Fabrication of amphiphilic fluorescent nanoparticles with an AIE feature via a one-pot clickable mercaptoacetic acid locking imine reaction: synthesis, self-assembly and bioimaging

Fluorescent organic nanoparticles (FNPs) with intensive luminescence are widely applied in various biomedical fields, but the malicious aggregation caused quenching effect of conventional organic dyes hampers their biomedical application. In this work, we report a facile and highly efficient method for fabrication of FNPs with a stable cross-linked structure and enhanced luminescence via a one-pot mercaptoacetic acid locking imine reaction, in which a hydrophobic aggregation induced emission (AIE) dye (AHAn) and hydrophilic polylysine (Plys) were used as two reaction components, while mercaptoacetic acid acted as the lock to conjugate AHAn and Plys. The final amphiphilic fluorescent materials (Plys&AHAn&Plys) are readily formed FNPs in aqueous solution and exhibit high water dispersibility and strong luminescence. Furthermore, Plys&AHAn&Plys FNPs display low toxicity and good biological imaging performance. Altogether, we have developed a rather facile one-pot multicomponent reaction (MCR) to fabricate AIE active FNPs, which shows many promising properties for biomedical applications. More importantly, the MCR strategy could also be used for fabrication of many other multifunctional AIE active polymeric nanoprobes due to its good substrate adaptability and high efficiency.