Hemicyanine-Based Near-Infrared Fluorescence Off-On Probes for Imaging Intracellular and In Vivo Nitroreductase...

Area of Science:

• Biochemistry
• Chemical Biology
• Molecular Imaging

Background:

• Nitroreductase (NTR) enzymes are vital for activating prodrugs and degrading explosives.
• Existing fluorescent probes for NTR detection lack near-infrared (NIR) capabilities for biological applications.
• A need exists for sensitive and specific NIR probes for evaluating NTR activity in vivo.

Purpose of the Study:

• To synthesize and characterize novel NIR fluorescence probes for NTR activity detection.
• To investigate the probes' performance in terms of sensitivity, specificity, and cellular imaging.
• To explore the application of these probes in pharmaceutical and environmental contexts.

Main Methods:

• Synthesis of novel NIR probes (NIR-HCy-NO) based on a hemicyanine scaffold with a nitro group.
• Characterization of probe properties including fluorescence and absorbance spectra changes upon NTR interaction.
• Evaluation of catalytic efficiency, limit of detection (LOD), and live-cell imaging of NTR activity.

Main Results:

• NIR-HCy-NO probes exhibited low intrinsic fluorescence due to intramolecular charge transfer (ICT).
• NTR-mediated conversion of the nitro to amine group resulted in significant fluorescence enhancement.
• The developed probe demonstrated superior performance compared to existing probes for NTR activity imaging and exhibited reactivity with mitochondrial NTR in live cells.

Conclusions:

• NIR-HCy-NO probes are effective tools for sensitive detection and imaging of NTR activity.
• These probes show great potential for applications in drug development, environmental monitoring, and in vivo biological imaging.
• The study highlights the utility of NIR probes for advancing the understanding of NTR-related biological processes.