesis and subsequent dihydroxylation to produce water-soluble, fluorescent nanoparticles. The dyes produced showed improvements in photostability, water solubility, or quantum yield, depending on both the dye used and cross-linking. These fluorescent nanoparticles outperformed similar dyes that incorporated linear polyethylene glycol (PEG) polymers.