Self-carried AIE nanoparticles for in vitro non-invasive long-term imaging

Fluorescent organic nanoparticles (NPs) based on aggregation-induced emission (AIE)-active molecules, are widely applied as non-invasive tools in bio-imaging and demonstrate great potential for studying physiological and pathological processes. In this paper, we report the synthesis of highly emissive AIEgen-based NPs (SCA NPs) via reprecipitation without any carriers as long-term cell trackers. Uniformly sized SCA NPs enjoy the advantages of high brightness, good stability, large Stokes shift, good biocompatibility, and high photostability. The SCA NPs were successfully applied for in vitro bio-imaging of HeLa cells with an excellent cancer cell uptake. In addition, a strong fluorescence from SCA NPs can still be clearly observed in HeLa cells after incubation for six generations over 15 days. Thus, the SCA NPs could be ideal fluorescent probes for non-invasive long-term cellular imaging. The AIE-active NPs display superior performance and provide a basis for the development of fluorescent organic probes for monitoring biological processes.