Autofluorescence spectroscopy of epithelial tissues

Area of Science:

• Biomedical Optics
• Tissue Spectroscopy
• Fluorescence Imaging

Background:

• Epithelial tissue autofluorescence is key for disease diagnosis.
• Keratinization in squamous epithelium can interfere with diagnostic signals.
• Understanding autofluorescence properties is crucial for accurate tissue analysis.

Purpose of the Study:

• To investigate the autofluorescence properties of keratinized and non-keratinized epithelial tissues.
• To assess the impact of keratinization on endogenous fluorescence signals.
• To evaluate depth-resolved fluorescence spectroscopy for epithelial tissue diagnosis.

Main Methods:

• Utilized a depth-resolved fluorescence spectroscopy system with multiple excitation wavelengths.
• Studied autofluorescence in rabbit and human epithelial tissues.
• Analyzed fluorescence signals from different tissue sublayers.

Main Results:

• Keratinization in squamous epithelium exhibits strong fluorescence, interfering with NADH/FAD and collagen signals.
• Keratinized layers attenuate excitation light, reducing signal from deeper tissues.
• Excitation at 355 nm resolved tissue layers; 405 nm estimated epithelial redox ratios.
• Columnar epithelium autofluorescence is dominated by NADH and FAD signals.

Conclusions:

• Depth-resolved measurements are essential to differentiate autofluorescence signals from epithelial tissue sublayers.
• Keratin fluorescence complicates precancer diagnosis by masking critical endogenous signals.
• Fluorescence spectroscopy offers a promising tool for accurate, non-invasive tissue diagnosis.