A multifunctional nucleoside-based AIEgens sensor (TPEPy-dU) was constructed for visual screening of Hg²⁺, determine the reversible response of Fe³⁺and biothiols, and applied for cell imaging, and drug-free bacterial killing. The TPEPy-dU displayed 10-fold fluorescence enhancement at 540 nm of emission in response to trace Hg²⁺ions with 10 nM of LOD, which can be immediately quenched by adding Fe³⁺or GSH/Cys-containing sulfhydryl groups. Moreover, their bacterial staining efficiency closely correlates with their antibacterial efficacy as they demonstrated comparatively higher antibacterial activity against Gram-positive bacteria than Gram-negative bacteria. The drug-free antibacterial results involved the stating prominent surface damages at the sites of interactions between bacterial cells and TPEPy-dU that were further verified by CLSM and SEM images. It can be applied as a potential fluorescent agent to explore the related antibacterial mechanisms for treating and monitoring bacterial infectionsin vivodue to their nontoxic nature. Compared with conventional sensors and antibacterial therapies, these findings elevated the synthetic strategies of fluorescent probes and represented an advanced antibacterial agent wearing quaternary ammonium cationic with low resistance in clinical diagnosis.

Graphic Abstract: Multifunctional Nucleoside-AIEgens for Reversible Response of Hg²⁺and Fe³⁺/GSH/Cys, Bioimaging,and Antibacterial.

Ms. Yating Zeng, a master student atInstitute for Advanced Study in Shenzhen University is the first author, and Prof. Hai Xiong is the corresponding author.This work is supported by the Science and Technology Innovation Commission of Shenzhen, China (JCYJ20210324095607021 to HX), the Special Project of Key Fields of Universities in Guangdong Province, China (2021ZDZX2047 to HX), and Top Young Talent of the Pearl River Talent Recruitment Program, China.

The research paper linked：https://doi.org/10.1016/j.aca.2023.341924