A novel nitroreductase-responsive turn-off fluorescent probe based on AIEgen and its bioimaging application

• Published in: Journal of molecular structure 2023-12, Vol.1294, p.136483, Article 136483
• Main Authors: Li, Ruxin, Zheng, Juan, Wang, Yule, Bai, Wenjun, Lu, Yang, Geng, Jiahou, Feng, Jiahe, Wang, Ning, Zhao, Yufen, Wang, Jinhui
• Format: Article
• Language: English
• Subjects: Aggregation-induced emission; Bioimaging; Fluorescence quenching; Nitroreductase
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2023.136483

•A novel NTR-responsive “turn off” fluorescent probe TPEDCH-PBN was designed.•TPEDCH-PBN exhibited typical aggregation-induced emission (AIE) properties.•TPEDCH-PBN showed high selectivity and low detection limit towards nitroreductase.•TPEDCH-PBN displayed time-dependent fluorescence quenching behaviors.•The molecular design strategy was elaborated by DFT and docking calculations. Nitroreductase (NTR) is frequently employed as a biomarker to assess the level of hypoxia in tumor tissues. To date, the majority of NTR-reactive probes have focused on the luminescence "turn on" characteristic, which has been plagued by background interferences. In this study, we present the first report of an NTR-responsive "turn-off" fluorescent probe, TPEDCH-PBN, based on AIEgen. This probe exhibits typical aggregation-induced emission (AIE) properties in high PBS fraction, which may be attributed to the restriction of intramolecular motions (RIM) effect. DFT/TD-DFT calculations were employed to determine the discrepancies in structure and electron density distribution among TPEDCH, TPEDCH-PBNOH and TPEDCH-PBN. Additionally, docking calculations were utilized to elucidate the structure-function relationship between the probe and NTR, revealing a favorable structural and spatial match. Photophysical investigations demonstrated the probe's high selectivity towards NTR with the detection limit of 0.68 μg/mL. The dynamic quenching process of TPEDCH-PBN upon NTR was examined, and the quenching constant Ksv was determined to be 53.6 g−1.L. In addition, the NTR detection ability of probe TPEDCH-PBN as well as its time-dependent fluorescence quenching behaviors were confirmed by cell imaging of probe in A549 cells. Overall, this study proposed a novel molecular design approach for the biomarker detection probe, which may prove to be more extensively applicable. Schematic Representation of the NTR-responsive turn-off fluorescent probe based on AIEgen and its bioimaging application [Display omitted]