Figure 3
Multivariate analysis of the Raman spectra. (A) Raman spectra of reference lipid molecules, PC1 and PC2 that were considered for CLS fitting. The grey lines highlight the correspondences between the peaks of the standard lipids and the PC loadings. (B) Scatter plot of the PCA results showing the PC1 and PC2 scores assigned to each spectrum recorded from the EVs of BM-MSCs (pink), ASCs (blue) and DFs (green). Each square represents one spectrum. The scatter plot shows that a positive PC1 score described ASC-derived EVs better than those derived from DFs and BM-MSCs, whereas a positive PC2 score better described EVs derived from BM-MSC. (C) CLS scores obtained after fitting the spectra of Cer (light green), Chol (green), SM (light blue), GM1 (blue), PCh (pink), PE (red) and PA (violet) with the PC1 and PC2 loadings. The positive and negative scores obtained after CLS fitting are visualized as a bar graph and respectively indicate the contribution of each standard molecules to the positive or negative peaks visible in the PC1 and PC2 loadings. Cer: ceramide; Chol: cholesterol; SM: sphingomyelin; GM1: monosialotetrahexosylganglioside; PCh: phosphatidylcholine; PE: phosphatidylethanolamine; PA: phosphatidic acid.
