Facile Synthesis of Stable and Water-Dispersible Multihydroxy Conjugated Polymer Nanoparticles with Tunable Size by Dendritic Cross-Linking.

A new strategy has been developed to synthesize conjugated polymer (CP) nanoparticles (CPNs) with numerous surface hydroxyl groups via click chemistry between a CP and hyperbranched polyglycerol (HPG) in miniemulsion. Laser light scattering and TEM characterizations indicate that the synthesized CPNs have spherical shapes with uniform sizes tunable in the range of 40-210 nm simply by adjusting the feed amount of the oil phase or surfactant in the miniemulsion. The obtained CPNs have good water dispersibility and orange emission with high fluorescence quantum yields of 23 ± 2%. Detailed spectroscopy studies reveal that the CPNs have shown stable fluorescence against pH change, ionic strength variation, or protein disturbance. In addition, they have good photostability and low cytotoxicity, which make them an ideal fluorescent moiety for cellular imaging. This study provides important fundamental understanding of cross-linking modification on CP to form CPNs, which will stimulate further research on synthesis and application of advanced CPNs.