Intracellular Oxygen Sensing Using Long-Phosphorescence-Lifetime Cationic Ir(III) Complexes With Coumarin 6 and 545T...

Area of Science:

• Biochemistry and Biophysics
• Cell Biology
• Materials Science

Background:

• Intracellular oxygen (O₂) monitoring is vital for understanding cellular functions and diseases like cancer and ischemia.
• Hypoxic conditions significantly impact cell proliferation, differentiation, and metabolism.
• Existing methods for O₂ measurement may lack the sensitivity or real-time capabilities required for dynamic cellular studies.

Purpose of the Study:

• To develop novel small-molecule intracellular O₂ probes based on cationic iridium(III) complexes.
• To investigate the feasibility of using these probes for real-time O₂ monitoring in living cells.
• To evaluate the probes' performance using microplate readers and phosphorescence lifetime imaging microscopy (PLIM).

Main Methods:

• Synthesis of iridium(III) complexes C6-BA and C545T-BA.
• Characterization of photophysical properties, including absorption, emission, quantum yield, and lifetime.
• Cellular uptake studies and assessment of O₂ sensitivity in cultured cells using microplate reader and PLIM.

Main Results:

• C6-BA and C545T-BA complexes exhibit strong absorption, high quantum yields, and long emission lifetimes.
• The probes demonstrate efficient cellular uptake and high sensitivity to intracellular O₂ levels.
• Real-time tracking of cellular O₂ tension changes and heterogeneous O₂ distribution were achieved using microplate reader and PLIM.

Conclusions:

• C6-BA and C545T-BA are effective probes for real-time intracellular oxygen monitoring in living cells.
• The developed probes facilitate the study of cellular oxygen dynamics in physiological and pathological conditions.
• Microplate reader and PLIM technologies combined with these probes offer powerful tools for cellular O₂ tension analysis.