Figure 4.

FTIR imaging of MCF7, MDA-MB-231, SKBR3 and SUM149 fixed single cells. (A) Illustration of a white light image of MCF7 single fixed cell (left) and its corresponding FTIR image (right). Scale bar: 10 µm; (B) Normalized second derivative of mean spectrum (n = 10) of each cell type. Spectra are offset for clarity; (C) HCA analysis and (D) PCA score plot of MCF7 (full red circles), MDA-MB-231 (full blue squares), SKBR3 (full green triangles) and SUM149 (black crosses). Both analyses were performed on normalized mean second derivative spectra using frequency range 1350–900 cm⁻¹.