Synthesis of amphiphilic AIE fluorescent nanoparticles via CO2 involved multicomponent reaction and its biological imaging potential

Fluorescent materials with aggregation-induced emission (AIE) have standout as one of the most interesting candidates for biomedical applications. The development of new methods for fabrication of AIE-active materials will surely advance their applications in related fields. In this work, we reported a novel method for preparation of AIE-active luminescent polymer (Lys-PEG-TPE) through a three-component reaction involving carbon dioxide (CO2) using lysine, Polyethylene glycol (PEG) and AIEgen as the reactants. On account of the introduction of PEG, Lys-PEG-TPE could well disperse in aqueous solution, while hydrophobic TPE will aggregate in the core of self-assembled nanoparticles, endowing the obvious enhancement of fluorescence intensity. Results from biological assays suggested that Lys-PEG-TPE exhibits almost no toxicity after incubation with HepG2 cells and its fluorescence can be clearly observed in cytoplasm after cell internalization. More importantly, the AIE feature of Lys-PEG-TPE could not only effectively solve the aggregation-induced quenching effect of traditional fluorescent molecules, the carboxyl groups of lysine could also be used for loading functional cationic ions (e.g., anticancer drugs or imaging agents) to fabricate multifunctional theranostic and imaging composites. Considering the benign reaction conditions, high atom economy, and well tunability of reactants of multicomponent reactions, this strategy should be of broad interesting for fabrication of multifunctional AIE-active materials for biomedical applications.