Biocompatible zwitterionic phosphorylcholine polymers with aggregation-induced emission feature

Two biocompatible zwitterionic phosphorylcholine polymers with aggregation-induced emission feature were synthesized and self-assembled into fluorescent nanoparticles for cell imaging. [Display omitted] •Two zwitterionic phosphorylcholine polymers were prepared.•The polymers had aggregation-induced emission feature.•The polymers formed fluorescent polymeric nanoparticles (FPNs) in water.•The FPNs showed ultra-low critical micelle concentration.•The FPNs exhibited excellent biocompatibility. Two novel zwitterionic phosphorylcholine polymers (MTP1 and MTP2) with aggregation-induced emission (AIE) feature were prepared through reversible addition fragmentation chain transfer polymerization between an AIE monomer with vinyl end group and a zwitterionic phosphorylcholine monomer. The synthesized copolymers were characterized and confirmed by 1H NMR, FT-IR, and X-ray photoelectron spectra. By introduction of the zwitterionic phosphorylcholine component, the synthesized copolymers showed amphiphilic properties and tended to self-assemble into fluorescent polymeric nanoparticles (FPNs) in water. The dynamic light scattering results indicated the size distribution of the MTP1 FPNs was 345±22nm, and that of the MTP2 FPNs was 147±36nm. The transmission electron microscopy results demonstrated spherical nanoparticle morphology for the FPNs. The high dispersibility of the FPNs in water was proved by the UV–vis absorption study with high transmittance of the solution. Fluorescent spectra of the prepared FPNs revealed bright green fluorescence with high fluorescence quantum yield of 45% for MTP1 and 34% for MTP2. More importantly, the FPNs showed excellent particle stability with low critical micelle concentration of 0.008mgmL−1 for MTP1 and 0.007mgmL−1 for MTP2. The cytotoxicity evaluation confirmed high cytocompatibility of the prepared FPNs at different concentrations, and demonstrated excellent biocompatibility for cell imaging. In virtue of the high-performance MTP1 and MTP2 FPNs, including high water dispersion, good particle stability, and excellent cytocompatibility, this work would inspire more researches about high-performance biocompatible fluorescent polymers for biomedical application.