A multifunctional AIEgen with high cell-penetrating ability for intracellular fluorescence assays, imaging and drug delivery

摘要

Aggregation-induced emission luminogens (AIEgens) with a definite structure-activity relationship play important roles in site-specific bio-imaging and applications. However, the lack of a clear structure- activity relationship for the excited-state intramolecular proton transfer (ESIPT) molecules, which are a series of powerful AIEgens, restricts their biological applications. Herein, the cell-penetrating capability of 4-N,N-dimethylaminoaniline salicylaldehyde Schiff-bases (Dss) with different substituents was investigated. The diethylamino functionalized ESIPT Schiff base (Dss-4-DEA) displayed high cell-penetrating capacity, making this simple AIEgen turn into a more powerful fluorescent functional material in biosystems. The Dss- 4-DEA was successfully used for a fluorescence assay of the intracellular Cu2+.Besides,theDss-4-DEA couldalsobeusedasanefficienttransmembranecarrier to drastically enhance the internalization of Dss-5-Cl to achieve two-color imaging. In addition, the Dss-4-DEA could be used to improve the transportation of anticancer drug curcumin (Cur) into HeLa cells, leading to increased apoptosis. The complete exploration of the structure-activity relationship of ESIPT molecules might supply lots of new applica- tions of AIE materials in biological systems.