Post-staining Raman analysis of histological sections following decolorization.

Hematoxylin and eosin (HE) staining of tissue sections is a powerful tool for observing changes in the tissue structure and is used as the most fundamental and vital technique in histology. However, xenobiotics such as polymers and inorganic or organic materials have low dyeability, making it difficult to observe the distribution of materials across tissues. Raman spectroscopy is an advantageous technique for identifying materials in tissues using spectroscopic fingerprints by laser irradiation without staining. In this study, we developed a combined method for morphological observation and Raman spectral acquisition on the identical tissue slide by employing a decolorization step to remove eosin-induced fluorescence in HE-stained samples. Our method eliminated the fluorescence background and allowed the identical-field pathological observation, enabling simultaneous identification of biological responses and materials in tissues.