Fig. 5: Raman imaging of various liver tissue slices.

a Typical Raman spectrum of liver tissue slices in the range of 2000–3400 cm⁻¹ (purple line); the Raman spectra of pure protein (blue line) and lipids (yellow line) are also resolved by the SMCR algorithm. The Raman peak at 2930 cm⁻¹ (arrow 3) is related to protein, and peaks around 2855 cm⁻¹ (arrow 1), 2885 cm⁻¹ (arrow 2), and 3007 cm⁻¹ (arrow 4) are characteristic of lipids. b–d SMCR-reconstructed concentration maps of lipids (b) and protein (c) in normal liver tissue; d is an overlay of the two. To merge the two images, the minimum LUT value of yellow (lipids) was adjusted. e–i Bright-field images of the mapping test area and corresponding H&E-stained, SMCR-derived Raman, and corresponding 3D surface profile images of normal liver tissue (e). f–i show other tissue regions with typical morphologies, including cancerization (f), steatohepatitis (g), fibrosis (h), and connective (i) tissues. All scale bars are 10 µm.