Time-resolved singlet-oxygen luminescence detection with an efficient and practical semiconductor single-photon...

Area of Science:

• Biomedical Optics
• Photochemistry
• Clinical Diagnostics

Background:

• Direct detection of singlet oxygen luminescence (1270 nm) is challenging for clinical photodynamic therapy due to low emission probability and detector limitations.
• Existing methods struggle with low geometric collection efficiency in clinical settings like fiber-based systems or microscopy.

Purpose of the Study:

• To propose and characterize a practical setup for direct singlet oxygen detection using a negative-feedback avalanche diode detector.
• To provide a viable alternative for singlet oxygen measurement in various clinical scenarios, particularly those with limited collection efficiency.
• To enable accurate quantum yield measurements of photosensitizers for site-selective photodynamic therapy.

Main Methods:

• Development of a novel detection setup utilizing a negative-feedback avalanche diode.
• Characterization of the setup using Rose Bengal as a standard photosensitizer.
• Application of the setup to measure singlet oxygen quantum yield for new photosensitizer candidates.

Main Results:

• The proposed negative-feedback avalanche diode detector setup demonstrates practical viability for singlet oxygen detection.
• The system is effective even in scenarios with limited geometric collection efficiency.
• Accurate singlet oxygen quantum yields were measured for novel photosensitizers.

Conclusions:

• The developed detector setup offers a practical and effective solution for direct singlet oxygen detection in photodynamic therapy.
• This technology has significant potential for improving photosensitizer development and clinical applications, especially in challenging geometries.
• The setup facilitates precise quantum yield measurements, aiding in the advancement of site-selective photodynamic therapy.