“AIE+ESIPT” Based Naphthothiazole Fluorescent Probes for Live Cell Imaging

Dual-functional organic fluorophores with aggregation induced emission (AIE) behavior and excited-state intramolecular proton transfer (ESIPT) behavior are of great significance to the design of imaging probes to bioimage systems. However, the pursuit of probes exhibiting dual AIE+ESIPT effects for live cell imaging remains an ongoing research challeng. Herein, we have successfully developed naphthothiazole fluorescent probes, HNBT-H and HNBT-G, based on the "AIE+ESIPT" effect. These probes were designed by incorporating responsive units for β-galactosidase (β-gal) and H2O2 into the pre-existing "AIE+ESIPT" HNBT fluorophore framework. The HNBT-H probe demonstrated the capability to distinguish various levels of H2O2. Furthermore, the applicability of HNBT-H and HNBT-G have been examined in in living systems. These probes exhibit a good biocompatibility and low toxicity, the cell imaging experiments demonstrate the capability of HNBT-H and HNBT-G for fluorescence visualization in response to β-gal and H2O2 in RAW264.7 cells and PC12 cells.