Fabrication of photostable PEGylated polymer nanoparticles from AIE monomer and trimethylolpropane triacrylate

Biocompatible and stable fluorescent polymer nanoparticles play significant roles in bioimaging and biomedical applications due to their convenient preparation strategies and unique properties. However, the construction methods are still limited now. Herein novel water dispersible and bright fluorescent polymer nanoparticles (PhE-TT-PEG FPNs) with great biocompatibility and stability have been facilely fabricated, and their cellular imaging applications were successfully demonstrated. The PhE-TT-PEG FPNs were readily prepared by self-assembly of amphiphilic copolymer PhE-TT-PEG, which was synthesized through free radical polymerization in one pot from AIE monomer PhE, trifunctional cross-linker TT, and biofavorable monomer PEGMA. A series of characterizations have been conducted to confirm the successful synthesis of PhE-TT-PEG, including gel permeation chromatography, X-ray photoelectron spectroscopy, FTIR spectroscopy, and ¹H NMR spectroscopy. The morphology and optical properties of PhE-TT-PEG FPNs have been tested by transmission electron microscopy, dynamic light scattering, UV-Visible absorption spectroscopy and fluorescence spectroscopy. The PhE-TT-PEG FPNs can emit strong fluorescence with a high quantum yield of 40%, and they also demonstrate superb water dispersibility, morphology stability, photostability and biocompatibility. Finally, the fluorescence imaging of HeLa cells with PhE-TT-PEG FPNs is investigated in detail.