Real-time tracing the changes in the intracellular pH value during apoptosis by near-infrared ratiometric fluorescence imaging

We developed a near-infrared ratiometric fluorescent nanoprobe with single-excitation dual-emission. The proposed nanoprobe was applied for real-time monitoring the changes in the pH value during hydrogen peroxide-induced apoptosis by ratio imaging. The pH value of HeLa cells changed from 6.6 to 5.6 after H₂O₂ (100 μM) stimulation for 40 min.