Depth-resolved fluorescence spectroscopy reveals layered structure of tissue.

A confocal fluorescence spectroscopy system is instrumented to study depth-resolved autofluorescence in biological tissue. The system provides the capability of optical sectioning with the maximal detectiondepth up to 120 m in the examined tissue samples. It was found that the topmost keratinizing epithelial layer produces strong fluorescence similar to collagen. The fluorescence signal from epithelial tissue between the keratinizing layer and stroma can be well resolved. The study results show that depth-resolved fluorescence spectroscopy has the potential to provide more accurate information for the diagnosis of tissue pathology.