Synthesis and cell imaging applications of amphiphilic AIE-active poly(amino acid)s

The poly(amino acid)s based biomaterials have attracted great research attention over the past few decades because of their biocompatibility, biodegradability and well designability. Although much progress has achieved in the synthesis and biomedical applications of poly(amino acid)s, the synthesis of luminescent poly(amino acid)s has been rarely reported. In this work, novel amphiphilic luminescent poly(amino acid)s with aggregation-induced emission (AIE) feature have been synthesized by a new approach of controlling N-carboxy anhydride (NCA) ring-opening polymerization, in which hydrophobic 2-(4-aminophenyl)-3-(10-hexadecyl-4H-phenothiazin-3-yl)acrylonitrile (Phe-NH₂) with AIE feature was used as initiator and hydrophilic oligomeric glycol functionalized glutamate (OEG-glu) NCA was acted as monomer. The successful synthesis of final Phe-OEG-Pglu polymers was confirmed by different characterization techniques. Phe-OEG-Pglu polymers possess amphiphilic properties and can self-assemble into luminescent polymeric nanoparticles (LPNs). Based on cellular imaging experiments, we demonstrated that Phe-OEG-Pglu LPNs have great potential for bio-imaging applications due to their attractive properties including strong fluorescence intensity, great water dispersibility, excellent biocompatibility and high cellular uptake efficiency.