Fast-Response Mitochondria-Targeted Fluorescent Probe for H₂S Imaging in Tumors and Inflammation

Area of Science:

• Chemical Biology
• Biomedical Imaging
• Molecular Probes

Background:

• Hydrogen sulfide (H₂S) plays a crucial role in physiological and pathological processes.
• Effective real-time monitoring of dynamic H₂S changes is essential for understanding disease development.
• Current visualization methods for H₂S often lack specificity, sensitivity, or speed.

Purpose of the Study:

• To develop a novel near-infrared (NIR) fluorescent probe for sensitive and rapid detection of H₂S.
• To investigate the probe's performance in biological imaging, including cellular and in vivo applications.
• To explore the potential of the probe in studying H₂S-related biological processes, such as inflammation.

Main Methods:

• Synthesis of a NIR fluorescent probe (HCy-SSPy) utilizing a hemicyanine (HCy-NH₂) fluorophore and asymmetric pyridyl disulfides (SSPy) recognition unit.
• Characterization of the probe's spectral properties and response to H₂S, focusing on NIR emission at 765 nm.
• Evaluation of probe's selectivity, sensitivity, and response time for H₂S detection.
• Assessment of probe's cytotoxicity, subcellular localization (mitochondria), and cell imaging capabilities.
• In vivo imaging of H₂S in tumor-bearing mice and application in detecting H₂S during inflammatory processes.

Main Results:

• The HCy-SSPy probe exhibited a significant NIR 'turn-on' fluorescence signal at 765 nm upon reaction with H₂S.
• The probe demonstrated excellent selectivity, high sensitivity, and rapid H₂S detection capabilities within approximately 5 seconds.
• HCy-SSPy showed low cytotoxicity and specific localization within mitochondria, with effective cell imaging performance.
• Successful in vivo imaging of H₂S in tumor-bearing mice was achieved.
• The probe showed potential for detecting H₂S in inflammatory processes.

Conclusions:

• HCy-SSPy is a highly effective NIR fluorescent probe for rapid and sensitive real-time imaging of H₂S.
• The probe's characteristics make it suitable for biological applications, including cellular imaging and in vivo studies.
• HCy-SSPy holds promise for advancing the study of H₂S in disease mechanisms, particularly in oncology and inflammation.