An activatable azophenyl fluorescent probe for hypoxic fluorescence imaging in living cells

Area of Science:

• Biomedical Engineering
• Chemical Biology
• Oncology

Background:

• Cellular hypoxia is a critical pathological process in numerous diseases, particularly cancer.
• Early detection of tumor hypoxia is vital for effective diagnosis and treatment strategies.
• Current hypoxia fluorescence probes face limitations like aggregation-caused quenching, hindering aqueous imaging.

Purpose of the Study:

• To design and synthesize an activatable hypoxia fluorescence probe with improved imaging capabilities.
• To overcome the limitations of aggregation-caused quenching in existing hypoxia probes.
• To enable sensitive and specific fluorescence imaging of hypoxic environments in live cancer cells.

Main Methods:

• Covalent linkage of aggregation-induced emission (AIE) luminogens to the azobenzene hypoxic recognition group.
• Design of a probe that is non-fluorescent in the presence of light due to photosensitive azo bonds.
• Demonstration of probe activation via intracellular azoreductase cleavage, yielding fluorescent AIE derivatives.

Main Results:

• The developed probe exhibits minimal fluorescence in solution and solid states under light excitation.
• Intracellular cleavage by azoreductase generates highly fluorescent amino derivatives with AIE characteristics.
• Increased fluorescence intensity correlates with decreased cellular oxygen concentration, enabling effective hypoxia detection.

Conclusions:

• The novel probe provides a sensitive and activatable method for detecting cellular hypoxia.
• This molecular design approach broadens the scope for developing advanced hypoxia fluorescent probes.
• The probe is suitable for fluorescence imaging in live cancer cells, aiding in tumor hypoxia assessment.