Hairy fluorescent nanoparticles from one-pot click chemistry and atom transfer radical emulsion polymerization

Abstract

Well-defined hairy and crosslinked fluorescent nanoparticles with diameters in the range 70-220 nm were obtained from simultaneous copper-catalyzed alkyne-azide cycloaddition (CuAAC) and atom transfer radical emulsion polymerization (ATREP) of a mixture of styrene, divinylbenzene, 4-vinylbenzylazide and 7-propinyloxycoumarin (Cr), using bromide-terminated poly(ethylene glycol) (PEG) as macroinitiator, Tween-20 as emulsifier, copper(I) bromide as catalyst and pentamethyldiethylenetriamine as ligand. The generation of biocompatible PEG brushes and the introduction of fluorescent functionalities as well as crosslinking of nanoparticles were realized in one step. In order to verify that functionalization and propagation of polymer chains could be realized in a controlled manner by one-pot simultaneous ATREP and CuAAC, linear block copolymers of PEG and polystyrene (PS) with partially clicked pendent Cr groups (PEG-b-(PS-c-Cr)) were synthesized. All prepared PEG-b-(PS-c-Cr) copolymers had a controlled molecular weight and defined molecular structure. The hairy fluorescent nanoparticles exhibit a low cytotoxicity and could find applications in cell labeling. © 2013 Society of Chemical Industry.