A facile one-pot Mannich reaction for the construction of fluorescent polymeric nanoparticles with aggregation-induced emission feature and their biological imaging.

Multicomponent reactions (MCRs) have recently attracted great attention as one of the most important tools for the construction of various organic compounds in modern organic chemistry. In this work, we introduced an efficient one-pot strategy to successfully fabricate the fluorescent polymeric nanoparticles (FPNs) with aggregation-induced emission (AIE) characteristic via the conjugation of hyperbranched polyamino compound polyethyleneimine (PEI), AIE dye (named as PhE-OH) and paraformaldehyde (PF) through a Mannich reaction. The final amphiphilies (PEI-PF-PhE) can self-assemble into micelles in aqueous solution. We demonstrated PEI-PF-PhE FPNs showed high water dispersity, intense orange-yellow fluorescence, excellent photostability, low toxicity and high cell imaging performance. As compared with other construction strategies, the one-pot Mannich reaction possesses a number of advantages, such as simplicity, atom economy, high-efficiency and multifunctional potential. Combined with the remarkable properties of the AIE-active FPNs and the one-pot Mannich reaction, we could expect that the strategy developed in this work should be a useful tool for construction of various AIE-active functional materials for biomedical applications.