Azoanthracene-core structure as Cu²⁺-assisted CO sensing probe: Characterization, performance, and bioimaging.

Area of Science:

• Chemical Biology
• Biomedical Engineering
• Analytical Chemistry

Background:

• Endogenous carbon monoxide (CO) acts as a crucial signaling molecule in biological processes.
• Fluorescence imaging is vital for detecting CO, necessitating the development of sensitive fluorescent probes.
• Azobenzene derivatives offer potential as fluorescent probes due to their tunable photophysical properties.

Purpose of the Study:

• To design and synthesize novel azobenzene-based fluorescent probes for endogenous CO detection.
• To investigate the structure-performance relationship of these probes with varying substituents.
• To evaluate the optimal probe's efficacy in sensing Cu²⁺ and CO, including its bioimaging capabilities.

Main Methods:

• Synthesis and characterization of four azobenzene derivatives (A1-A4).
• Photophysical parameter determination and spectral response analysis to Cu²⁺ and CO.
• Investigation of Cu²⁺ quenching and CO sensing mechanisms.
• Bioimaging of endogenous CO in HeLa cells using the optimal probe.

Main Results:

• Probe A1, lacking substituents, demonstrated efficient fluorescence quenching by Cu²⁺ (PLQY from 0.33 to 0.02).
• CO deoxidization restored A1's fluorescence (PLQY to 0.32) within 180 seconds.
• A1 functions via static sensing, forming a 1:1 non-fluorescent complex with Cu²⁺.
• Successful bioimaging of endogenous CO in HeLa cells was achieved with probe A1.

Conclusions:

• Azobenzene derivative A1 is an effective fluorescent probe for detecting endogenous CO.
• The probe exhibits a rapid and reversible response to CO in the presence of Cu²⁺.
• A1 shows significant potential for bioimaging applications in cellular environments.