Fabrication of cross-linked fluorescent polymer nanoparticles and their cell imaging applications

Novel aggregation induced emission (AIE) dye based cross-linked amphiphilic fluorescent polymers have been prepared facilely by a one pot method. This was carried out first by free radical polymerization between the AIE monomer (PhE) and glycidyl methacrylate (GM), then by the ring-opening reaction between GM and polyethyleneimine (PEI) to obtain the cross-linked polymer. The resultant cross-linked amphiphilic polymer was prone to self-assemble into stable nanoparticles with high water dispersibility due to the surplus amino groups and hydroxyl groups covered on the surface, which can also be further functionalized. The thus obtained nanoparticles demonstrated strong orange fluorescent emission with a quantum yield of about 41% owing to the AIE dyes in the cores of the nanoparticles. Biocompatibility evaluation and cell uptake behaviour of the nanoparticles were further investigated to explore their potential biomedical applications and the demonstrated excellent biocompatibility made them promising for cell imaging.