Singlet oxygen phosphorescence lifetime imaging based on a fluorescence lifetime imaging microscope.

Area of Science:

• Biophysics
• Photochemistry
• Microscopy

Background:

• Singlet oxygen phosphorescence (SOP) is an infrared emission from O2(a(1)Δg).
• Capturing weak SOP signals requires specialized microscopy techniques.

Purpose of the Study:

• To investigate the feasibility of singlet oxygen phosphorescence (SOP) lifetime imaging microscopy.
• To adapt a fluorescence lifetime imaging microscope (FLIM) for SOP detection.

Main Methods:

• A modified FLIM system was employed, incorporating a dichroic mirror to separate SOP signals from C60 photoluminescence (C60-PL).
• Simultaneous confocal C60-PL and nonconfocal SOP imaging were achieved using laser-scanning mode.

Main Results:

• The study identified infrared-incompatible scanners as an obstacle to confocal SOP imaging, suggesting infrared-compatible scanners as a solution.
• Alternative methods for confocal SOP imaging, including stage-scanning mode with a pinhole, were proposed.
• The exceptionally long imaging time for SOP was noted as a significant challenge, with point measurements proposed as a compromise.

Conclusions:

• The modified FLIM system demonstrates the feasibility of SOP lifetime imaging.
• Overcoming technical challenges, such as scanner compatibility and imaging time, is crucial for advancing SOP imaging applications.