Facile preparation of biocompatible and robust fluorescent polymeric nanoparticles via PEGylation and cross-linking.

Novel cross-linked copolymers of PEG-IM-PhNH2 are successfully synthesized through PEGylation via radical polymerization of 2-isocyanatoethyl methacrylate and poly(ethylene glycol) monomethyl ether methacylate and subsequent cross-linking with an amino-terminated aggregation-induced emission fluorogen. Such obtained amphiphilic copolymers can self-assemble to form uniform fluorescent polymeric nanoparticles (FPNs) and be utilized for cell imaging. These cross-linked FPNs are demonstrated good water dispersibility with ultralow critical micelle concentration (∼ 0.002 mg mL(-1)), uniform morphology (98 ± 2 nm), high red fluorescence quantum yield, and excellent biocompatibility. More importantly, this novel strategy of fabricating cross-linked FPNs paves the way to the future development of more robust and biocompatible fluorescent bioprobes.