Raman Spectroscopy for Biomedical Applications: From Label-free Cancer Cell Sorting to Imaging

This work presents the use of a Raman-based device and its integration/correlation with ultrasensitive microscopies (surface-enhanced Raman microscopy and confocal microscopy) for the molecular imaging and classification of normal lymphocytic B-cell and different leukemia cells from peripheral blood samples. The label-free Raman approach allowed for categorization of leukocytes into their respective lineage based on the biochemical information provided by Raman spectra. Furthermore, the single-point Raman analysis permitted the accurate discrimination of normal B-cells and leukemia-transformed cell lines (RS4;11, REH, MN60 cells), and more significantly, between leukemia cells in different differentiation/maturation stages. Raman imaging successfully and without cell destruction provided non-destructively information on the cell morphology, similarly to the standard May Grünwald-Giemsa histochemical staining protocol, but without the requirements for sample preparation. Finally, the specific analysis of the leukemic cell membrane by surface enhanced Raman scattering is shown. The reported results are promising for the development of a Raman-based protocol for the diagnosis and the complete morphofunctional assessment of cancer cells.